Richtige Fernseher haben Röhren!

Richtige Fernseher haben Röhren!

In Brief: On this site you will find pictures and information about some of the electronic, electrical and electrotechnical technology relics that the Frank Sharp Private museum has accumulated over the years .

Premise: There are lots of vintage electrical and electronic items that have not survived well or even completely disappeared and forgotten.

Or are not being collected nowadays in proportion to their significance or prevalence in their heyday, this is bad and the main part of the death land. The heavy, ugly sarcophagus; models with few endearing qualities, devices that have some over-riding disadvantage to ownership such as heavy weight,toxicity or inflated value when dismantled, tend to be under-represented by all but the most comprehensive collections and museums. They get relegated to the bottom of the wants list, derided as 'more trouble than they are worth', or just forgotten entirely. As a result, I started to notice gaps in the current representation of the history of electronic and electrical technology to the interested member of the public.


Following this idea around a bit, convinced me that a collection of the peculiar alone could not hope to survive on its own merits, but a museum that gave equal display space to the popular and the unpopular, would bring things to the attention of the average person that he has previously passed by or been shielded from. It's a matter of culture. From this, the Obsolete Technology Tellye Web Museum concept developed and all my other things too. It's an open platform for all electrical Electronic TV technology to have its few, but NOT last, moments of fame in a working, hand-on environment. We'll never own Colossus or Faraday's first transformer, but I can show things that you can't see at the Science Museum, and let you play with things that the Smithsonian can't allow people to touch, because my remit is different.

There was a society once that was the polar opposite of our disposable, junk society. A whole nation was built on the idea of placing quality before quantity in all things. The goal was not “more and newer,” but “better and higher" .This attitude was reflected not only in the manufacturing of material goods, but also in the realms of art and architecture, as well as in the social fabric of everyday life. The goal was for each new cohort of children to stand on a higher level than the preceding cohort: they were to be healthier, stronger, more intelligent, and more vibrant in every way.

The society that prioritized human, social and material quality is a Winner. Truly, it is the high point of all Western civilization. Consequently, its defeat meant the defeat of civilization itself.

Today, the West is headed for the abyss. For the ultimate fate of our disposable society is for that society itself to be disposed of. And this will happen sooner, rather than later.

OLD, but ORIGINAL, Well made, Funny, Not remotely controlled............. and not Made in CHINA.

How to use the site:

- If you landed here via any Search Engine, you will get what you searched for and you can search more using the search this blog feature provided by Google. You can visit more posts scrolling the left blog archive of all posts of the month/year,
or you can click on the main photo-page to start from the main page. Doing so it starts from the most recent post to the older post simple clicking on the Older Post button on the bottom of each page after reading , post after post.

You can even visit all posts, time to time, when reaching the bottom end of each page and click on the Older Post button.

- If you arrived here at the main page via bookmark you can visit all the site scrolling the left blog archive of all posts of the month/year pointing were you want , or more simple You can even visit all blog posts, from newer to older, clicking at the end of each bottom page on the Older Post button.
So you can see all the blog/site content surfing all pages in it.

- The search this blog feature provided by Google is a real search engine. If you're pointing particular things it will search IT for you; or you can place a brand name in the search query at your choice and visit all results page by page. It's useful since the content of the site is very large.

Note that if you don't find what you searched for, try it after a period of time; the site is a never ending job !

Every CRT Television saved let revive knowledge, thoughts, moments of the past life which will never return again.........

Many contemporary "televisions" (more correctly named as displays) would not have this level of staying power, many would ware out or require major services within just five years or less and of course, there is that perennial bug bear of planned obsolescence where components are deliberately designed to fail and, or manufactured with limited edition specificities..... and without considering........picture......sound........quality........

..............The bitterness of poor quality is remembered long after the sweetness of todays funny gadgets low price has faded from memory........ . . . . . .....
Don't forget the past, the end of the world is upon us! Pretty soon it will all turn to dust!

Have big FUN ! !
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©2010, 2011, 2012, 2013, 2014 Frank Sharp - You do not have permission to copy photos and words from this blog, and any content may be never used it for auctions or commercial purposes, however feel free to post anything you see here with a courtesy link back, btw a link to the original post here , is mandatory.
All sets and apparates appearing here are property of
Engineer Frank Sharp. NOTHING HERE IS FOR SALE !

Friday, May 11, 2012

PHILIPS 23TX401A SUPER-ONTVANGER CHASSIS INTERNAL VIEW.

















PHILIPS 23TX401A SUPER-ONTVANGER REMOTE CONTROLLED TELEVISION TUNER MOTOR SWITCHING CIRCUIT:
1. In a television tuner, the combination of, a channel selector shaft rotatable to a plurality of channel selecting positions, a support structure rotatable with said selector shaft and carrying a plurality of individually adjustable gear elements for fine tuning adjustment to different television channels, a fine tuning shaft concentric with said selector shaft, said adjustable gear elements moving in a predetermined path around said selector shaft as said support structure is rotated, a fine tuning gear secured to said fine tuning shaft, a movable member, an auxiliary shaft journalled for rotation in said movable member and bodily movable therewith, first gear means on said auxiliary shaft and positioned outside said predetermined path of said adjustable gear elements, means for interconnecting said auxiliary shaft and said fine tuning gear, an actuating plate rotatably mounted on said fine tuning shaft, slip clutch means interconnecting said actuating plate and said fine tuning shaft, and means responsive to rotation of said actuating plate upon initial rotation of said fine tuning shaft in either direction for moving said movable member so that said first gear means is moved inwardly into engagement with a selected one of said adjustable gear elements and said interconnecting means is moved into engagement with said fine tuning gear, said slip clutch means acting upon the application of additional torque to said fine tuning shaft in the same direction to disengage said actuating plate from said fine tuning shaft thereby to permit adjustment of said selected gear element while maintaining said first gear means in engagement therewith upon further rotation of said fine tuning shaft in said same direction.
1. In a television tuner, the combination of, a channel selector shaft rotatable to a plurality of channel selecting positions, a support structure rotatable with said selector shaft and carrying a plurality of individually adjustable gear elements for fine adjustment to different television channels, a fine tuning shaft concentric with said selector shaft, said adjustable gear elements moving in a predetermined path around said selector shaft as said support structure is rotated, a fine tuning gear secured to said fine tuning shaft, a movable member, an auxiliary shaft journalled for rotation in said movable member and and bodily movable therewith, first gear means on said auxiliary shaft and positioned outside said predetermined path of said adjustable gear elements, means for interconnecting said auxiliary shaft and said fine tuning gear, an actuating plate rotatably mounted on said fine tuning shaft, slip clutch means interconnecting said actuating plate and said fine tuning shaft, and means reponsive to rotation of said actuating plate upon initial rotation of said fine tuning shaft in either direction for moving said movable member so that said first gear means is moved inwardly into engagement with a selected one of said adjustable gear elements and said interconnecting means is moved into engagement with said fine tuning gear, said slip clutch means acting upon the application of additional torque to said fine tuning shaft in the same direction to disengage said actuating plate from said fine tuning shaft thereby to permit adjustment of said selected gear element while maintaining said first gear means in engagement therewith upon further rotation of said fine tuning shaft in said same direction. 2. In a television tuner, the combination of, a channel selector shaft rotatable to a plurality of channel selecting positions, a support structure rotatable with said selector shaft and carrying a plurality of individually adjustable gear elements for fine tuning adjustment to different television channels, a fine tuning shaft concentric with said selector shaft, said adjustable gear elements moving in a predetermined path around said selector shaft as said support structure is rotated, a fine tuning gear secured to said fine tuning shaft, a movable member, an auxiliary shaft journalled for rotation in said movable member and bodily movable therewith, first gear means on said auxiliary shaft and positioned outside said predetermined path of said adjustable gear elements, means driven from said auxiliary shaft and engageable with said fine tuning gear, an actuating plate rotatably mounted on said fine tuning shaft, slip clutch means interconnecting said actuating plate and said fine tuning shaft, a pair of spaced apart projections on said actuating plate, and means responsive to movement of said projections upon initial rotation of said fine tuning shaft in either direction for moving said movable member so that said first gear means is moved inwardly into engagement with a selected one of said adjustable gear elements and said drive means is moved into engagement with said fine tuning gear, said slip clutch means acting upon the application of additional torque to said fine tuning shaft in the same direction to disengage said actuating plate from said fine tuning shaft thereby to permit adjustment of said selected gear element while maintaining said first gear means in engagement therewith upon further rotation of said fine tuning shaft in said same direction. 3. In a television tuner, the combination of, a channel selector shaft rotatable to a plurality of channel selecting positions, a support structure rotatable with said selector shaft and carrying a plurality of individually adjustable gear elements for fine tuning adjustment to different television channels, a fine tuning shaft concentric with said selector shaft, said adjustable gear elements moving in a predetermined path around said selector shaft as said support structure is rotated, a fine tuning gear secured to said fine tuning shaft, a movable member, an auxiliary shaft journalled for rotation in said movable member and bodily movable therewith, first gear means on said auxiliary shaft and positioned outside said predetermined path of said adjustable gear elements, second gear means driven from said auxiliary shaft and engageable with said fine tuning gear, an actuating plate rotatably mounted on said fine tuning shaft, slip clutch means between said actuating plate and said fine tuning shaft, a pair of lugs on said actuating plate and positioned on opposite sides of said fine tuning shaft, and means responsive to movement of either of said lugs upon initial rotation of said fine tuning shaft in either direction for moving said
movable member so that said first gear means is moved inwardly into engagement with a selected one of said adjustable gear elements and said second gear means is moved into engagement with said fine tuning gear, said slip clutch means acting upon the application of additional torque to said fine tuning shaft in the same direction to disengage said actuating plate from said fine tuning shaft, thereby to permit adjustment of said selected gear element upon further rotation of said fine tuning shaft in the same direction while maintaining said first gear means in engagement therewith. 4. In a television tuner, the combination of, a channel selector shaft rotatable to a plurality of channel selecting positions, a support structure rotatable with said selector shaft and carrying a plurality of individual adjustable gear elements for fine tuning adjustment to different television channels, a fine tuning shaft concentric with said selector shaft, said adjustable gear elements moving in a predetermined path around said selector shaft as said support structure is rotated, a fine tuning gear secured to said fine tuning shaft, a movable member, an auxiliary shaft journalled for rotation in said movable member and bodily movable therewith, first gear means on said auxiliary shaft and positioned outside said predetermined path of said adjustable gear elements, second gear means driven from said auxiliary shaft and engageable with said fine tuning gear, an actuating plate rotatably mounted on said fine tuning shaft, slip clutch means between said actuating plate and said fine tuning shaft, a pair of lugs on said actuating plate and positioned on opposite sides of said fine tuning shaft, and means responsive to movement of either of said lugs upon initial rotation of said fine tuning shaft in either direction for moving said movable member so that said auxiliary shaft is moved toward said selector shaft while remaining parallel thereto, said first gear means being moved inwardly into engagement with a selected one of said adjustable gear elements and said second gear means being moved into engagement with said fine tuning gear upon said inward movement of said member, said slip clutch means acting upon the application of additional torque to said fine tuning shaft in the same direction to disengage said actuating plate from said fine tuning shaft, thereby to permit adjustment of said selected gear element upon further rotation of said fine tuning shaft in the same direction while maintaining said first gear means in engagement therewith. 5. In a television tuner, the combination of, a channel selector shaft rotatable to a plurality of channel selecting positions, a support structure rotatable with said selector shaft and carrying a plurality of individually adjustable gear elements for fine tuning adjustment to different television channels, a fine tuning shaft concentric with said selector shaft, said adjustable gear elements moving in a predetermined path around said selector shaft as said support structure is rotated, a fine tuning gear secured to said fine tuning shaft, a movable member, an auxiliary shaft journalled for rotation in said movable member and bodily movable therewith, a first gear on said auxiliary shaft and positioned outside said predetermined path of said adjustable gear elements, a second gear on said auxiliary shaft and engageable with said fine tuning gear, an actuating plate rotatably mounted on said fine tuning shaft, slip clutch means
between said actuating plate and said fine tuning gear, a pair of lugs on the periphery of said actuating plate and positioned on opposite sides of said fine tuning shaft, and means responsive to movement of either of said lugs upon initial rotation of said fine tuning shaft in either direction for moving said movable member so that said first gear is moved inwardly into engagement with a selected one of said adjustable gear elements and said second gear is moved into engagement with said fine tuning gear, said slip clutch means acting upon the application of additional torque to said fine tuning shaft in the same direction to disengage said actuating plate from said fine tuning gear, thereby to permit adjustment of said selected gear element upon further rotation of said fine tuning shaft in the same direction while maintaining said first gear in engagement therewith. 6. In a television tuner, the combination of, a channel selector shaft rotatable to a plurality of channel selecting positions, a support structure rotatable with said selector shaft and carrying a plurality of individually adjustable gear elements for fine tuning adjustment to different television channels, a fine tuning shaft concentric with said selector shaft, said adjustable gear elements moving in a predetermined path around said selector shaft as said support structure is rotated, a fine tuning gear secured to said fine tuning shaft, a movable member, an auxiliary shaft positioned parallel to but offset from said selector shaft and journalled for rotation in said movable member and bodily movable therewith, a first gear on said auxiliary shaft and positioned outside said predetermined path of said adjustable gear elements, a second gear on said auxiliary shaft and engageable with said fine tuning gear, an actuating plate rotatably mounted on said fine tuning shaft, slip clutch means between said actuating plate and said fine tuning gear, a pair of lugs on the periphery of said actuating plate and positioned on opposite sides of said fine tuning shaft, and means responsive to movement of either of said lugs upon initial rotation of said fine tuning shaft in either direction of moving said movable member so that said auxiliary shaft is moved toward said selector shaft while remaining parallel thereto, said first gear is moved inwardly into engagement with a selected one of said adjustable gear elements and said second gear is moved into engagement with said fine tuning gear said slip clutch means acting upon the application of additional torque to said fine tuning shaft in the same direction to disengage said actuating plate from said fine tuning gear, thereby to permit adjustment of said selected gear element upon further rotation of said fine tuning shaft in the same direction while maintaining said first gear in engagement therewith. 7. In a television tuner, the combination of, a channel selector shaft rotatable to a plurality of channel selecting positions, a support structure rotatable with said selector shaft and carrying a plurality of individually adjustable gear elements for fine tuning adjustment to different television channels, a fine tuning shaft concentric with said selector shaft, said adjustable gear elements moving in a predetermined path around said selector shaft as said support structure is rotated, a fine tuning gear secured to said fine tuning shaft, a movable member, an auxiliary shaft positioned parallel to but offset from said selector shaft and journalled for rotation in said movable member and bodily movable therewith, a first gear on said auxiliary shaft and positioned outside said predetermined path of said adjustable gear elements, a second gear on said auxiliary shaft and normally positioned so that only the tips of the teeth thereof engage the tips of the teeth of said fine tuning gear, an actuating plate rotatably mounted on said fine tuning shaft, slip clutch means between said actuating plate and said fine tuning gear, a pair of lugs on the periphery of said actuating plate and positioned on opposite sides of said fine tuning shaft, and means responsive to movement of either of said lugs upon initial rotation of said fine tuning shaft in either direction for moving said movable member so that said auxiliary shaft is moved toward said selector shaft while remaining parallel thereto, said first gear is moved inwardly into engagement with a selected one of said adjustable gear elements and said second gear is moved into substantially full engagement with said fine tuning gear, said slip clutch means acting upon the application of additional torque to said fine tuning shaft in the same direction to disengage said actuating plate from said fine tuning gear, thereby to permit adjustment of said selected gear element upon further rotation of said fine tuning shaft in the same direction while maintaining said first gear in engagement therewith. 8. In a television tuner, the combination of, a channel selector shaft rotatable to a plurality of channel selecting positions, a support structure rotatable with said selector shaft and carrying a plurality of individually adjustable gear elements for fine tuning adjustment to different television channels, a fine tuning member concentric with said selector shaft, said adjustable gear elements moving in a predetermined path around said selector shaft as said support structure is rotated, a fine tuning gear secured to said fine tuning member, a movable member, an auxiliary shaft journalled for rotation in said movable member and bodily movable therewith, first gear means on said auxiliary shaft and positioned outside said predetermined path of said adjustable gear elements, means for interconnecting said auxiliary shaft and said fine tuning gear, an actuating member, slip clutch means interconnecting said actuating member and said fine tuning member so that said actuating member is movable with said fine tuning member, and means responsive to rotation of said actuating member upon initial rotation of said fine tuning member in either direction for moving said movable member so that said first gear means is moved inwardly into engagement with a selected one of said adjustable gear elements, while said auxiliary shaft remains parallel to said selector shaft, said slip clutch means acting upon the application of additional torque to said fine tuning member in the same direction to cause said fine tuning member to slip with respect to said actuating member, thereby the permit adjustment of said selected gear element through said interconnecting means upon further rotation of said fine tuning member in said same direction while maintaining said first gear means in engagement with said selected gear element. 9. In a television tuner, the combination of, a channel selector shaft rotatable to a plurality of channel selecting positions, a support structure rotatable with said selector shaft and carrying a plurality of individually adjustable gear elements for fine tuning adjustment to different television channels, a fine tuning member concentric with said selector shaft, said adjustable gear elements moving in a predetermined path around said selector shaft as said support structure is rotated, a fine tuning gear secured to said fine tuning member, a movable member, an auxiliary shaft journalled for rotation in said movable member and bodily movable therewith, first gear means on said auxiliary shaft and positioned outside said predetermined path of said adjustable gear elements, means for interconnecting said auxiliary shaft and said fine tuning gear, an actuating member having a pair of spaced apart drive means, slip clutch means interconnecting said actuating member and said fine tuning member so that said actuating member is movable with said fine tuning member, and means responsive to movement of either of said drive means when said actuating member is rotated upon initial rotation of said fine tuning member in either direction for moving said movable member so that said first gear means is moved inwardly into engagement with a selected one of said adjustable gear elements while said auxiliary shaft remains parallel to said selector shaft, said slip clutch means acting upon the application of additional torque to said fine tuning member in the same direction to cause said fine tuning member to slip with respect to said actuating member, thereby to permit adjustment of said selected gear element through said interconnecting means upon further rotation of said fine tuning member in said same direction while maintaining said first gear means in engagement with said selected gear element.

10. A television tuner comprising a channel selector switch; an operating shaft therefore; a tuning circuit for each channel and including an individual tuning slug and a position adjusting gear therefore; a tuning assembly including a pivoted supporting plate carrying a driven gear coaxially mounted on a shaft to drive an adjusting drive pinion to engage and operate the position adjusting gear for the tuning slug of a tuning circuit selected by the channel selector switch; bias means normally biasing the pivoted supporting plate and tuning assembly to nonoperating position with the adjusting drive pinion out of engagement with the position adjusting slug gear of the selected channel; a fine-tune shaft; and means on, and controlled by, rotation of said fine-tune shaft for first laterally shifting the pivoted supporting plate and the tuning assembly to mesh the drive pinion with the slug gear, and for then tuning said driven gear on said supporting plate to turn the drive pinion and rotate the slug gear. 11. In a tuning assembly comprising a body, a plurality of individual adjustable tuning elements on said body, a support, means for movably mounting said body on said support for bringing said tuning elements sequentially to a given station, and adjusting means adjacent a given station on said support for engaging a tuning element at said station and adjusting it; the improvement which comprises said adjusting means comprising first means normally disengaged from the tuning element at said station but movable into engagement therewith, and thereafter further movable to adjust said tuning element, second means operatively connected to said first means for moving it into engagement with the tuning element, and third means normally disengaged from said first means and effective, when engaged therewith, to further move said first means to adjust said tuning element, said first means being movable into engagement with said third means substantially at the same time said first means moves into engagement with said tuning element, and a manual control means operatively connected to said second and third means and effective to actuate both of them upon manual movement of said control means in only a single sense.
Description:
The present invention relates to television tuners, and more particularly, to television tuners of the type with employ a station selector shaft having a plurality of channel selecting positions, one position being provided for each television channel to be received.

Present-day television tuners of the rotary type include an incrementally rotatable channel selector shaft for selectively connecting certain ones of a plurality of tuned circuit elements into operative circuit relationship with other tuner elements for each of a plurality of channel selecting positions. Because of a difficulty of accurately setting the values of the tuned circuit elements, and because of the desirability of accurately tuning the local oscillator for clear reception in each of the channel positions of the station selector shaft, it is customary to include in the oscillator circuit an impedance device having an adjustable value. This impedance device, which may be either an inductance or a capacitor, is conventionally adjusted by means of a vernier or fine tuning shaft, frequently concentrically mounted with respect to the channel selector shaft, which is connected to the adjustable impedance and is adjustable by the viewer for each different channel.

Various memory fine tuning arrangements have been proposed to eliminate the necessity for adjustment of the vernier tuning shaft of the tuner by the user in each channel position of the station selector shaft. One such arrangement employs a single vernier tuning impedance which is operatively connected in the oscillator circuit at all times and is automatically adjusted by a memory tuning mechanism in each channel selecting position of the selector shaft so as to provide a desired setting of the vernier tuning impedance, which setting may, however, be changed manually by the user if desired. Such an arrangement is described and claimed in U.S. Patent No. 2,947,866 issued August 2, 1960, to Alarico A. Valdettaro and Stanley R. Meadows, and assigned to the same assignee as the present application. In accordance with the present invention the manual adjustment of vernier tuning by the user is accomplished by manipulation of the fine tuning knob in the conventional manner while at the same time providing a memory tuning function so that the user is aware that memory fine tuning is provided only by the fact that he does not have to adjust the fine tuning knob very frequently.

It is becoming increasingly popular with television receiving sets to provide motor driven means for controlling the positioning of the station selector shaft, generally from a remote control location. In such instances, it is particularly desirable that a memory fine tuning function is provided so that fine tuning will be automatically accomplished during the selection of the desired channel and at the same time it is desirable to provide means for the users of the television receivers manually to adjust the fine tuning device. Additionally, it is desirable that the remote controlled motor driven television tuner stop at selectable channel positions and that the particular channel positions at which the television tuner stops are readily selectable by the operator of the set at will. Furthermore, it is desirable to provide facilities for selecting active channel positions without providing additional knobs or controls on the front panel of the receiver.

It is, therefore, an object of the present invention to provide a new and improved television tuner wherein an improved memory fine tuning arrangement is provided for automatically adjusting the fine tuning of the tuner in each channel selecting position of the station selector shaft.

It is a further object of the present invention to provide a new and improved television tuner wherein the fine tuning in each of the channel selecting positions is automatically accomplished while, at the same time, providing an arrangement whereby the user can manually readjust the fine tuning in any channel by manipulation of the fine tuning knob in the conventional manner.

It is another object of the present invention to provide a new and improved television tuner wherein motor driven facilities are provided for automatically rotating the channel selector shaft to preselected active channel positions while, at the same time, providing automatic adjustment of the fine tuning in each of these active channel positions.

It is a still further object of the present invention to provide a new and improved television tuner wherein motor driven facilities are provided for rotating the channel selector shaft of the tuner to desired channel selecting positions and wherein designation of particular channel positions as active channels can be accomplished by the user by manipulation of the conventional fine tuning knob of the tuner.

It is another object of the present invention to provide a new and improved television tuner which includes a single fine tuning impedance together with facilities for automatically adjusting the value of this impedance in each channel selecting position of the main tuning shaft of the tuner.

It is still another object of the present invention to provide a new and improved television tuner wherein a new and improved memory fine tuning mechanism is provided which cooperates with motor driven facilities for permitting the user to select which of the available channels will be selectable as active channels.

It is a further object of the present invention to provide a new and improved television tuner having fine tuning means which is settable to control the remote operation of the tuner.

Briefly, in accordance with the present invention, a memory fine tuning mechanism is provided by employing a number of individually adjustable elements which are rotatable with the channel selector shaft of the tuner. In one embodiment these individual elements may all act successively to position a common vernier tuning impedance while in another embodiment of the invention these elements may be individually associated with the different oscillator coils which are employed in tuning the tuner to different television channels. With either embodiment, the fine tuning knob of the tuner, which is concentric with the station selector knob of the tuner, is releasably engageable with a selected one of these adjustable elements by means of a slip clutch arrangement which is effective to engage the fine tuning knob with the selected adjustable element upon rotation of the fine tuning knob in either direction. Upon further rotation of the knob after it has become engaged with the adjustable element the adjustable element is adjusted in position so that the desired fine tuning may be effected in any channel position of the tuner. However, upon release of the fine tuning knob this knob is disconnected from the adjustable element and remains disconnected therefrom until a fine tuning adjustment on another adjustable element is required.

In accordance with a further feature of the invention, motor driven facilities are provided for automatically rotating the channel selector shaft of the tuner in response to an initiating impulse which may be remotely produced. The motor driven facilities will rotate the shaft until the next active channel is encountered. In order to permit the user to preselect any of the 12 available channels as active channels within his receiving area, facilities are provided for designation of a channel as an active or inactive channel by manipulation of the fine tuning knob of the tuner. More particularly, when the user wishes to designate a channel as an inactive channel, he rotates the station selector shaft to this particular channel and then rotates the fine tuning knob in a particular direction until a stop is encountered. When this occurs the motor driven facilities are set up so that they will not stop the channel selector shaft on this particular channel selecting position. In this manner the tuner can be set up so that it can be stopped only on a few desired channel positions which are active in the particular receiving area and thereafter the motor driven facilities will function to stop the tuner only at these selected channel positions. However, these positions can be changed at will by merely manipulating the fine tuning control knob of the tuner in the manner described above.

The nature of the invention will best be understood when described in connection with accompanying drawings, in which:

FIG. 1 is a side elevational view of an improved television tuner according to the present invention;

FIG. 2 is a sectional front view of the television tuner of FIG. 1 taken along line 2--2 of FIG. 1 and illustrating fine tuning arrangement in disengaged position;

FIG. 3 is a sectional front view of the improved television tuner similar to that of FIG. 2 but illustrating the fine tuning arrangement in an engaged position;

FIG. 4 is a sectional front view taken along line 4--4 of FIG. 1 and further illustrating the fine tuning arrangement in a disengaged position;

FIG. 5 is a sectional front view of the improved television tuner similar to that of FIG. 4 but illustrating the fine tuning arrangement in an engaged position;

FIG. 6 is a top sectional view of the tuner of FIG. 1 taken along line 6--6 of FIG. 2 and illustrating the clutch arrangement in the fine tuning arrangement;

FIG. 7 is a partial sectional bottom view taken along line 7--7 of FIG. 1 and illustrating some of the adjustable members in one operating position;

FIG. 8 is a partial sectional bottom view similar to FIG. 7 but illustrating one of the adjustable members in yet another of its operative positions;

FIG. 9 is a partial sectional bottom view illustrating one of the adjustable members in yet another of its operative positions;

FIG. 10 is a partial side sectional elevational view illustrating the motor means for driving the selector shaft;

FIG. 11 is a partial sectional back view of the motor means taken along the 11--11 of FIG. 10;

FIG. 12 is a partial plan view, partly in section, illustrating one of the motor control switches;

FIG. 13 is a schematic view of the remote control electrical system;

FIG. 14 is a side view of another embodiment of a fine tuning arrangement according to the present invention with certain parts removed for clarity; and

FIG. 15 is a sectional front view taken along line 15--15 of FIG. 14, and illustrated with certain parts thereof shown in phantom for clarity.

Referring now to the drawings, and particularly to the embodiment of FIGS. 1 to 13, there is illustrated in FIG. 1 thereof the improved television tuner 20 and comprising an oscillator portion 22, a motor drive portion 24, and a memory tuning portion and channel selector 26. The television tuner 20 includes a substantially U-shaped chassis 28 having a front and a rear wall 30 and 32, respectively, and a top deck portion 34 on which are mounted the tube sockets for a pair of tubes 36 and 38. The oscillator portion 22 contains a rotary channel selector means (not shown), the forward end of which is supported by the front wall 30 and the rear end of which is supported by the rear wall 32. The channel selector means is controlled by a main tuning or channel selector shaft 52. In accordance with conventional practice, different ones of a plurality of tuned circuit elements are operatively connected in the television receiving circuit for each angular channel selecting position of the selector shaft 52. Moreover, a suitable detent assembly 54 is effectively interconnected between the selector shaft 52 and the chassis 28 to facilitate the accurate angular positioning the selector shaft 52 in each of its channel selecting positions. Accordingly, as the shaft 52 is rotated to successive channel selecting positions, a plurality of tuning elements are respectively connected in circuit with the antenna, mixer, and oscillator sections of the tuner for each of the channel selecting positions of the selector shaft 52. As the main tuning shaft 52 is rotated to retune the receiver, different ones of these tuned circuit elements are connected into circuit relationship with the oscillator circuit, thereby to selectively control the frequency of oscillation thereof.

In order to permit fine adjustment of the frequency of oscillation of the oscillator for each channel selecting position of the selector shaft 52, a variable tuning impedance, shown generally at 56, is connected in the oscillator circuit to enable adjustment of the frequency of oscillation of the oscillator throughout a relatively narrow range as compared to the range of frequencies controlled by the tuned circuit elements of the channel selector means as the selector shaft 52 is rotated through 360 degrees. As shown, the variable impedance 56 comprises a tubular support member 58 formed of an insulating material such, for example, as glass or ceramic, on which a pair of conductive elements are disposed in spaced apart relation. A conductive slug 60, which is preferably cylindrical in cross section, is slidably mounted in the bore of the support member 58 so that axial movement of the slug 60 within the member 58 adjusts the value of reactance in the circuit. The manner in which the impedance 56 is connected in circuit relation with the oscillator is known in the art and is more fully described, for example, in the aforementioned patent of Valdettaro and Meadows and need not be herein described.

In order to provide for varying the reactance of the impedance 56, the conductive slug 60 is secured to an insulated rod or movable element 62 which extends through an aperture in the front wall 30 of the chassis 28. A compression spring 64 biases the rod 62 outwardly so that the conductive slug 60 is urged into the tubular support member 58. Axial movement of the insulated rod 62 and the conductive slug 60 secured thereto is effective to vary the reactance of the impedance 56 and to fine-tune the oscillator circuit of the television receiving set.

In order to selectively adjust the variable tuning impedance 56 and to provide for operator selection of the desired channels, at each of the selected positions of the selector shaft 52, there is provided the memory tuning portion 26 secured to the front wall 30 of the chassis 28, and best illustrated in FIG. 1. The memory tuning portion 26 includes a cam assembly 70 including a first or back cam support plate 72 containing a plurality of bosses 74 each provided with an aperture and each of which represents a channel selecting position of the selector shaft 52. The cam support plate 72 contains a central boss 76 provided with a central bore through which the selector shaft 52 passes. The cam support plate 72 is keyed or otherwise secured to the selector shaft 52 so as to rotate with the selector shaft 52. The selector shaft 52 is further provided with a channel selector knob 78 keyed or otherwise secured to the selector shaft 52 to provide for manual rotation of the selector shaft 52 and simultaneous rotation of the cam support plate 72.

In order to provide for independent adjustment of the variable tuning impedance 56 at each of the channel selecting positions of the selector shaft 52, there is provided a plurality of independently adjustable cam members 80, each of which is positioned in an aperture in each of the bosses 74. Each of the cam members 80 is provided with a threaded portion 82 at its inner end and a hairpin type springn 84 is provided for each of the cam members 80 and positioned with one inner leg thereof biased into the root of the thread in the threaded portion 82, and secured in position by the engagement of the other leg thereof with its respective boss 74 on the opposite side of the cam support plate 72. In this manner, the cooperation between the hairpin spring 84 and the threads in the threaded portions 82 of the cam member 80 is effective to provide for threading the cam members into or out of the apertures in the support plate 72 upon rotation of the cam members 80.

In order to adjustably position the movable element 62 of the variable impedance 56 with respect to the selected one of the cam members 80, there is provided a cam follower element 86 (FIG. 7) having one end 86a thereof pivotally positioned in an aperture 88 in a side wall portion 90 secured to the chassis 28 and having the other end thereof engaging the movable element 62 of the variable impedance 56. The cam follower element 86 is biased outwardly from the variable impedance 56 by the compression spring 64. The cam follower element 86 is further provided with an L-shaped arm 86b which passes through an aperture 92 in the front wall 30 and is effective to engage the inner surface of the front wall 30 to limit the outward movement of the cam follower element 86. Moreover, the cam follower element 86 is provided with a convex cam portion 94 intermediate its ends. The cam assembly 70 is positioned on the selector shaft 52 relative to the cam follower element 86 and spaced therefrom such a distance so that the cam members 80 are selectively brought into engagement with the cam portion 94 of the cam follower element 86 at each of the channel selecting positions of the selector shaft 52 to provide the proper impedance of the variable impedance 56 at the particular selected channel. It will be understood that if the cam members 80 are screwed inwardly beyond their threaded limits, the hairpin spring 84 will rise out of the root of the threads in the threaded portion 82 of the cam members 80 and will ride over the crests to permit slippage of the cam member 80 without damage.

In order to adjust the individual independently adjustable member 80 associated with a particular selected channel, there is provided a gear train, represented generally at 96, and the clutch and gear assembly, hereinafter referred to as clutch assembly, and generally represented at 98, as best illustrated in FIGS. 2 to 5. The gear train 96 includes a driven gear 100 and a driving gear 102, each splined or otherwise secured to a rotatable shaft 104. The shaft 104 is rotatably mounted near the outer end of the legs of a generally U-shaped bracket 106; the legs of the bracket 106 near the inner end toward the bight portion thereof are pivotally mounted on a shaft 108 which may be supported by the side wall portion 90 from the chassis 28. In its disengaged or inoperative position illustrated in FIG. 4, the gear train 96 is biased with the driving gear 102 thereof out of engagement with the cam member 80 by a helical spring 110. The clutch assembly 98 is operative to pivot the gear train 96 into an engaged or operative position illustrated in FIGS. 3 and 5 about the shaft 108 toward the cam members 80 so that the driving gear 102 thereof engages a pinion gear or gear member 112 integrally formed with the cam members 80. Since the cam members 80 are adapted to thread axially in the cam assembly 70, and therefore axially with reference to the driving gear 102, the face 102a (FIG. 1) of the driving gear 102 has sufficient width to engage the pinion gear 112 throughout its axial movement.

The clutch assembly 98 is secured to one end of a fine tuning shaft 114 mounted for free rotation concentrically about the selector shaft 52. The outer end of the fine tuning shaft 114 is provided with a fine tuning knob 116 keyed or otherwise secured to the fine tuning shaft 114 to provide the manual rotation of the shaft 114. A tuning gear 118 is positioned on the fine tuning shaft 114 for rotation therewith and, in the illustrated embodiment, may be drivingly connected therewith through a dish-shaped spring 119, FIG. 6. The outer face of the tuning gear 118 contains a clutch facing 120 bonded or otherwise secured to the tuning gear 118. A fine tuning actuating plate 122 is rotatably mounted on the fine tuning shaft 114 and held against axial movement by a retainer 124. The dish-shaped spring 119 is effective to apply axial pressure between the actuating plate 122 and the tuning gear 118 through the clutch facing 120 so that manual rotation of the tuning gear 118 through the fine tuning shaft 114 is effective to provide a turning torque to the actuating plate 122 through the clutch facing 120; however, the axial load exerted by the spring 119 is light enough that slippage can occur between the actuating plate 122 and the tuning gear 118 when the restraining torque of the actuating plate 122 reaches a predetermined amount.

In order to move the gear train 96 into its engaged or operative position, so that the tuning gear 118 is in engagement with the driven gear 100 of the gear train 96, and so that the driving gear 102 of the gear train 96 is in engagement with the selected pinion gear 112, there is provided the generally V-shaped actuating spring 126 which interconnects the gear trains 96 and the clutch assembly 98. Specifically, the actuating spring 126 has a center portion 128 (FIGS. 2 and 3) positioned over the shaft 104 formed by an interconnecting pair of legs 130 each provided with a hook portion 132 and 134 at their lower ends. Moreover, the actuating plate 122 is provided with a pair of hook portions 136 and 138 near opposite sides thereof so that the hook portions 136 and 138 in the actuating plate 122 are effective to engage a respective one of the hook portions 132 and 134 upon rotation of the actuating plate 122. Initial rotation of the actuating plate 122 is effective to engage one of the hook portions 132 or 134 of the actuating spring 126 to pivot the gear train 96 about the shaft 108, for example, from the disengaged or inoperative position illustrated in FIG. 2 to the engaged or operative position illustrated in FIG. 3. While the torque transmitted through the clutch facing 120 from the tuning gear 118 to the actuating plate 122 is sufficient to hold the gear train 96 in this operative position, the clutch facing 120 is effective to permit rotation of the tuning gear 118 relative to the actuating plate 122 upon further rotation of the fine tuning shaft 114.

From the above description of the memory tuning portion 26, the operation of the improved memory fine tuning means is believed clear. However, briefly, the oscillator circuit of the television tuner 20 is fine-tuned through the axial movement of the movable element 62 into or out of the support member 58 of the variable tuning impedance 56. The exact positioning of the movable element 62 is controlled through the pivotally mounted cam follower element 86 which is provided with a cam portion 94. The cam assembly 70 contains a plurality of axially positionable independently adjustable cam members 80 adjustable by engagement of the threads thereof with the hairpin type spring 84. One such cam member 80 is provided for each of the channel selecting positions of the selector shaft 52. In order to rotate the selected one of the cam members 80 in the cam assembly 70, the fine tuning knob 116 may be manually rotated in the desired direction. Assuming that the fine tuning knob 116 is rotated clockwise, as viewed in FIGS. 2 to 5, the clutch assembly 98 is initially rotated clockwise about the fine tuning shaft 115 so that the hook portion 138 of the actuating plate 122 engages the hook portion 134 of the actuating spring 126, drawing the actuating spring 126 downwardly and pivoting the gear train 96 about the shaft 108 so that the driven gear 100 of the gear train 96 engages the tuning gear 118. Simultaneously, the driving gear 102 of the gear train 96 will engage the pinion gear 112 on the particular one of the cam members 80 which represent the selected channel for the particular channel selecting position of the selector shaft 52. Continued rotation of the tuning gear 118 through manual operation of the fine tuning knob 116 will cause slippage between the friction clutch facing 120 and the actuating plate 122 so that the tuning gear 118 is rotated beyond the initial position without further movement of the actuating plate 122. The friction afforded between the clutch facing 120 and the actuating plate 122 is light enough to provide for slippage during the manual adjusting operation; but the frictional force is sufficient in magnitude to hold the gear train 96 in the engaged position illustrated in FIGS. 3 and 5. Upon release of the fine tuning knob 116, the torsion afforded by the helical spring 110 is effective to return the gear train 96 from the engaged position illustrated in FIGS. 3 and 5 to the disengaged or inoperative position illustrated in FIGS. 2 and 4. If the fine tuning knob 116 is manually rotated in the opposite or counterclockwise direction, the gear train 96 will, of course, again assume an operative position, being pivoted clockwise into engaged relation through the engagement of the hook portion 136 of the actuating plate 122 with the hook portion 132 of the actuating spring 126.

According to another aspect of the present invention, the memory tuning portion 26 is cooperable with a remote control channel selecting means to signal the motor drive portion 24 that the selector shaft 52 has reached the next selected channel position. It is to be understood that, as heretofore described, some of the channels represented by the channel selecting positions of the selector shaft 52 are beyond the range of the television receiving set and it is therefore desirable that the selector shaft 52, when actuated by remote control motor driven means, be effective to pass these channel selecting positions and stop at the next channel selecting position to which the television tuner 20 is preset by the operator to receive a signal. For this purpose, the cam assembly 70 includes a front cam or channel selector plate 150 drivingly connected to the back cam support plate 72 so as to rotate therewith in any convenient manner such as by the plurality of securing pins 152 (FIG. 6). The channel selector plate 150 is provided with a plurality of station selecting openings 154 (FIGS. 8 and 9) corresponding to and aligned with the cam members 80. The cam members 80 are each provided with a channel selecting extension rod or portion 156 which is aligned with its respective opening 154 and which is adapted to be positioned within the corresponding opening 154 to block or fill the opening when the cam member 80 is adjusted outwardly to its limiting position out of engagement with the cam follower element 86 of the memory tuning portion 26. When it is desired that a particular channel selecting position of the selector shaft 52 be effective to signal the motor means 24 to stop rotation of the selector shaft 52 during a motor driven operation thereof, it is merely necessary that the cam member 80 corresponding to the particular channel be adjusted inwardly sufficiently that the channel selecting extension 156 thereof be withdrawn from the station selecting opening 154 in the channel selector plate 150 as indicated in FIG. 9. Such adjustments may conveniently be made through the memory tuning portion 26 as heretofore described, the extension 156 being withdrawn from the opening 154 by initial movement of the fine tuning adjustment afforded by engagement of the cam member 80 with the cam follower elements 86. On the other hand, however, for the particular ones of the channels at which the motor means 24 is to pass up the channel selecting position of the selector shaft 52, the cam member 80 will be adjusted through the memory tuning portion 26 so that the cam member 80 thereof is threaded outwardly until the channel selecting extension 156 of that particular cam member 80 blocks or fills its corresponding opening 154, as illustrated by FIG. 8. Additional rotation of the cam element 80 beyond this outer limiting position is prevented through engagement of an extension 158 from the cam member 80 with a stop 160 on the channel selector plate 150 (FIG. 1).

In order to transmit to the motor drive portion 24 of the television tuner 20 the information relative to the position of the channel selecting extension 156 in the respective opening 154, there is provided switch means, shown generally at 162, FIGS. 7 to 9, and including a switch actuating blade 164 having one end thereof pivotally mounted in an opening in the side wall portion 90 and having an arm 166 at the other end thereof for actuating a pair of switch blades 168 and 170. The switching actuating blade 164 has a cam or detent 172 intermediate its ends adapted to ride on the surface of the channel selector plate 150, as illustrated in FIG. 7, and to fit into the channel selector openings 154 thereof which are not filled by the channel selecting extensions 156 of the cam members 80, as illustrated in FIG. 9. The switch actuating blade 164 is biased against the channel selector plate 150 by a tension spring 174. The switch actuating blade 164 will pivot in response to the engagement of the cam 172 thereon in the station selecting opening 154. However, as best illustrated in FIG. 8, when the cam 172 passes over openings 154 which are filled by extensions 156 of the cam members 80, the switch actuating blade 164 will ride over the end surface of the extensions 156 and will not be responsive to that station selecting opening 154.

In order to transform the pivotal motion of the switch actuating blade 164 into an electric signal transmitted to control the motor means 24, each of the switch blades 168 and 170 is provided with an electrical contact 176 which are normally separated from engagement by an insulating plug 178 carried by the arm 166 and positioned between the blades 168 and 170 when the switch actuating blade 164 is in its de-energized or at rest position with the cam 172 thereof in one of the station selecting openings 154, as illustrated in FIG. 9.

The operation of the switch means 162 is believed to be clear from the above description. However, briefly, with the channel selector shaft 52 at one of the channel selecting positions in which the corresponding cam member 80 is adjusted inwardly for purposes of fine-tuning the channel, the channel selecting extension 156 associated with that cam member 80 will be out of the station selecting opening 154 so that the switch actuating blade 164 is biased to the right, as illustrated in FIG. 9, by the spring 174 with the cam 172 positioned in the opening 154. In this position, the contacts 176 of the switch are separated and the switch is opened. however, rotation of the selector shaft 52 will rotate the channel selector plate 150 so that the cam 172 on the switch actuating blade 164 moves out of the opening 164, the switch actuating blade 164 then pivoting counterclockwise against the return bias of the tension spring 174 so that the insulating plug 178 is moved out of engagement with the switch blades 168 and 170 and the electrical contacts will come into engagement due to the natural resiliency of the switch blades 168 and 170 and the electrical circuit through the switch contacts 176 will be closed. The switch contacts 176 will remain in engagement with the switch means 162 in a closed position until an opening 154 is brought into alignment with the cam 172 on the switch actuating blade 164 which is not filled by an extension 156 on its corresponding cam member 80. At this time, the switch actuating blade 164 will move clockwise under the bias of a spring 174, thereby moving the insulating plug 178 between the switch blades 168 and 170 and separating the electrical contact 176.

In order to automatically rotate the selector shaft 52 in response to an appropriate signal, such as a remote control signal, there is provided the motor drive portion 24 (FIGS. 1 and 10) of the television tuner 20. The motor drive portion 24 includes a thrust type driving motor 190 including a stator pole piece 192 of generally U-shape and having its ends spaced apart forming an air gap. A field winding 194 is positioned on the bight portion of the stator 192. The motor 190 further includes an armature 196 mounted on a drive shaft 198 which is supported between a pair of bearings 200 and 202. The bearings 200 andn 202 are spaced apart a greater distance than the width of the armature 196 so that in the de-energized or inoperative position the armature 196 is biased by a spring 204 toward one of the bearings 202 so as to be off-center or out of line with respect to the pole piece 192 as best illustrated in FIG. 10. As is well known, as initial energization of the field winding 194 produces an end thrust on the armature 196 so that the armature tends to center itself within the stator 192, i.e., the armature 196 will have a side thrust applied to it during energization of the field winding 194 which will move the armature 196 to the left in FIG. 10 against the return bias of the compression spring 204.

In order to transmit the driving torque from the drive shaft 198 of the motor 190 to the main shaft 52 of the television tuner 20, there is provided a gear train shown generally at 206. The gear train 206 includes a pair of housing members 208 and 210 fixedly secured to the end wall 32 of the chassis 28 by a plurality of fastening means such as the studs 212 and housing the gear components hereinafter described. The driving gears of the gear train 206 include a pinion gear 214 keyed or otherwise secured to the channel selector shaft 52 extending within the housing members 208 and 210 and an idler gear assembly 216 operatively engaging the pinion gear 214 and positioned between the housing members 208 and 210 and rotatably mounted on an idler shaft 218 supported at its ends by the housing members 208 and 210. Keyed or otherwise secured to the end of the drive shaft 198 between the housing members 208 and 210 is a drive pinion 220 which, in the inoperative or at rest position of the armature 196, is axially disposed out of engagement with the idler gear assembly 216 but which is adapted to engage the idler gear assembly 216 when the drive shaft 198 moves axially to the left as viewed in FIG. 10, during energization of the field winding 194 so as to drivingly engage the idler gear assembly 216. In this manner the motor 190 is drivingly connected to the selector shaft 52 through the gear train 206 only while the field winding 194 of the motor 190 is energized; when the field winding 194 thereof is not energized, the bias of the spring 204 is effective to axially move the armature 196 to the right as viewed in FIG. 10 so that the drive pinion 220 secured thereon is moved axially out of engagement with the idler gear 216. In this manner, the selector shaft 52 is instantly disengaged from the motor 190 when the power thereto to shut off, and the inertia of the armature 196 cannot carry the shaft 52 past its channel selecting position.

In order to prevent energization of the control circuit for the motor drive portion 24 during a manual rotation of the selector shaft 52 by closure of the switch means 162, there is provided a second switch means shown generally at 230 and fixedly secured to the housing of the motor 190 so as to be actuated by the axial movement of the armature 196 through the drive shaft 198. As illustrated, the switch means 230 includes a stationary switch blade 232 and a movable switch blade 238 having their ends secured in spaced apart electrically isolated relation by an insulator block 244 mounted or otherwise secured to an extension 246 fixedly secured to the housing of the motor 190. The switch blades 232 and 238 are provided with a pair of electrical contacts 248 near their free end which, when the field winding 194 is de-energized, are nromally spaced apart so as to form a normally open switch for the purpose of controlling the motor control portion 24 of the television tuner 20. The movable switch blade 238 is biased to the left as viewed in FIGS. 1 and 7, due to the natural resiliency of the switch blade itself. However, when the armature 196 is in the de-energized position, so that the drive shaft 198 is biased toward the right, the right end of the drive shaft 198 engages the free end of the movable switch blade 238 through an insulating member 254. However, once the armature 196 moves to the left upon energization of the field winding 194, the right end of the drive shaft 198 moves to the left out of engagement with the free end of the movable switch blade 238 and the electrical contacts 248 of the switch means 230 are closed. It will be understood that, immediately upon de-energiztion of the field winding 194, the armature 196 and drive shaft 198 secured thereto move to the right, as viewed in FIGS. 1 and 10, under the bias of the spring 204 and separate the contacts 248 to open the electrical circuit thereto.

The electrical control system for the motor control means 24 is illustrated diagrammatically in FIG. 13. The switch formed by the contacts 176 of the switch means 162 and the switch means formed by the contacts 248 of the switch means 230 are serially connected in series with the motor 190. An impulse type starting switch illustrated generally at 260 and which may consist of a push type switch, is connected across the switch means 162 and 230 so as to shunt across the pair of contacts 176 and 248 when held in its closed position. Momentary closing of the starting switch 260 energizes the field winding 194 moving the armature 196 and drive shaft 198 of the motor 190 to the left, as viewed in FIGS. 1 and 10, closing the contacts 248 of the switch means 230. Immediately upon energization of the field winding 194, a drive torque is applied to the armature 196 which has now moved to the left as viewed in FIGS. 1 and 10 so that the drive pinion 220, which has moved to engage the idler 216, rotates the selector shaft 52. Initial rotation of the selector shaft 52 moves the cam 172 out of the station selecting opening 154 on the channel selector plate 150, pivoting the switch actuating blade 164 so that the insulating plug 178 is moved from between the blades 168 and 170 of the switch means 162, thereby closing the switch formed by the contacts 176. The starting switch 260 may now be released and the electrical circuit to the motor 190 is maintained through the switch means 162 and 230. The cam 172 will ride on the surface of the channel selector plate 150 as illustrated in FIG. 7 and will pass over any of the channel selector openings 154 which are filled with a channel selecting extension 156 of the cam members 80 as illustrated in FIG. 8. However, whenever the channel selector plate 150 has been rotated to a channel selecting position representing a preselected receiving channel, the channel selecting extension of the cam member 80 does not fill the channel selecting opening 154 of the channel selecting plate, and the cam 172 drops in that station selecting opening, as illustrated in FIG. 9, thereby pivoting the actuating blade 164 and opening the contacts 176 to de-energize the field winding 194. Immediately upon de-energization of the field winding 194, the axial thrust on the armature 196 is removed and the armature 196 is moved to the right, as viewed in FIGS. 1 and 7, thereby separating the electrical contacts 248 and rendering the drive connection between the drive pinion 220 and the idler 216 ineffective.

The separation of the electrical contacts 248 prevents energization of the electrical circuits by a manual rotation of the channel selector 52 to a desired channel selecting position. It will be appreciated that initial rotation of the selector shaft 52 manually will cause the cam 172 to rise out of the station selecting opening 154, thereby closing the electrical contacts 176. Under these conditions, the open switch means 230 prevents energization of the motor drive portion of the television tuner 20.

Although the embodiment of FIGS. 1 to 13 illustrates a tuner wherein a single vernier tuning impedance is automatically adjusted to the desired value for each channel selecting position of the selector shaft, it is to be understood that the principles of the present invention are equally applicable to other types of tuners, for example, to a turret tuner of the type illustrated in a copending Krepps et al., application Serial No. 708,594 filed January 13, 1958, wherein individual coil assemblies are provided for each channel, these coil assemblies being removably mounted in a rotatable turret structure. As disclosed in said Krepps et al. copending application, each coil assembly is provided with an oscillator coil the inductance of which may be adjusted by means of a threaded slug which extends into an opening in the end of the coil assembly adjacent the oscillator coil. More particularly, as shown in FIGS. 14 and 15, such a turret tuner 320 comprises a plurality of coil assemblies 335 which are mounted on a plurality of insulating discs 338, one of which is shown in FIGS. 14 and 15, these discs being fixedly secured to the channel selector shaft 340. The television tuner 320 includes a substantially U-shaped chassis 328 having a front wall 332 and a top deck portion 334 on which are mounted the various circuit components. Each of the coil assemblies includes an oscillator coil 342 as well as RF and mixer coils, one of the latter of which is shown at 344, it being understood that the coils on a particular coil assembly are selectively engaged with the contacts of a fixed stator bar (not shown) as the channel selector shaft 340 is rotated to the different channel selecting positions so that the coils on a particular coil assembly are inserted at the appropriate points in the tuner circuit. The oscillator coil 342 is tuned by means of a threaded slug 347 which extends into the end of the coil assembly to a point within the oscillator coil 342. In accordance with the present invention, the slug 347 is provided with a portion 348 which extends out of the end of the coil assembly and carries a pinion gear 350 on the end thereof. The gear 350 may be selectively engaged in a manner described in more detail hereinafter to position the slug 347 and with respect to the coil 342 and hence provide a fine or vernier tuning adjustment for the particular channel corresponding to the particular coil assembly which is being adjusted. It will be understood of course that rotation of each pinion gear 350 will be effective to vary the reactance of each individual oscillator coil 342 on the separate coil assemblies.

In order to provide for manual adjustment of each individually adjustable slug 347 associated with a particular selected channel position, there is provided a gear train represented generally at 352 and the clutch and gear assembly, hereinafter referred to as the clutch assembly, and generally represented at 354. The gear train 352 includes a driven gear 356 and a driving gear 358, each splined or otherwise secured to a shaft 360. The shaft 360 is rotatably mounted near the outer end of the legs of a generally U-shaped bracket 362; the legs of the bracket 362 near the inner end thereof are pivotally mounted on a shaft 364 which may be supported by a bracket 366 extending from the side wall portion 332 of chassis 328. In disengaged or inoperative position, the gear train 352 is biased with the driving gear 358 thereof out of engagement with the pinion gear 350 by a helical spring 368; however, as herein illustrated, the depth of the teeth in the driven gear 356 is sufficiently large so that the driven gear 356 is never fully disengaged from a fine tuning gear 372. The clutch assembly 354 is operative to pivot the gear train 352 into the engaged or operative position illustrated in FIGS. 14 and 15 about the shaft 364 so that the driving gear 358 thereof engages a respective pinion gear 350 integrally formed with the threaded slug 347. Since the threaded slugs 347 are adapted to thread axially in the coil assemblies 335, and therefore axially with reference to the driving gear 358, the face 358a (FIG. 14) of the driving gear 358 has sufficient width to engage the pinion gear 350 throughout its axial movement.

The clutch assembly 354 is identical with the clutch assembly 98 illustrated and described in connection with the embodiment of FIGS. 1 to 13. However, briefly, the clutch assembly 354 is secured to the inner end of a fine tuning shaft 374 mounted for free rotation concentrically about the selector shaft 340. The fine tuning gear 372 is positioned on the fine tuning shaft 374 and is drivingly connected therewith. The outer face of the tuning gear 372 contains a clutch facing 376 bonded or otherwise secured to the tuning gear 372. A fine tuning actuating plate 378 is rotatably mounted on the fine tuning shaft 374 and held against axial movement by a retainer 380. A dish-shaped spring 382 is effective to apply axial pressure between the actuating plate 378 and the tuning gear 372 through the clutch facing 376 so that manual rotation of the tuning gear 372 through the fine tuning shaft 374 is effective to provide a turning torque to the actuating plate 378 through the clutch facing 376; however, the axial load exerted by the spring 382 is small enough that slippage can occur between the actuating plate 378 and the tuning gear 372 when the restraining torque of the actuating plate 378 reaches a predetermined amount.

In order to pivot the gear train 352 about the shaft 364 into its engaged or operative position, so that the driving gear 358 is in engagement with the pinion gear 350, there is provided the generally V-shaped actuating spring 384 which interconnects the gear train 352 and the clutch assembly 354. The actuating spring 384 is identical to the actuating spring 126 in the embodiment of FIGS. 1 to 13 and need not be fully described. However, the actuating spring 384 has a center portion 384a positioned over the shaft 360. Each of the legs of the actuating spring 384 terminates in a hook portion 386. Moreover, the actuating plate 378 is provided with a pair of hook portions 388 which are efective to engage a respective one of the hook portions 386 upon rotation of the actuating plate 378. As heretofore described, initial rotation of the actuating plate 378 is effective to engage one of the hook portions 386 of the actuating spring 384 to pivot the gear train 352 about the shaft 364, for example, from its disengaged or inoperative position to the engaged or operative position illustrated in FIGS. 14 and 15. While the torque transmitted through the clutch facing 376 from the tuning gear 372 to the actuating plate 378 is sufficient to hold the gear train 362 in this operative position, the clutch facing 376 is effective to permit rotation of the tuning gear 372 relative to the actuating plate 378 upon further rotation of the fine tuning shaft 374.

From the above description of the memory fine tuning portion illustrated in FIGS. 14 and 15, the operation of the improved memory fine tuning means is believed clear. However, briefly, in order to rotate a selected one of the threaded slugs 347 relative to its respective coil assembly 335, the fine tuning shaft 374 is manually rotated in the desired direction. As heretofore described it will be appreciated that initial rotation of the fine tuning shaft 374 in either direction will be effective to rotate the actuating plate 378 without slippage so that the hook portion 388 on the actuating plate 378 will engage the hook portion 386 on the actuating spring 384 and will rotate the bracket 362 into the engaged position illustrated in FIGS. 14 and 15. This movement occurs when the tuning shaft 374 is rotated in either direction. Such initial rotation of the fine tuning shaft 374 and pivotal movement of the bracket 362 is effective to bring the driving gear 358 into driving engagement with the pinion gear 350 for the selected one of the channel selecting positions of the selector shaft 340. Continued rotation of the fine tuning shaft 374 will be effective to cause slippage between the shaft 374 and the actuating plate 378 and at the same time will be effective to drive the fine tuning gear 372 in the direction of rotation thereof, thereby to drive the selected one of the pinion gears 350 through the gear train 352 in a manner heretofore described in connection with the embodiment of FIGS. 1 to 13. Moreover, it will be appreciated that the clutch assembly 354 is effective to provide a turning and holding torque on the actuating plate 378 thereby to maintain the gear train 252 in operative relation with the pinion gear 350 so long as the turning torque is applied or held on the fine tuning shaft 374; however the load exerted through the clutch facing 376 is small enough that slippage can occur between the actuating plate 378 and the fine tuning gear 372 when the restraining torque on the actuating plate 378 reaches a predetermined amount.

Moreover, it will be appreciated that the memory fine tuning mechanism illustrated in FIGS. 14 and 15 may be substituted for the memory fine tuning mechanism in the embodiment of FIGS. 1 to 13 and that the system may thereby include a motor drive portion operatively associated with a selector plate similar to selector plate 150 and operatively associated with the gears 350 to provide for motor driving of the selector shaft 340 which is effective to pass certain channel selecting positions and to stop at the next channel selecting position to which the television tuner 320 has been preset by the operator by the axial positioning of the spur gears 350 ot receive a television signal.

The above-described television tuner provides a memory fine tuning arrangement resulting in maximum flexibility of the drive arrangement and of the fine tuning drive means. Moreover, the memory fine tuning of the set is readily adjustable by a viewer from outside the cabinet by the mere rotation of the fine tuning knob concentrically positioned on the channel selector shaft. The memory disc and the independently adjustable fine tuning cam members cooperate to provide desired positioning signals for the automatic shaft rotating mechanism such as for a remote control motor drive.

While certain preferred embodiments of the invention have been described by way of illustration, many modifications will occur to those skilled in the art. It will be understood, of course, that it is not desired that the invention be limited thereto since modifications may be made, and it is, therefore contemplated by the appended claims to cover any such modifications as fall within the true spirit and scope of the invention.



PHILIPS 23TX401A SUPER-ONTVANGER CIRCUIT ARRANGEMENT FOR PRODUCING A SAWTOOTH CURRENT ACROSS THE VERTICAL DEFLECTION COIL OF A TELEVISION RECEIVER, Philips Tubes vertical deflection
A circuit for introducing adjustable parabolic and S-components in a sawtooth curr
ent in a coil, wherein the coil is connected in the output of an amplifier device, con-sists of the series circuit of a charging capacitor, a wind-ing coupled to the coil, and a first resistor. A first series circuit of a second resistor and a reservoir capacitor is connected between the junction of the first resistor and winding and the junction of the winding and charging ca-pacitor, in that order. The junction of the second re-sistor and second capacitor are connected to the control electrode of the amplifier. The other end of the charging capacitor is connected to a variable tapping on a parallel resistance capacitance circuit in another input circuit of the device, in order to permit varying of the relative am-plitudes of the parabolic and S-components. A variable resistor is connected between the control electrode and the variable tapping in order to permit variation of the am-plitudes of the parabolic and S-component with respect to the sawtooth component.

The invention relates to a circuit arrangement for producing a sawtooth current across the vertical deflection coil of a television receiver. The coil is included in the output circuit of the vertical output stage, to the control-electrode of which is applied the sawtooth con-trol-signal which is developed across a charging capacitor included in the control-electrode circuit. The charging capacitor is periodically discharged and is recharged with the aid of a charging circuit which includes the se-ries combination of a resistor and a winding, lying outside the discharging circuit. The winding is magnetically cou-pled with a choke included in the output circuit of the 50 vertical output stage, through which winding a voltage is induced, which is opposite the capacitor voltage. Said winding has connected with it in parallel the series corn-bination of at least one resistor and one reservoir capaci-tor, the free end of the latter being connected to the June- 55 tion of the charging capacitor and the winding. A furher input electrode of the output stage has connected to it the parallel combination of a resistor and a capacitor.
One end of a further resistor is connected to the control electrode of the vertical output stage, and the other end GO of the further resistor is coupled with the resistor con-nected to the said input electrode. Such a circuit arrangement is described in U.S. Patent No. 2,851,632. It is, however, necessary to add to each cycle of the sal,vtooth current one cycle of a parabola 65 component and also one cycle of a so-called &com-ponent. The parabola component is required in view of the fact that the vertical deflection coil is coupled through a trans-former with the vertical output stage. The same applies 70 to the case in which for other reasons than coupling through the transformer not only the vertical deflection
3,426,243 Patented Feb. 4, 1969
coil, behaving substantially like a resistor, but also an in-ductor is included in the output circuit of the vertical final stage. The S-component is required in view of the fact that the display screen of the display tube in a television re-ceiver is flat. Therefore, the rate of deflection of the electron beam must be higher at the centre of the screen than at the edge in order to achieve a linear displacement of the spot on the display screen. The S indicates sym-bolically what form the current through the deflection coil must be for obtaining these desired deflection rates. Numerous circuit arrangements are known by which the desired current form can be produced. However, they have the disadvantage that they are either too compli-cated or are not capable of providing the correct ratio between the sawtooth, parabola and S-component. The circuit arrangement according to the invention is, on the contrary, simple and provides, in addition, the possibility of adjusting accurately the desired ratio between saw-tooth, parabola and S-component, while it prevents, in addition, an excessive influence of undesirable higher de-gree components in the produced current. In order to produce the parabola and S-component, and permit adjustment of their amplitudes, the circuit arrangement according to the invention is characterized in that in parallel with the reservoir capacitor there is con-nected an integrating network which consists of the series combination of an integrating capacitor and an integrating resistor, the free end of the latter being coupled with the junction of the charging capacitor and of the reservoir capacitor. The junction of the integrating resistor and the integrating capacitor is connected to the control-electrode of the output stage. The end of the charging capacitor remote from the winding is connected to a variable tap-ping of the resistor connected to the input electrode. The impedance of the latter resistor is, in operation, great with respect to the impedance of the comparatively great parallel-connected capacitor. In addition, the further re-sistor is made variable, and the end thereof not connected to the control electrode is connected to the tapping of the resistor connected to the input electrode. Variation of the tapping point adjusts the relative ampltiudes of the parab-ola and S-component, while variation of the further resistor controls the relative amplitudes of the parabola and S-component with respect to the sawtooth. A few possible embodiments of circuit arrangements according to the invention will be described with reference to the accompanying figures, of which FIG. 1 shows a possible circuit diagram of an embodi-ment equipped with valves. FIG. 2 shows a partial substitute diagram of the ar-rangement of FIG. I. FIG. 3 shows a further diagrammatical substitute dia-gram of the arrangement of FIG. 2. FIG. 4 shows a first possible modification of the sub-stitute diagram of FIG. 3 and hence of the arrangement of FIG. I and FIG. 5 shows a second possible modification of the substitute diagram of FIG. 3 and hence also of the ar-rangement of FIG. 1. Referring to FIG. 1, the valve 1 is the vertical output stage of a television receiver, the anode circuit of which includes an output transformer 2. The vertical deflec-tion coil 4 is connected to the secondary winding 3 of said transformer 2. In order to produce the desired control-voltage for the control-electrode 5 o
f the valve 1, the grid circuit of said valve includes the following network. This net-work consists in the first place of a charging resistor 6, a winding 7 and a charging capacitor 8, which are connected in series with each other and the free end of the charging resistor 6 is connected to the positive supply voltage +VB. In practice the voltage +VB is usually derived from the horizontal output stage, since this stage is, in the first place stabilised and is, in addi-tion capable of providing a fairly high supply voltage, which is conducive to the linearity of the sawtooth volt-age to be produced. It will be seen from FIG. 1 that the end of the capacitor 8 remote from the winding 7 is connected, in accordance with a first principle of the invention, to a variable tapping 9 associated with a po-tentiometer 10, which is included in the cathode con-ductor of the valve 1. This resistor is shunted by a com-paratively large electrolytic capacitor 11, which is chosen so that its impedance is small for the repetition frequency of the sawtooth voltage to be produced with respect to the impedance of the resistor 10. As is in-dicated by the line 12 with the double arrow, the wind-ing 7 is magnetically coupled with the primary winding of the transformer 2. As is the case in said Patent No. 2,851,632 the sense of winding of the winding 7 is such that the sawtooth voltage 13 produced across the wind- 90 ing 7 is unlike the sawtooth voltage 14 produced across the capacitor 8. Also in this case this serves to ensure an optimum linearity of the sawtooth 14. The winding 7 has furthermore connected with it in parallel the series combination of a capacitor 15 and two resistors 16 and 17, the resistor 17 being variable. The network 15, 16 and 17 is provided for eliminating the peak developed across the winding 7 during the vertical fly-back from the signal 13, so that a signal 18 is finally produced across the capacitor 15, the polarity of this signal being opposite that of the voltage 14 across the capacitor 8, its waveform being, however, substantially identical to that of the latter. For this purpose the capacitor 15 must have a comparatively high value: a value of 68K pf. may be chosen and the resistors 16 and 17 serving as peak resistors must be comparatively small; values of 22K ohms and 10K ohms respectively may be chosen. According to a further aspect of the arrangement ac-cording to the invention the sawtooth voltage 18 is em-ployed for producing partly the required parabola com-ponent and partly the desired S-component. As will be explained more fully hereinafter, this means that fur-ther steps are required to ensure that the control-signal applied finally to the control-electrode 5 accurately con-tains the desired components with their correct ampli-tudes. In order to convert the sawtooth voltage 18 produced across the capacitor 15 into a signal containing the de-sired parabola and S-components, the capacitor 15 has connected with it in parallel the series combination of a capacitor 19, a resistor 20 and a large capacitor 21, operating as a blocking capacitor. The capacitor 21. is un-essential for the further explanation, it only serves to en-sure that the high direct voltage at the junction of the winding 7
and of the charging capacitor 8 cannot pene-trate to the control-grid S. Therefore, the network formed by the capacitor '19 and the resistor 20 constitutes the in-tegration network proper which has to ensure that the voltage V15 produced across the capacitor 15 is converted into a signal containing the desired correction corn-ponents. 'Finally, the third step according to the invention con-sists in that a resistor 22 is arranged between the con-trol-grid 5 and the variable tapping 9. In order to display that, in fact, the control-grid 5 has produced across it the desired control-signal and that by connecting the capacitor 8 and the resistor 22 to the variable tapping 9 the anode current starts passing through the valve 1, which contains all the desired com-ponents for providing accurately the correct waveform of the final current through the deflection coil 4, HG. 2 shows partially a substitute diagram of the arrange-rnent of FIG. 1. It will be apparent from FIG. 2 that the voltage Vg of capacitor 8 is indicated by at and the voltage V15 of capacitor 15 by in a and b are constants, which have each the dimension of a voltage per unit time. It will furthermore be obvious that, since finally the sawtooth voltage to be applied to the control-grid 5 must increase during the forward stroke, the number of turns of the winding 7 has to be chosen so that the amplitude of the signal 13, as far as the sawtooth por-tion is concerned, is smaller than the amplitude of the signal 14 and it follows therefrom that for the signal 18 V, ith respect to the signal 14 the same must apply. It therefore always applied a>b. For performing the desired calculation the circuit dia-gram of FIG. 2 is further simplified and shown in this form in FIG. 3. In .FIG. 3 the capacitor 15 is represent-ed by a voltage source 15', which supplies a voltage v15,. The capacitor 8 is represented by a source 8', which supplies the voltage Vg. The capacitor 21. is omit-ted from the diagram of FIG. 3, since it is large and un-essential for these explanations. It is furthermore as-sumed in the diagram of FIG. 3 that the source 15' pro-duces a current i1 through the network of the capacitor 19 and the resistor 20 only, whilst the sources 8' and 15' produce a current i2, which passes through the ca-pacitor 19 and resistor 22.

The greater the time constants R20C19 and R22C19 are 70 chosen, the small become the values of Pi and 132. Since, moreover, the denominator increases with an increas-ing degree in t (for t4 the denominator is 24 and for /3 it is already 120), the fourth and higher degree terms in Equation 5 can be neglected with respect to the first, 75 second and third degree terms with a correct choice of the resistors R20 and R22 and of the capacitor 19.

This signal contains, in principle, all the desired correction terms, since it contains not only the linear term, i.e. the sawtooth component (a—b)t but also the posi-tive quadratic term, i.e. the required parabolic component and a negative third-degree term, i.e. the component re-quired for the S-correction. This S- or third-degree com-ponent must, in fact, be negative, since with respect to 15 the flat display screen of the display tube the rate of scanning must be reduced both at the beginning and at the end of the stroke. This means a third-degree term must be subtracted from the linear term.
Since a>b, it follows therefrom that the positiveness of this coefficient depends upon the ratio between R20 and R22. On the basis of a positive term, it becomes constantly smaller according as R22 diminishes until it changes over from positive to negative, which means that by means of •R22 in a first instance the measure of parabolic correction and the measure of S-correction can be adjusted In principle, the desired extent of parabolic correction with respect to the sawtooth component could be adjusted, but this does not apply to the associated extent of S-cor-rection, since the terms pi and g2 occur in the parabolic component in the first power and in the S-component in the second power. Since the fl-values are small, the S-corn-ponent is smaller than the parabolic component. If the p values are raised, the S-component may be increased with respect to the parabolic component until the desired ratio between the parabolic and S-components is attained, after which without changing this ratio the two corn-ponents can be simultaneously decreased by varying R22 relatively to R20 to their desired values relative to the sawtooth component. By increasing the fl-values, how-ever, the negligence of the higher-power terms in Equa-tion 6 is no longer permissible. The control-signal will therefore contain not only the desired sawtooth, parabolic and S-components but also an excess of undesirable 4th, 5th and even higher power terms. This means that the increase in the values of g is re-stricted so that the desired ratio between the parabolic and S-components cannot be adjusted in this manner. According to the principle of the invention negative feedback is used apart from the introduction of the nega-tive sawtooth source V15= —bt and the parallel connec-tion therewith of the network R20r19, The anode current is of the valve 1 can be indicated by ia=S(Vi—aVic), wherein S is the mutual conductance of the valve 1, and VK is the cathode voltage thereof.
In the known circuit arrangements of Patent No. 2,851,632 the part of the arrangement for the production of the sawtooth and cor-rection voltages comprises four capacitors and five resis-tors. In the arrangement according to the invention five capacitors and six resistors are required. In principle, we are concerned with a different arrangement of a substan-tially equal number of parts, the values of which have to be chosen carefully or which have to be variable. In the foregoing the fact is left out of consideration that the voltage V15 obtained from the winding 7 contains not only a linear term —bt but also second- and third-degree components, since the anode current i a, which induces a voltage in the winding 7, contains second- and third-degree terms. However, if the value of p, is chosen correctly, it can be said that the influence of the third- and fourth-degree terms in vo,tage V15 with respect to the linear term is negligible. An exact calculation can, of course, be made, in which all factors also the negative feedback through the winding 7 are considered. The formulae then obtained are, however, so compli-cated that it is difficult to make conclusions therefrom. In the explanation given above, it is therefore preferred to use an approximate calculation, which has the advantage of providing a good insight in the operation of the circuit arrangement. So far the function of the triode 23 has been left out of consideration, since it is not connected with the prin-ciple of the invention. This triode only serves for a periodi-cal discharge of the capacitor 8. To this end the signal derived from the output transformer 2 is applied through a further secondary winding 24 and various capacitors and resistors to the control-grid of the valve 23. The signal derived from the winding 24 has the same waveform as the signal 13 and ensures that during the fly-back the triode 23 gets into the conducting state, so that the capac-itor 8 is discharged. The terminals 24' and 25 receive frame synchronising pulses which provide a direct syn-chronisation of the valve 23. It appears therefrom that the oscillator circuit formed by the valves 1. and 23 is of the so-called trnultivibrator type, in which, however, the feed-back of the anode of the valve 1 to the control grid of the valve 23 is performed through the output transformer 2. It will be obvious, however, that any other control-method for valve 23 may be employed. The valve 23 may be formed by a blocking oscillator, so that this valve in itself is included in an independent oscillator circuit which provides a periodical discharge of the capacitor 8. The advantage of the arrangement of FIG. I is however, that a separate blocking transformer is economised, whilst only the winding 24 suffices for obtaining a self-oscillating circuit. It is neither strictly necessary for the deflection coil 4 to be connected through the winding 3 of the transformer 2 to the anode of the valve 1. When the impedance of the de-flection coil 4 allows so, it may be connected through a capacitor cutting off the direct current to the anode of the valve 1. In this case the primary winding of the trans-former 2 can be considered to be a choke with which the secondary winding 7 is magnetically coupled. The wind-ing 24 may, if desired, also be coupled with said choke, if a transformer arrangement of the multivibrator type is desired, or the winding 24 may be omitted, and the valve 23 may be formed by a blocking oscillator. Particularly, if transistors are used instead of valves, it is common practice to couple the vertical deflection coil 4 directly with the collector electrode of the output transistor.It will be obvious that with the use of transistors all parts of the arrangement of FIG. I remain the same and that the operation is quite identical. In the calculations it is indifferent whether valves or transistors are employed. Possible modifications of the arrangement of FIG. I may be explained with reference to FIGS. 4 and S. FIG. 4 shows the resistor 22 connected, instead of being con-nected between the control-grid 5 and the tapping 9, to the earth-connected end of the resistor 10. This mode of connection brings about scarcely any difference with re-spect to the A.C. effect from that of FIG. 3, but with re-spect to the D.C. adjustment of the valve 1 there is some difference. In the case of FIG. 3 the D.C. bias voltage of the control-grid 5 will follow the displacement of the tapping 9. In the arrangement of FIG. 4 this is not the case. It will be obvious that this modification also holds good without the need for further means for the arrange-ment of FIG. I, since only the end of the resistor 22 re-mote from the control-grid 5 has to be connected to earth. A further possible modification is shown in FIG. 5. In parallel with the source 8' there is connected a poten-tiometer resistor 27, provided with a variable tapping 26. The end of the resistor 22 remote from the control-grid 5 is connected to the tapping 26. This modification operates accurately like that of FIG. 3, which may be explained as follows. It is assumed that the variable tapping 26 is dis-placed towards the connection with the variable tapping 9. Then the same arrangement is obtained as that of FIG. 3 and therefore the operation is therefore quite identical. If, however, the tapping 26 is displaced towards the junc-tion of the sources 8' and 15', the resistor 22 is in parallel with the resistor 20 and the operation of the arrangement of FIG. 5 will be accurately the same as that of FIG. 3, if resistor 22 had an infinite value. This means that in Equation 6 the factor 02=0 and that both the quadratic and S-components will assume maximum values. It will be seen that the displacement of the tapping 26 from the junction of the sources 8' and 15' towards the tapping 9 brings about an attenuation of the parabolic and of the S-components. It can therefore be said that the displace-ment of the tapping 26 in the said direction has the same effect as a decrease of the resistor 22 in the arrangement of FIG. 3. The modification of FIG. 5 may be realised in the ar-rangement of FIG. I by providing a potentiometer 27 with a tapping 26 in parallel with the capacitor 8 and by connecting the end of the resistor 22 remote from the control-grid 5 to the tapping 26. It should be noted that the resistance value of the potentiometer 27 should not be too high, since it should not effect too strongly the value of the factor p2• What is claimed is: 1. A circuit for producing a sawtooth waveform cur-rent in a coil, comprising: an amplifier device having an output electrode, and first and second input electrodes, output circuit means for coupling said output electrode to said coil, a charging capacitor, a discharging circuit connected to said charging capaci-tor for periodically discharging said charging capacitor, a charging circuit for charging said charging capacitor and comprising a first series circuit connected in series with said charging capacitor, said first series circuit comprising a serially connected winding and first resistor means, means coupling said winding to said output circuit to provide a voltage across said winding opposing the charging capacitor voltage, a second series circuit of a first capacitor and second resistor means, means connecting said second series circuit in parallel with said winding, with one end of said first capacitor being connected to one end of said charging ca-pacitor, a third series circuit comprising a second capacitor and third resistor means connected in that order between the junction of said first capacitor and second resistor means and said one end of said charging capacitor, means connecting the junction of said second capacitor and third resistor means to said first input electrode, a parallel circuit comprising a third capacitor and fourth resistor means connected in parallel with said third capacitor, the impedance of said fourth resistor means being large with respect to the impedance of said third capacitor at the operating frequency, means connecting said parallel circuit between said sec-ond input electrode and a point of reference potential, and means connecting the other end of said charging capacitor to a tap on said fourth resistor means. 2. A circuit for producing a sawtooth waveform cur-rent in a coil, comprising: an electron discharge device having an anode, a cathode, and a control grid, output circuit means for coupling said coil to said anode, a source of potential having first and second terminals, a charging capacitor, 25 means connected to said charging capacitor for peri-odically discharging said charging capacitor, a charging circuit for said charging capacitor compris-ing a winding and first resistor means connected in that order between one end of said charging capacitor 30 and said second terminal, means coupling said winding to said output circuit to provide a voltage across said winding opposing the charging capacitor voltage, a first series circuit of a storage capacitor and second 35 resistor means connected in parallel with said winding with one end of said storage capacitor being con-nected to said one end of said charging capacitor, a second series circuit of an integrating capacitor and integrating resistor, means connecting said second series circuit in parallel with said storage capacitor, with one end of said integrating capacitor being connected to the other end of said storage capacitor, means connecting the other end of said integrating ca-pacitor to said control grid, a parallel circuit of potentiometer means and a capaci-tor connected in parallel with said potentiometer means, the impedance of said potentiometer means being large with respect to the impedance of said parallel capacitor at the operating frequency, means 'connecting said parallel circuit between said cathode and first terminal, and means connecting the other end of said charging capacitor to a tap on said potentiometer means. 3. The circuit of claim 2, in which said output circuit comprises a transformer having a primary winding con-nected to said anode and a secondary winding coupled to said coil, wherein said first-mentioned winding is a tertiary winding of said transformer. 4. The circuit of claim 2, comprising variable resistor means connected between said control grid and said tap. S. The circuit of claim 2, comprising variable resistor means connected between said control grid and said first terminal. 6. The circuit of claim 2, comprising a second potenti-ometer means connected in parallel with said charging capacitor, and resistor means connected between said con-trol grid and the tap on said second potentiometer means.


TUBES USED:

- EF184
- PCF80
- EF184
- EF183
- PCF80
- PCF86
- PCC189
- DY87
- PC86
- PC88
- PL500
- PY81
- PCL84
- PCL86
- PCL85
- ECH84
- PCF802
- PCL85
- PF86
- ECH84
- PCF80
- PCF80



Constant potential transformer / Constant Voltage transformer :

 The old B/W Tubes Television set was powered with a External Voltage stabiliser / Constant Voltage transformer unit (portable metal box) because  There was intermittent significant rapid line voltage dips here and there that were rather annoying when watching a tube set with an unregulated power supply (like all tvs of ancient times) and it eliminates the line dip issue completely.


(The, of mine, Pictured Constant Voltage transformer unit taken as example is a "KURTIS" STV/3 Italian Manufactured in Milan (Italy) in Year 1954 with a 250 VA power displacement and developed under Italian Patent 50499. It's clearly reported that input may be universal within -20%  +10% variations, output is precisely regulated within 1% range.........................click on pictures to enlarge them at full screen......)

The invention relates to voltage regulators of the type employed to supply alternating current and a constant voltage to a load circuit from a source in which the line voltage varies. They are particularly advantageous in connection with commercial applications such as amplifiers for talking motion pictures, amplifiers for radio transmitters,  Television sets (tubes),   mercury arc lamps, X-ray apparatus, etc.







 
Features : Instantaneous Voltage regulation. No effect of input Transient and spikes on the output. Sinusoidal output waveform. Was a  perfect answer and remedy for all types of electronic equipment. The  CVT have been designed to give you total protection against power related problems and to condition the power to suit the needs of Tubes television sets based equipment. It effectively regulates voltage variation, suppresses transients and bridges short interruptions/dips.

Basics: Ferro Resonant type Constant Voltage Transformers - CVT, the AC mains power the input winding, which The input winding normally runs at very moderate Flux linkage levels. The output winding exhibits an intrinsic energy characteristic and this energy storage operate in conjunction with mains capacitor to produce self-generated AC flux Field which is indirectly extracted from the Input Winding.
These Constant Voltage transformer or CVT use a tank circuit composed of a high-voltage resonant winding and a capacitor to produce a nearly constant average output with a varying input. The ferroresonant approach is attractive due to its lack of active components, relying on the square loop saturation characteristics of the tank circuit to absorb variations in average input voltage.

The ferroresonant action is a flux limiter rather than a voltage regulator, but with a fixed supply frequency it can maintain an almost constant average output voltage even as the input voltage varies widely.

All problems related to variation / fluctuation in Voltages are effectively handled because of this principle and a constant voltage output of ± 1% is given.


 INVENTOR: JOSEPH G. SOLA.

The  invention relates to an improved constant potential transformer by means of which variations of input voltage over a wide range of limits may take place without affecting the output voltage to any substantial extent.

One of the objects of my invention is to provide a constant potential transformer which is compact as a unit and which may be economically manufactured.

o1 It is another object of my invention to provide a transformer of this type in which the efficiency and input power factor are high while the temperature rise of the magnetic core is low.

A further object of my invention is to provide 1., a transformer, the outputvoltage wave of which will have very little distortion and the device will be satisfactory for various commercial applications.

The invention consists of the novel constructions, arrangments and devices to be hereinafter described and claimed for carrying out the above stated objects and such other objects as will appear from the following description of certain preferred embodiments illustrated in the accompanying drawings, wherein,Fig. 1 is a sectional view of one form of construction that may be used; Fig. 2 is a diagrammatic illustration of the wiring arrangement that may be used in connection with a construction such as that shown in Fig. 1; Fig. 3 is a sectional view of another form of construction embodying the principles of my invention; Fig. 4 is a diagrammatic illustration of the wiring arrangement that may be used in connection with a construction such as that shown in Fig. 3; Fig. 5 is a diagram showing the vector relations between the various voltages obtained in the illustrated constructions at different values of input voltage; and Fig. 6 is a graph showing the relation between the magnitudes of various voltages obtained in the illustrated constructions as the input voltage is varied.

Like characters of reference designate like parts in the several views.

Referring to Figs. 1 and 2,
it will be seen that a core type of transformer construction is illustrated, the closed magnetic circuit 10 of which comprises a stack of I-shaped laminations II in abutting relation with the end legs 12a of a stack of E-shaped laminations 12, which may be held 5 together by any suitable means. On the end portion A of the core bar 11, I have provided a primary winding 13, the terminals 14 and 15 of which are adapted to be connected with a source of alternating current, the voltage of which from time to time may fluctuate or vary substantially. g On the end portion B of the core bar 11, I have mounted a winding 16, which is in spaced relation to but magnetically coupled with the winding 13, the winding 16 having terminal leads 17 and 18 and an intermediate tap 19. That part of the winding 16 between the lead I7 and tap 19 may be considered as an output or load winding, and the entire winding 16 between the leads 17 and 18 may be termed an intermediate winding.

The magnetic core 10 is provided with a high leakage reactance path between the windings 13 and 16 which in the form shown comprises the central leg 12b of the E-shaped laminations and which terminates short of the core bar 1 thereby providing a non-magnetic or air gap 20 between said leg 12b and the core bar II. In this arrangement, a condenser 21 is connected by leads 22 across the terminals 17 and 18 of the winding 16.

The lead 17 forms one side and the tap 19 the other side of what may be termed an output or load circuit. In the arrangement shown, an auxiliary winding 23 is positioned over the winding 13 and is magnetically coupled therewith, the terminals 24 of said winding 23 being connected in series in the lead 19 of said output circuit. In Figs. 3 and 4, I have illustrated my invention in connection with a well-known shell type of transformer having two closed magnetic circuits 10 and 10a comprising a straight central core bar 25 of I-shaped laminations, the sides of which are in abutting contact with the end legs 26a of the E-shaped laminations 26 and the end legs 27a of the E-shaped laminations 27, said parts being held in operative relation by any suitable means. On the end portion A, of the core bar 25, I have mounted a primary winding 28 the terminals 29 and 30 of which are adapted to be connected to a source of alternating current, the voltage of which may fluctuate substantially from time to time. Another winding 31 is positioned on the end portion B of the core bar 25, the winding 31 being in spaced relation to but magnetically coupled loosely with the winding 28.

A condenser 32 is connected across the terminals 33 and 34 of the winding 31. Another winding 80 35 is mounted on the end portion B of the core bar 25, in the arrangement shown the winding 35 being positioned over and magnetically coupled tightly with the winding 31. The terminal 36 of the winding 35 leads to one side of what may i be termed an output circuit. An auxiliary winding 37 is positioned on the end portion A of the core bar 25 and in the arrangement illustrated the winding 3I is positioned over and magnetically coupled tightly with the winding 28.


A lead 38 connects the winding.37 in series with the winding 35, the lead 39 of the winding 37 forming the other side of the aforesaid output circuit. The winding 35 may be termed an output or load winding and the winding 31 may be considered as an intermediate winding. The closed magnetic circuits described are each provided with a high leakage reactance path between the windings 28 and 37 on the end portion A of the core bar 25 and the windings 31 and 35 on the end portion B of said core bar, which in the arrangement shown comprise the central legs 40 and 41 of the respective E laminations 26 and 27. The shunts 40 and 41 terminate short of the adjacent sides of the core bar 25 thereby providing non-magnetic or air gaps 42 and 43 between the legs 40 and 41 and the core bar 25.

In Figs. 2, 4, 5 and 6 Vo represents the voltage across the output circuit, Vp shows the input voltage on the primary winding, Vs indicates the voltage derived from the winding 16 between the lead 17 and tap IS, and from the winding 35 forming parts of the respective output circuits, and Vpa is the component of the output voltage taken across the terminals of the auxiliary winding 23 or 31, as the case may be.

In Fig. 5, I have shown the vector relations of the various voltages in either arrangement at a certain power output and at different values of primary voltage. The various voltages are either not primed or are primed to correspond to the different values of Vp which is varied. As shown, Vpa is nearly 180* out of phase with Vs, and hence the vectorial sum Vo of the two is approximately their numerical difference.

In Fig. 6, I have illustrated graphically the relation in the constructions described between Vs, Vo, Vpa and Vp ata certain power output.

The principles upon which my improved transformer constructions operate will be clear from a detailed consideration of the construction shown in Figs. 3 and 4. The flux set up by applying a potential across the primary winding 28 will link with winding 31 and cause a definite reactance to be set up by that winding. As the voltage on the. primary winding is increased from zero to a higher level, the flux threading through winding 31 tends to increase in nearly direct proportion to the primary flux, due to the re5 luctance caused by the air gaps 42 and 43, a very slight amount leaking through the shunts 40 and 41. As the Induced E. M. F. reaches a higher value in winding 31 a critical point is reached where resonance takes place, since the reactance of the effective inductance of the winding 31 and the capacity reactance of the condenser 32 are approximately equal at the frequency of the voltage impressed on the winding 28. that is to say.

WCfL where f is the frequency of the voltage impressed on the primary winding 28, L is the effective 70 Inductance of the winding 31, and C is the capacity of the condenser 32. Under this resonant condition, a definite amount of current will flow in the resonant circuit, comprising the winding 31, condenser 32 and leads 33 and 34, and such t6 current will be limited by the constants of that circuit, with the result that a potential will be set up across the winding 31 and a corresponding amount of magnetic flux will be set up in the end portion B of the core bar 25.

It is well known that the inherent characteristic of a resonant ci
rcuit is such that its power vector may be many times greater than that of the generator which supplies the energy to the resonant circuit; in this case the energy is supplied by the primary of the transformer to the resonant circuit comprising winding 31 and condenser 32. By varying the primary voltage across winding 28 so that the magnetic density of section A thereof will still remain under the maximum magnetic density of section B of the core, with which the resonant circuit is associated, the change of flux density in section A of the core due to line variation in the primary will have no appreciable effect on the resonant circuit as the reluctance of the leakage path will be under that of section B of the core and flux will leak through the leakage path between the primary and resonant core portions, which leakage path comprises the shunts 40 and 41 and their respective nonmagnetic gap portions 42 and 43. It is due to this leakage reactance path also that the co-efficient of coupling between the primary winding 28 and the aforesaid resonant circuit is reduced to a certain optimum value, thereby maintaining a balanced condition so that the resonant circuit will continue to oscillate with the maximum current therein at a frequency equal to the frequency impressed on the primary winding. Under this state of resonance, winding 31 will set up a magnetic field in the core portion B which will remain practically constant so long as the density in the magnetic field of the core portion A remains at a lower density than that of the core portion B. It follows that this substantially constant field strength in core portion B will produce also a substantially constant voltage across the terminals of winding 31 and condenser 32, and this voltage will remain at practically a constant level regardless of variation of voltage applied to the primary winding 28. The aforesaid resonant circuit, therefore, becomes a constant primary source of voltage for any winding such as the winding 35 that is directly coupled to the winding 31. This coupling can be effected in any desired way, for example, by means of an auto-type transformer arrangement as shown in Fig. 2, or by mounting the winding 35 over the winding 31 as shown in Fig.

4. In the Fig. 4 construction, the output voltage of the windings 35 will also have a practically 5, constant level voltage independent of the voltage variation in the primary winding 28 so long as the circuit which includes the winding 31 remains in resonance.


The auxiliary regulating winding 37 is coupled go to the portion A of the core and is used to change the percentage of regulation of Vo across the terminals 36 and 39 of the output circuit with a variation of Vp. Since this auxiliary winding 37 on core portion A is directly coupled to the pri- 05 mary winding 28, the voltage induced will always be proportional to the turns ratio of primary winding 28 and the auxiliary winding 37.

A very constant level of voltage Vo across the terminals 36 and 39 may be obtained by suitably T0 apportioning the number of turns of said auxiliary winding 37 in relation to the number of turns in the winding 35. Any percentage of regulation of output voltage in relation to variations of Vp also may be obtained from terminals Ts 2 t ist. .y 36 and 39,-for example, an increase in the prinrary voltage on winding 28 will produce a decrease in output voltage Vo by properly arranging or apportioning winding 37 in relation to the winding 35.

The relation of voltages described has been upon the assumption that the transformer is on an open output circuit, that is to say, with no load on the terminals 36 and 39. If a load be applied on said terminals, a magnetic flux in the aforesaid resonant circuit will be developed corresponding to the load on said output circuit thereby unbalancing the magnetic flux in section B of the core. This density change in core section B will in turn affect the stable relation of the flux in core sections A and B and also the leakage reactance through the aforesaid shunt paths thereby causing a greater amount of useful flux from core section A to thread through core section B, which compensates for the energy used by the consuming circuit and at the same time maintains the resonant circuit in the desired oscillating condition.

It will be readily understood that in transformers embodying the principles of my invention the primary winding electrically connected to the source serves to induce voltage to the resonan
t circuit which is separated from the primary circuit by a high leakage reactance path, thereby providing a low co-efficient of coupling between the primary and the resonant circuits. The aforesaid resonant circuit may be considered as the primary or main source of controlling energy to the winding 35 and hence'to o3 the output or consuming circuit of the transformer.

My improved constant potential transformers are compact and efficient, and are of a small size relative to their power output as compared with other and more cumbersome and expensive apparatus intended for the same purpose. My improved transformers operate at an inherent high power factor, and the output voltage is very close to a pure sine wave.

My improved transformers may be used for many different purposes. They are particularly advantageous in connection with commercial applications such as amplifiers for talking motion pictures, amplifiers for radio transmitters,  Television sets (tubes),   mercury arc lamps, X-ray apparatus, etc.

I wish it to be understood that my invention is not to be limited to the specific constructions shown and described, except so far as the claims may be so limited, as it will be apparent to those skilled in the art that changes in the constructions and arrangements may be made without departing from the principles of my invention.

I claim:1. In a constant potential transformer, the combination of a magnetic core, a winding on said core adapted to be connected to a source of alternating current of fluctuating voltage, a second winding on said core, said core providing a high leakage reactance path for a portion of the flux to thread through one of the windings to the exclusion of the other winding, and means for maintaining the potential across the second winding substantially constant regardless of fluctuations in the input voltage comprising a resonant circuit including said second winding and a condenser, the resonant circuit operating at a frequency equal to the frequency of the voltage impressed on the first winding.

2. In a constant potential transformer, the 7T combination of a magnetic core, a winding on said core adapted to be connected to a source of alternating current of fluctuating voltage, a second winding on said core in spaced relation to said first winding, said core having magnetically disposed between said windings a magnetically 6 permeable shunt with a non-magnetic gap portion, and means for maintaining the potential across the second winding substantially constant regardless of fluctuations in the input voltage comprising a resonant circuit including said second winding and a condenser, the resonant circuit operating at a frequency equal to the frequency of the voltage impressed on the first winding.

3. In a constant potential transformer, the combination of a closed magnetic circuit comprising first and second core portions, a winding on said first core portion adapted to be connected to a source of alternating current of fluctuating voltage, a second winding on said second core portion, said circuit providing a high leakage reactance path for a portion of the flux to thread through one of the windings to the exclusion of the other winding, and means for maintaining the potential across the second winding substantially constant regardless of fluctuations in the input voltage comprising a resonant circuit including said second winding and a condenser, the resonant circuit operating at a frequency equal to the frequency of the voltage impressed on the first winding, the magnetic density at maximum predetermined input voltage of the first core portion being less than the maximum magnetic density of the second core portion.

4. In a constant potential transformer, the 85 combination of a closed magnetic circuit comprising first and second core portions, a win
ding on said first core portion adapted to be connected to a source of alternating current of fluctuating voltage, a second winding on said second core portion in spaced relation to said first winding, said circuit having magnetically disposed between said windings a magnetically permeable shunt with a non-magnetic gap portion, and means for maintaining the potential across the second winding substantially constant regardless of fluctuations in the input voltage comprising a resonant circuit including said second winding and a condenser, the resonant circuit operating at a frequency equal to the frequency of the voltage impressed on the first winding, the magnetic density at maximum predetermined input voltage of the first core portion being less than the maximum magnetic density of the second core portion.

5. A constant potential transformer comprising in combination a magnetic core, a primary winding on said core adapted to be connected to a source of alternating current of fluctuating voltage, a load winding on said core adapted to be connected to an output circuit, said core providing a high leakage reactance path for a portion of the flux to thread through one of the windings to the exclusion of the other winding, and means for maintaining the potential across the load winding substantially constant regard- 05 less of fluctuations in the input voltage comprising a resonant circuit including a condenser and a third winding, the resonant circuit operating at a frequency equal to the frequency of the voltage impressed on the primary winding, the third winding being in inductive relation to the load winding.

6. A constant potential transformer
comprising in combination a magnetic core, a primary winding on said core adapted to be connected to a source of alternating current of fluctuating voltage, a load winding on said core in spaced relation to said primary winding and adapted to be connected to an input circuit, said core having magnetically disposed between said winlings a magnetically permeable shunt with a non-magnetic gap portion.; and means for maintaining the potential across the load winding substantially constant regardless of fluctuations in the input voltage comprising a resonant circuit including a condenser and a third winding, the resonant circuit operating at a frequency equal to the frequency of the voltage impressed on the primary winding, the third winding being in inductive relation to the load winding.

7. A constant potential transformer comprising in combination a closed
magnetic circuit comprising first and second core portions, a primary winding on said first core portion adapted to be Sconnected to a source of alternating current of fluctuating voltage, a load winding on said second core portion and adapted to be connected to an output circuit, said magnetic circuit having magnetically disposed between said windings a magnetically permeable shunt with a non-magnetic gap portion, and means for maintaining the potential across the load winding substantially constant regardless of fluctuations in the input voltage comprising a resonant circuit including a conSdenser and a third winding, the resonant circuit operating at a frequency equal to the frequency of the voltage impressed upon the primary winding, the third winding being on the second core portion and in inductive relation to the load winding, the magnetic density at maximum predetermined input voltage of the first core portion being less than the maximum magnetic density of the second core portion.

8. A constant potential transformer comprising in combination a magnetic core, a primary wind40 ing on said core adapted to be connected to a source of alternating current of fluctuating voltage, a load winding on said core adapted to be connected to an output circuit, said core providing a high leakage reactance path for a portion of the 45 flux to thread through one of the windings to the exclusion of the other winding, a resonant circuit including a condenser and a third winding, the resonant circuit operating at a frequency equal to the frequency of the voltage impressed on the 50 primary winding, the third winding being in inductive relation to the load winding, and an auxiliary winding on the core in inductive relation to the primary winding and in series with the load winding, for the purpose described.

55 9. A constant potential transformer comprising in combination a closed magnetic core comprising first and second core portions, a primary winding on said first core portion adapted to be connected to a source of alternating current of fluctuating 60 voltage, a load winding on said second core portion and adapted to be connected to an output circuit, said core having magnetically disposed between said windings a magnetically permeable shunt with a non-magnetic gap portion, a reso65 nant circuit including a condenser and a third winding, the resonant circuit operating at a frequency equal to the frequency of the voltage impressed on the primary winding, the third winding being in inductive relation to the load winding, and an auxiliary winding on said first core portion in inductive relation to the primary winding and in series with the load winding, the magnetic density at maximum predetermined input voltage of said first core portion being less thain the maximum density of said second core portion.

10. A constant potential transformer comprising in combination a magnetic core, a primary winding on said core adapted to be connected to a source of alternating current of fluctuating voltage, a second winding on said core provided with two leads and an intermediate tap, one of said leads and said tap leading to an output circuit, said core providing a high leakage reactance path for a portion of the flux to thread through one of the windings to the exclusion of the other winding, and means for maintaining in said output circuit a substantially constant potential regardless of fluctuations in the input voltage cornprising a resonant circuit including a condenser connected in series between the leads of said second winding, the resonant circuit operating at a frequency equal to the frequency of the voltage impressed on the primary winding.

11. A constant potential transformer comprising in combination a magnetic core; a primary winding on said core adapted to be connected to a source of alternating current of fluctuating voltage; a second winding on said core provided with two leads and an intermediate tap; said core having magnetically disposed between said windings a magnetically permeable shunt with a non-magnetic gap portion; and means for maintaining in said output circuit a substantially constant potential comprising a resonant circuit ineluding a condenser connected in series between the leads of the second winding, the resonant circuit operating at a frequency equal to the frequency of the voltage impressed on the primary winding, and an auxiliary winding on said core in 40 inductive relation to the primary winding and in series with the load winding.
12. A constant potential transformer comprising in combination a closed magnetic core comprising first and second core portions; a primary 45 winding on said first core portion adapted to be connected to a source of alternating current of fluctuating voltage; a second winding on the second core portion and provided with two leads and an intermediate tap; one of said leadsandsaidtap 50 leading to an output circuit; said core having magnetically disposed between said windings a magnetically permeable shunt with a non-magnetic gap portion; the maximum density at maximum predetermined input voltage of said first 55 core portion being less than the maximum density of said second core portion; and means for maintaining in said output circuit a substantially constant potential comprising a resonant circuit including a condenser connected in series between 60 the leads of the second winding, the resonant circuit operating at a frequency equal to the frequency of the voltage impressed on the primary winding, and an auxiliary winding on said core in inductive relation to the primary winding and o5 in series with the load winding.

JOSEPH G. SOLA.


Transformer having constant and harmonic free output voltage

This invention relates to voltage transforming and regulating apparatus, and to core and coil constructions therefor, more particularly to such apparatus having a substantially harmonic free output voltage, and it is an object of the invention to provide improved apparatus and constructions of the character indicated.

It is a further object of the invention to provide improved apparatus of the character indicated having an output voltage which is substantially constant irrespective of variations of input voltage over a certain range, and which is substantially free of harmonics.

It is a further object of the invention to provide an improved transformer.

To provide a source of alternating current voltage of a desired frequency which is free of harmonics, that is, a sine wave, has long been a problem because of the undesired eifects produced thereby. For example, instruments which receive a voltage having harmonics therein may give erroneous and sometimes erratic indications. Apparatus supplied with a voltage having harmonies therein may overheat, and its useful life may be lessened. If the transformer which is supplying a voltage is responsible for the generation of harmonics, the supply transformer as well as the apparatus connected to it may overheat.

Commercial power systems supplying alternating current voltage approach the desired condition of a harmonic free voltage, and a large amount of technical eifort is devoted thereto. However, even with the extensive attention directed to this problem, it frequently occurs, in industrial areas particularly, that the supply voltage has an undesired percentage of harmonics.

In the Patent No. 2,143,745, Joseph G. Sola, entitled Constant Voltage Transformer, there is disclosed and claimed apparatus including a transformer and a condenser wherein a substantially constant output voltage is obtained throughout a certain range of variation in input voltage. While the output voltage of apparatus constructed according to the said patent has good wave form, that is, one largely free of harmonics, under certain conditions the voltage output has included as much as five per cent of third harmonic.

Filter circuits which are connected between the output of a source and a load and which serve to substantially reduce or eliminate harmonics are known. Such filters generally require the use of additional condensers and inductors and will correct the output voltage only when load current is flowing. Moreover, the correction may depend upon the amount of the load, there being the greatest correction at full load and substantially none at no load.

Accordingly, it is a further object of the invention to provide an improved transformer which will provide a constant output voltage substantially free of harmonics, which does not require additional condensers or inductors, and which will substantially eliminate the harmonics from no load to full load.

It is a further object of the invention to provide an improved transformer of the character indicated which will have improved efficiency in operation and which is economical to manufacture.

In carrying out the invention in one form, a transformer is provided having substantially constant output voltage and a substantially harmonic free output voltage and comprising in combination, a core, a primary winding and a secondary winding on the core, a high reluctance shunt magnetically disposed between the primary 2,694,177 Patented Nov. 9, 1954 and secondary windings, a third winding disposed on the core in a position to link with a portion of the leakage flux of the secondary winding and to be substantially free of any linkage with the leakage flux of the primary winding, a condenser which is connected in circuit with the secondary winding and the third winding, the condenser having a value of capacity such that when the transformer is excited with a voltage of predetermined magnitude and frequency a condition of a series resonant nature exists at that frequency, and means for connecting a load circuit to a certain portion of the secondary winding.

For a more complete understanding of the invention, relilferfince should be had to the accompanying drawings in w to Figure 1 is a sectional view of a transformer core and coils according to one form of the invention, and

Figure 2 is a diagrammatic representation of a system according to the invention and employing the core and coils of Fig. 1.

Referring to Figs. 1 and 2 of the drawing, the invention is shown embodied in regulating apparatus including a core and coil arrangement 10 having input, output, regulating and compensating windings and a condenser 11 connected to certain of these windings, all to be more particularly described.

The core and coil arrangement 10 comprises a core 12 which may be made of laminations stamped in the form shown and made of suitable material such, for example, as 26 gauge transformer C steel. The core, as shown, is composed of laminations or layers, each of which consists of two pieces, and when assembled into a stack of desired thickness form an outer piece or shell 13 and a center leg 14. The outer shell includes a pair of end legs 6 and 7 and a pair of side legs 8 and 9. The laminations of center leg 14 may be stamped from the pieces forming the outer shell 13 as part of the same process during which the openings or coil windows 15, 16, 17, 18, 19 and 21 are also formed. A core of the proper thickness is formed by assembling together the required number of outer shell laminations and pressing into the appropriate space the same number of center leg laminations assembled together, as is well understood in this art.

Each lamination of the outer shell 13, as shown, comprises a complete or continuous piece of metal with no joints therein. It will be understood, however, that the same configuration can be made up of individual pieces if so desired. Projecting inwardly from leg 8 between the coil windows 16 and 17 is a member 22 formed of the corresponding parts of the laminations of shell 13, and projecting inwardly from leg 9 between coil windows and 18 is a member 23 also formed of the corresponding parts of the laminations of shell 13. Projecting inwardly between coil windows 17 and 21 is a member 24 formed of parts of the laminations of shell 13, and projecting inwardly between coil windows 18 and 19 is a member 25 also formed of the corresponding parts of the laminations of shell 13. Projecting outwardly from the center leg 14 are members 26 and 27 formed of corresponding parts of the center leg laminations and so disposed as to lie between the coil windows 15 and 18 and 16 and 17 and to be disposed opposite the members 23 and 22, respectively, when the center leg 14 is disposed in shell 13 with the right end thereof forming the joint 28.

The members 22 and 27 are spaced from each other by a nonmagnetic gap 29, and the members 23 and 26 are spaced from each other by a nonmagnetic gap 31. The members 24 and 25 are formed of such a length as to tightly abut the center leg 14 at the joints 32 and 33 and have a cross-sectional area substantially less than that of the end leg 7 of the outer shell 13. The center .leg 14 is formed of a length so as to tightly abut the outer shell at joint 28 at one end and to leave a nonmagnetic gap 35 between the other end of the center leg and the inside surface of end leg 7.

Coil windows 15 and 16 comprise a space within which a primary winding 36 and a compensating winding 37 are disposed; coil windows 17 and 18 form a space within which a secondary winding 38 is disposed;

and coil windows 19 and 21 comprise a space within which a neutralizing winding 3% is disposed. Each of the coils or windings 36, 3'7, 38 and 39 comprise an appropriate number of turns and are provided with sufficient insulation, as is shown schematically in Fig. 1. Each of the coils may be preformed and placed upon the center leg and the unit pressed into the outer shell so as to form the nonmagnetic gap 35 and the abutting joints 23, 32 and 33.

The members 22 and 27 and gap 29, and members 23 and 26 and gap 31, form a high magnetic leakage path between the primary winding 36 and the secondary winding 38. The width of the members 22, 27, 23 and and the length of the nonmagnetic gaps 23 and 31 are chosen so as to provide the desired amount of magnetic leakage reactance, as will become clear subsequently in this specification. While the members 22 and 2'7 and gap 29, and members 23 and 26 and gap 31, as shown, form a high magnetic leakage pathway, it will be understood that the high magnetic leakage pathway may be formed in other well understood manners.

The members 24 and 25, the end of leg 14 together with the end leg 7 and the nonmagnetic gap 35 complete the end path for magnetic flux generated by the primary winding. Since the joints 32 and 33 are press-fits, there is little magnetic reluctance thereat, and consequently the members 24 and 25 form a return path which carries the major portion of the primary flux. These mom bers, however, are formed narrower than the end leg 7 whereby a small percentage of the primary flux flows through the end leg 7. The nonmagnetic gap 35 produces high reluctance in the path of the primary flux, thereby reducing the amount of flux which would flow through leg 7 if the gap were not there, and increasing the percentage of primary flux which flows through members 24 and 25.

The structure as thus far described in Fig. l is illustrated diagrammatically in Fig. 2, the same reference characters being used in the two figures to designate corresponding parts. Thus the windings 36 and 38 are disposed on a common core with a high leakage reactance shunt 22, 27, 29, 23, 26, and 31 disposed therebetween, winding 39 is disposed on the same magnetic core with the nonmagnetic gap 35 separating the core parts, and winding 3'7 is disposed in a closely coupled relationship to winding 36.

The effect of the high leakage path between primary winding 36 and secondary winding 38 is to relatively loosely couple these windings so that each of the windings has a high leakage reactance, and nonmagnetic gap 35 tends to isolate the winding 39 from the flux of the primary winding.

The primary winding 36 is adapted to be connected to a line or source by conductors 41 and 42. The secondary winding 38 has one of its ends connected by means of a conductor 43 to one terminal of condenser ll, and has its other end connected by means of a conductor 44 to one end of neutralizing winding 39 by a conductor 45. The other end of neutralizing winding 3% is connected by means of a conductor 46 to the other terminal of condenser 11. The conductors 44 and 45 connected together may be connected to one side of a load circuit through a conductor 47, and the other side of the load may be connected through a conductor 48 to one end of a compensating winding 37, the other end of which is connected by means of a conductor 49 to a tap on the secondary winding 38. The load circuit may then be traced as follows: From one side of the load through conductor 47, conductor 44, the right-hand portion of winding 38, conductor 49, winding 37, and conductor 43 to the other side of the load.

The operation of the apparatus may perhaps best be understood by considering its operation in two phases; that is, as a constant voltage apparatus alone, and as the combination of the constant voltage and the harmonic elimination or neutralizing apparatus. Considering first the constant potential aspects of the apparatus, it may be made such in one form by removing, in efiect, the neutralizing winding 39. Referring to Fig. 2, this may be accomplished by connecting conductor 46 to conductors 44 and 47 and disconnecting conductor 45 from conductors 44 and 47. When so connected, the apparatus of Figs. 1 and 2 is essentially similar to the form of the apparatus illustrated in the Patent No. 2,143,745, already hereinbefore referred to. When connected in this form as only a constant potential device,

the members 24 and 25, together with leg 7, form a portion of the return circuit for the primary winding flux and provide a return leg having substantially the same elfgctgive cross section as the other flux return legs 8 an For a complete understanding of the operation of the device in this form as a constant voltage transformer, reference may be had to the aforesaid Patent No. 2,143,745. Briefly, however, when voltage above a certain magnitude is applied to the primary winding 36 through conductors 41 and 42, a condition approximating series resonance is set up in the apparatus, and particularly in the circuit including condenser 11 and winding 38. When this condition exists, a substantially constant voltage is obtained across conductors 4'7 and 49 over a wide range of variations in voltage applied to the primary winding. Such small changes as occur in this voltage may be compensated for by the winding 37 which is closely coupled to winding 36 and which is in such a relation as to buck the voltage existing across conductors 47 and 49. Thus, if the primary voltage rises and the output voltage would tend to rise on account thereof, the compensating winding prevents it. Likewise, if the primary voltage falls and the output voltage tends to fall, the bucking voltage is also reduced and the output voltage remains the same. By proper choice of turns of winding 37, the load voltage, that is, the voltage appearing across conductors 47 and 48, is made substantially constant.

Vvhile explanation of the operation of this form of the device as a constant potential apparatus does not lend itself to simple terms, it is thought that the currents flowing in the condenser 11 and winding 38, due to the existing resonance condition, set up a llux condition in the portion of the core underneath and directly associated with the winding 38, due to the presence of the shunts between the primary and secondary windings 36 and 38, such that changes in flux caused by changes in voltage across the primary winding are largely absorbed in the shunts and thus do not change the flux conditions of the secondary winding. The output voltage or" the device as a constant voltage transformer has good wave shape, but it does have appreciable percentages of harmonies in it which are eliminated by the presence of the neutralizing winding 39. When the device is operating as a constant voltage apparatus and the winding 39 is present in the core but is not connected to the circuit, the winding 39 will, of course, have a voltage induced into it since a certain percentage of flux will course through the center leg 14 and through the end leg 7. With the core constructed as shown and described, it has been found that the voltage of coil 3? has a high percentage of odd harmonics in it, that is, third, fifth, seventh and ninth, etc. There is also present a certain value of fundamental since the winding 39 is linked by a small percentage of the flux set up by the primary winding. The presence of the odd harmonic voltages in winding 39 is due to the linkage of winding 39 by the leakage flux created by winding 38 when current flows through the condenser 11 and winding 33. This leakage flux, of course, has two pathways to follow, one of these including a portion of the central leg 14, the members 24 and 25, a portion of the legs 8 and 9 of the core,

. which links with winding 39, that is, that portion of these windings prior to such connection.

the secondary leakage flux which flows across gap 35 and through leg 7. The leakage flux of the primary winding 36 flows largely through the shunts 22, 27, 29 and 23, 26, 31 and thus does not link with winding 39. Consider now the second phase of the device. The winding 39 is connected in circuit with and in additive polarity to winding 38 and with condenser 11 as shown, to form a constant voltage and harmonic free device. When so connected the combined voltage of windings 38 and 39 is increased over the sum of the voltages of With the con nections so made, the percentage of odd harmonics existing in the winding 38 and across the conductors 47 and 49 is very much reduced and a constant voltage output also is had. They are, in fact, reduced to a virtually negligible amplitude. After. the connection has been made, as shown in Fig. 2, the harmonic voltage still '5 exists across winding 39 and also across the condenser 11, but these harmonic voltages are of such phase that they neutralize the harmonics which formerly existed in the Winding 38. For example the third harmonic, which exists in winding 39, is induced therein by the leakage flux from Winding 38, and this harmonic voltage is approximately 180 out of phase with the third harmonic voltage existing in winding 38.

With winding 39 connected into circuit in additive polarity, there has been, in effect, a number of turns added to the secondary winding, but these turns and the core configuration produce harmonic elimination and do not destroy the constant voltage. The flux in the core remains such that the condition of a series resonant nature still exists and hence substantially constant volt age exists across Winding 38. In order to have the proper value of output voltage with the higher voltage available when winding 39 is connected in circuit with winding 38 in additive polarity, the number of turns of winding 38 may be less than in a construction having only constant voltage output of the same value.

The number of turns in winding 39, the cross-sectional area of members 24 and 25, the length of gap 35, and the cross-sectional area of leg 7 enter into the magnitude of the third harmonic voltage produced as compared with the fundamental voltage in winding 39. The fundamental component is not essential since winding 38 may have a sufficicnt number of turns to produce the necessary value thereof, and it is thought that by coupling the winding 39 to the winding 38, as shown, the necessary .third harmonic neutralizing voltage is obtained while at the same time the fundamental voltage is not changed much.

Reduction of the harmonic voltages, and consequently currents in winding 38, reduces the heating of the windings and of the iron thereby making the transformer itself more eificient and economical, this being an advantage in addition to the desirable effects due to the lack of harmonics in loads.

By way of additional and more complete disclosure, one form of apparatus which was constructed and op; erated may be particularly described. This apparatus had a continuous rating of 500 volt amperes, a rated primary (across conductors 41 and 42) voltage range of 90 to 125 volts, a rated load voltage (across conductors 47 and 48) of 115 volts, and a rated load current of 4.35 amperes. In this apparatus the primary winding 36 had 106 turns of No. 13 copper wire arranged in 10 layers of 11 turns per layer, the winding 37 had 12 turns of No. 14 copper wire arranged in one layer of 12 turns, the secondary winding 38 had 405 turns of No. 15 copper wire arranged in 14 layers of 29 turns each, and the winding 39 had 207 turns of No. 15 copper wire arranged in 23 layers of 9 turns each. That portion of winding 38 lying between conductors 44 and 47, that is, the load portion of the winding, had 290 turns arranged in 10 layers.

The core of the apparatus described was designed to operate at a flux density of 100,000 lines per square inch and consisted of a stack of laminations 3 inches thick of No. 26 gauge transformer C steel. The length of side legs 8 and 9 was 6 inches and the length of end legs 6 and 7 was 5 inches; the width of end leg 6 and side legs 8 and 9 adjacent windings 36 and 38 was /8 of an inch; the width of side legs 8 and 9 adjacent winding 39 and the width of end leg 7 was /8 of an inch; the width of members 24 and 25 was A of an inch; the width of center leg 14 inside of coils 36 and 38 and members 24 and 25 was 1% inches, and the width of leg 14 inside of coil 39 was of an inch; the width of shunt members 22, 27, 23 and 26 was /2 of an inch; the length of gaps 29 and 31 was 0.050 of an inch; and the length of gap 35 was 0.150 of an inch. The width of center leg 14 inside of coil 39 may be the same as inside of coil 38 and the number of turns in coil 39 changed to fit the different space of windows 19 and 21.

The condenser 11 had a capacity of 16 microfarads and was rated at 660 volts.

By way of further disclosure, the results of a harmonic analvsis on the foregoing apparatus. as described and particularized, may be summarized. The first analysis was made at no load; that is, there'was no load connected across conductors 47 and 48. The winding 36 was connected to a sine wave generator supplying 115 volts R. M. S. A harmonic analysis of the sine wave generator voltage indicated that 'the voltage supplied to winding 36 had a fundamental component (60 cycles) of arbitrarily assigned amplitude equal to 100 per cent, and a third harmonic of 1.1 per cent of the fundamental, the remaining harmonics being less than one per cent of the fundamental and consequently negligible. With this same connection, the R. M. S. voltage across condenser 11, that is, across combined windings 38 and 39, was 610 volts. The harmonic analysis of this voltage showed on the basis of a fundamental of arbitrarily assigned amplitude equal to per cent, a third harmonic having an amplitude of 7 per cent, and a fifth harmonic having an amplitude of 2 per cent all in terms of the fundamental. The voltage across the winding 39 had an R. M. S. amplitude of 122 volts. The harmonic analysis showed on the basis of a fundamental of arbi trarily assigned amplitude equal to 100 per cent, a third harmonic having an amplitude of 100 per cent, a fifth harmonic having an amplitude of 20 per cent, a seventh harmonic having an amplitude of 4 per cent, and a ninth harmonic having an amplitude of 17 per cent, all in terms of the fundamental. The voltage across winding 38 had an R. M. S. amplitude of 522 volts, the harmonic analysis showing on the basis of a fundamental of arbitrarily assigned amplitude equal to 100 per cent, a third harmonic having an amplitude of 1.1 per cent, a seventh harmonic having an amplitude of l per cent, and a ninth harmonic having an amplitude of 1.8 per cent, all in terms of the fundamental. Correspondingly, the voltage across that portion of winding 38 between conductors 44 and 49 (load winding) had an R. M. S. amplitude of 127 volts, the harmonic analysis showing on the basis of a fundamental of arbitrarily assigned amplitude equal to 100 per cent, a third harmonic having an amplitude of .4 per cent, a fifth harmonic having an amplitude of .6 per cent, a seventh harmonic having an amplitude of 1.2 per cent, and a ninth harmonic having an amplitude of 1.6 per cent, all in terms of the fundamental. The output voltage, that is, the voltage across conductors 47 and 48, had an R. M. S. value of 114 volts with the harmonic analysis showing on the basis of an arbitrarily assigned fundamental component having an amplitude equal to 100 per cent, a third harmonic having an amplitude of .4 per cent, a fifth harmonic having an amplitude of .7 per cent, a seventh harmonic having an amplitude of 1.3 per cent, and a ninth harmonic having an amplitude of 1.7 per cent, all in terms of the fundamental.

The percentage of harmonics at the load conductors 47 and 48 is of the same general order as that of the applied voltage, the third harmonic being an improvement and some of the higher harmonics being very slightly increased.

In the apparatus as described and for the harmonic values given, when the conductor 46 was connected to the conductor 44, that is, the winding 39 was removed from the circuit as previously described, and the same sine wave generator was connected to the winding 36, the voltage across winding 36 had an R. M. S. amplitude of 115 volts. A harmonic analysis thereof showed on the basis of a 6D cycle or fundamental component arbitrarily assigned an amplitude of 100 per cent, a third harmonic having an amplitude of .8 per cent, a fifth harmonic having an amplitude of .4 per cent, and a seventh harmonic having an amplitude of .3 per cent, all in terms of the fundamental. The voltage across condenser 11 or across winding 38 had an R. M. S. amplitude of 467 volts, the harmonic analysis showing on the basis of a fundamental component of 100 per cent, a third harmonic having an amplitude of 23 per cent, and a fifth harmonic having an amplitude of 6 per cent, all in terms of the fundamental. The portion of winding 38 forming the load winding, that is, the winding connected across conductors 47 and 49, had an R. M. S. amplitude of 113 volts, the harmonic analysis showing on the basis of a fundamental component arbitrarily assigned an amplitude of 100 per cent, a third harmonic having an amplitude of 23 per cent, and a fifth harmonic having an amplitude of 6 per cent, all in terms of the fundamental. Under these conditions, the output voltage, that is, across conductors 47 and 48, had an R. M. S. amplitude of 100 volts, the harmonic analysis showing on the basis of a fundamental component arbitrarily assigned an amplitude of 100 per cent, a third harmonic having an amplitude of 27 per cent, a fifth harmonic having an amplitude of 7 per cent, and a seventh harmonic having an amplitude of one per cent, all in terms of the fundamental. The voltage across winding 39 had an R. M. S. amplitude of 73 volts, a harmonic analysis showing on he basis-of a fundamental componen arbitrarily assignedau amplitude f 100. per cent. a-third harmonic havin an amplitude of 11.00, per cent, a fifth harmoni havingan amplitudeof .78 per cent, a sev nth harmonic having an amplitude; of percent, an a ninth harmonic having an amplitude'of 6 per cenhall in terms of the fundamental.

A compari n f he rela ive harmonic val es across conductors a7 and 43 with the condenser c nnected to include the winding 39 andto exclude it, reveals. the reduction in the harmonic content' t? he output vol age.

A m lar h rmonic a alysis was. made with the apparatus opera ng at full loa with th sin wavesource as alr adyescrib providing l.15 volts acros he primary winding 36. With, the condenser 11 connected s shown in F gthe output volt ge across conductors 47 and cent, a third harmonic having an amplitude of 1-1 per cent, a fifth harmonic having an arriplittldev of .4 per cent, a seventh harmonic having an amplitude of 1.6 percent, an a ni th h rmonic having an amplitude of 1.2 p r. cent. These harmonic values are not substa tially diiferent from those taken at no load. Under the full load condition described, the voltage across winding 3,9had an R. M. S. amplitude of 111 volts, the harmonic analysis showing on the basis of a fundamental component arbitrarily assigned an ampltiude of 100 per cent, a third harmonic-having an amplitude of ,98 per cent, a fifthv harmonic having an amplitude of 16 per cent, a seventh harmonic having an amplitude of ll per cent, and a ninth harmonic having an amplitude of 11 per cent, all in terms of thefundamental- The vol age across Condenser 11 had an R. M. S. value of 593 volts with the harmonic analysisshowing n the basis of a fundamental component arbitrarily assigned an amplitude of 100 per cent, a third harmonic having an amplitude of 13 per cent, a fifth harmonic having an amplitude of 1.5 per cent, a seventh harmonic having an amplitude of .2 per cent, and a ninth harmonic having an amplitude of .1 per cent, all in terms of the fundamental. The voltage across winding 38'had an R. M. S. amplitude of 512 volts, the harmonic analysis show ing a fundamental component arbitrarily assigned an amplitude of 100 per cent, a third harmonichaving an amplitude of 1.7 per cent, a fifth harmonic having an amplitude of zero per cent, a seventh harmonic having an am.- plitude of 1.4 per cent, and a ninth harmonic having an amplitude of 1.2 per cent.

With full load being supplied by the transformer, and i with the condenser 11 connected so as to-remove wind.- ing .39 from the circuit,-tha.t is, conductor connected to conductor 44, the output voltage across conductors 4.7. and 48 had an R. M. S. amplitude of '97 volts, the harmonic analysis showing on the basis of a fundamental component arbitrarily assigned an amplitude of 10.0 per cent, a third harmonic having an amplitude of 23 per cent, a fifth harmonic having an amplitude of 6 per cent, and a seventh harmonic haying'an amplitude of .Tper cent. The voltage of winding 3.8 or condenser 11 had an, R. M. ,S. amplitude of 452 volts, the harmonic analysis showing a fundamental component arbitrarily assigned an amplitude of .100 per cent, a third harmonic having an amplitude of '20 per cent, a fifth harmonic having ah amplitude of per cent, and a seventh harmonichaving an amplitude of ,4 per cent. Comparing the relativeharlmonic value between the-full load condition where-in the neutralizing winding 39 is connected into and out .of the circuit, reveals that the harmonic content is very much by the presence of winding 39 in the core structure defined.

The loads fed by the transformer in the preceding tests were resistance loads.

"The structure as shown in Fig. 2 and having the harmonic analysis as given, was connected to a re ular The. in en on ha ing h s be descr ed, Wha is el imedandde re to. be s cur d by L e s. a nt s:

A transformer having substantially costant output voltage and a substantially armonic free voltage comprising, a core, a primary winding and a secondary winding on said core, ahigh reluctance shunt magnetrc l v disposed t eens d v nd ngs, a con e av ng a value of capacity such that when'connected across said secondary winding and the transformer is excited with a voltage of predetermined magnitude and frequency a condition of a seriesresonaut nature exists at the said freq v, a third ind ng d pos d n sa d ore n a P tion to link with a portion ofthe leakage flux of said secondary Windingand to be substantially free of any linkage with the leakage flux of said primary winding, said secondary winding, said third winding and said condenser being connected in circuit, and means for connecting a load circuit to at least a certain portion of said secondary winding.

2. A transformer having substantially constant output voltage and a substantially harmonic free output voltage comprising, a core, a primary winding and a secondary winding on said core, a high reluctance shunt magnetically disposed between said windings, a condenser having a value of capacity such that when connected across said secondary winding and the transformer is excited with a voltage of predetermined magnitude and frequency a condition of a series resonant nature exists at the said frequency, a third winding disposed on said core in a positionto link with a portion of the leakage flux of said secondary windingand to be substantially free of any linkage with the leakage flux of said primary winding, said secondary winding, said third winding and said condenser being connected in circuit with said third winding in additive polarity to said secondary winding, a compensating winding disposed on said core in close coupled relationship with said primary winding and connected in b ng r lat onship to saidse ary nd ng. and means for connecting a load circuit to at least a certain portion of said secondary winding and to said compensating winding,

A ns m ha ing suhstantia yc nst toutput voltage and a substantially harmonic free output voltage comprising, a core, a primary winding and a secondary winding on said core, a high reluctance shunt magnetically disposed-between said windings, a condenser having a value of capacity such that when connected across said secondary winding and the transformer is excited with a voltage of predetermined magnitude and frequency a condition-of a series resonant nature exists at the said frequency, a harmonic eliminating winding disposed on said core in a position to link with a portion of the leakage flux'of said secondary winding and to be substantially free of any linkage with the leakage flux of said primary winding, said secondary winding, said harmonic eliminating winding and said condenser being connected in circuit, and means for connecting a load circuit to at least a certain portion of said secondary winding.

4. A transformer having substantially constant output voltage and a substantially harmonic free output voltage comprising, a core, a primary winding and a secondary winding on said core, a high reluctance shunt magnetically disposed between said windings, a condenser having a value of capacity such that when connected across said secondarywinding and the transformer is excited with a voltage of predetermined magnitude and frequency a condition of a series resonant nature exists at the-said frequency, a third w'mding disposed on said core in a position to link with a portion of the leakage flux of said secondary winding and to be substantially free of any linkage with the leakage flux of said primary winding, saidse'condary winding, saidthird winding and said condenser being connected in a series circuit with said third winding in additive polarity relative to said secondary winding, and means for connecting a load circuit to at least a certain portion .of said secondary winding.

5- A n o m h in subs ant ally con tant ou pu voltage an a substanti l y harmonic free output lt ge mpr sing, a c e, a pr ary Winding and a se nd ry in g o said co e, a hi h re uct n s un ma c ly d posed be ween a d i di s, .a cond se having a alu o apac y such t a h n e ted a r ss sai se da y in ing. and he t an former is excited with a voltage of predetermined magnitude and frequency a condition of a series resonant nature exists at the said frequency, a thir:l winding disposed on said core, the leakage flux path of said third winding including a portion having low reluctance and a portion having high reluctance to the fluxes of said primary and secondary windings, said secondary winding, said third winding and said condenser being connected in circuit, and means for connecting a load circuit to at least a certain portion of said secondary winding.

6. A transformer having substantially constant output voltage and a substantially harmonic free output voltage comprising, a core, a primary winding and a secondary winding on said core, a high reluctance shunt magnetically disposed between said windings, a condenser having a value of capacity such that when connected across said secondary winding and the transformer is excited with a voltage of predetermined magnitude and frequency a condition of a series resonant nature exists at the said frequency, a third winding on said core, a low reluctance shunt magnetically disposed between said third winding and said primary and secondary windings, and high reluctance means disposed in the flux path of said third winding, said secondary winding, said third winding and said condenser being connected in circuit, and means for connecting a load circuit to at least a certain portion of said secondary winding.

7. A transformer having substantially constant output voltage and a substantially harmonic free output voltage comprising, a core, a primary winding disposed on one leg of said core, a secondary winding disposed on said one leg, said primary and secondary windings being relatively loosely coupled thereby to provide said windings with high leakage reactance, a condenser having a value of capacity such that when connected across said secondary winding and the transformer is excited with a voltage of predetermined magnitude and frequency a condition of a series resonant nature exists at the said frequency, a third winding on said one leg, at low reluctance shunt disposed between said third winding and said secondary winding, high reluctance means in said core beyond said shunt, and means for connecting a load circuit to at least a certain portion of said secondary winding.

8. A transformer having substantially constant output voltage and a substantially harmonic free output voltage comprising, a core, a primary winding disposed on one leg of said core, a secondary winding disposed on said one leg, said primary and secondary windings being relatively loosely coupled thereby to provide said windings with high leakage reactance, a condenser having a value of capacity such that when connected across said secondary winding and the transformer is excited with a voltage of predetermined magnitude and frequency a condition of a series resonant nature exists at the said frequency, a third winding on said one leg, a low reluctance shunt disposed between said third winding and said secondary winding, high reluctance means in said one leg beyond said shunt, and means for connecting a load circuit to at least a certain portion of said secondary winding.

9. A transformer having substantially constant output voltage and a substantially harmonic free output voltage comprising, a core, a primary winding disposed on one leg of said core, a secondary winding disposed on said one leg, said primary and secondary windings being relatively loosely coupled thereby to provide said windings with high leakage reactance, said high leakage reactance means including a magnetic shunt having a nonmagnetic gap, a condenser having a value of capacity such that when connected across said secondary winding and the transformer is excited with a voltage of predetermined magnitude and frequency a condition of a series resonant nature exists at the said frequency, a third winding on said one leg, a low reluctance shunt disposed between said third winding and said secondary winding, high reluctance means in said core beyond said shunt, said high reluctance means including a core portion and a nonmagnetic gap, and means for connecting a load circuit to at least a certain portion of said secondary winding.

10. A transformer having substantially constant output voltage and a substantially harmonic free output voltage comprising, a core, a primary winding and a secondary winding on said core, a high reluctance shunt magnetically disposed between said windings, a third winding disposed on said core in a position to link With a portion of the leakage flux of said secondary winding and to be substantially free of any linkage with the leakage flux of said primary winding, a condenser, said secondary winding, said third winding and said condenser being connected in circuit, said condenser having a value of capacity such that when the transformer is excited with a voltage of predetermined magnitude and frequency a condition of a series resonant nature exists at the said frequency, and means for connecting a load circuit to at least a certain portion of said secondary winding.

ll. A transformer having substantially constant output voltage and a substantially harmonic free output voltage comprising, a core, a primary winding and a secondary winding on said core, a high reluctance shunt magnetically disposed between said windings, a third winding disposed on said core in a position to link with a portion of the leakage flux of said secondary winding and to be substantially free of any linkage with the leakage flux of said primary winding, a condenser, said third winding in additive polarity to said secondary winding and said condenser being connected in circuit with said secondary winding, said condenser having a value of capacity such that when the transformer is excited with a voltage of predetermined magnitude and frequency a condition of a series resonant nature exists at the said frequency, and means for connecting a load circuit to at least a certain portion of said secondary winding.

12. A transformer having substantially constant output voltage and a substantially harmonic free output voltage comprising, a core, a primary winding and a secondary winding on said core and having high leakage reactance associated therewith, a condenser having value of capacity such that when connected across said secondary winding and the transformer is excited with a voltage of predetermined magnitude and frequency a condition of a series resonant nature exists at the said frequency, a third winding disposed on said core in a position to link with a portion of the leakage flux of said secondary winding and to be substantially free of any linkage with the leakage flux of said primary winding, said secondary winding, said third winding and said condenser being connected in a series circuit with said third winding in additive polarity relative to said secondary winding, and means for connecting a load circuit to at least a certain portion of said secondary winding.

13. A transformer having substantially constant output voltage and a substantially harmonic free output voltage comprising, a core, a primary winding and a secondary Winding on said core, said primary and secondary windings being relatively loosely coupled thereby to provide said windings with high leakage reactance, a condenser having a value of capacity such that when connected across said secondary winding and the transformer is excited with a voltage of predetermined magnitude and frequency a condition of a series resonant nature exists at the said frequency, a third winding disposed on said core in a position to link with a portion of the leakage flux of said secondary winding and to be substantially free of any linkage with the leakage flux of said primary winding, said secondary winding, said third Winding and said condenser being connected in circuit with said third winding in additive polarity to said secondary winding, and means for connecting a load circuit to at least a certain portion of said secondary winding.

14. A transformer having substantially constant output voltage and a substantially harmonic free output voltage comprising, a core, a primary winding and a secondary winding on said core, said primary and secondary windings being relatively loosely coupled thereby to provide said windings with high leakage reactance, a condenser having a value of capacity such that when connected across said secondary winding and the transformer is excited with a voltage of predetermined magnitude and frequency a condition of a series resonant nature exists at the said frequency, a third winding disposed on said core in a position to link with a portion of the leakage flux of said secondary winding and to be substantially free of any linkage with the leakage flux of said primary winding, said secondary winding, said third winding and said condenser being connected in circuit with said third winding in additive polarity to 11 said secondary Winding, a compensating winding disposed on said core in close coupled relationship with said primary winding and Connected in bucking relationship to said secondary winding, and means for connecting a load circuit to at least a certain portion of said secondary Winding and to said compensating Winding.



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