UTC Classic Grade transformer info please ?

[w1dwz]

There must be some Old Buzzard out there that has an old  UTC catalog  , so that I can rescue this old   CG-126  filament transformer  .  Need the pinout  diagram.   Pretty much isolated the  primaties but the secondary pins have me scratching my head.   tks fer any help.   73  Dave W1DWZ    401 297-0361          w1dwz@fullchannel.net        Bristol RI

[wa3dsp]

Does this help - page 47 - http://www.junkbox.com/electronics/utc_transformer_catalog_1963.pdf

It don't think it shows a diagram but does state the secondary voltages.

[w1dwz]

tks om... Yup  , I found that   file  , but  I am  confused about  the useage of all the pins. There are 20 of them  !     6 for the  primary(s)    and 7 each for the 2 identical secondaries.   And not sure just how they are  assigned due to the slight voltage differences.....  little baffling...   tu fer responding    73 Dave  W1DWZ

[wa3dsp]

How about this link -

http://www.vintageradio.com/history/UTCData.pdf

[w1dwz]

Thanks for trying, Old Man    !  Close but no cigar. I  scanned through the file 3 times to make sure but the  CG-126 was not there.  Driving me crazy and I am not comfortable even  putting full  120 VAC on the pins that I THINK are the correct ones  . I am sure phasing issues  are involved to depending on how UTC splits up the primaries for 110 /  115  / 120  / 220  etc..... tks agn !  73  DWZ

[Steve - K4HX]

Don't put 120 on it. Use a variac or a filament tranny and put something like 5, 6.3 or 10 volts on it. Meter check to your heart's content!

[wa3dsp]

It looks like this is a round case transformer? There should have been a diagram printed on it but I guess it is long worn off.

This transformer has 105,115,210,220,250 primary and six connections. You should be able to ohm it out and find the low 105,115 vs high inputs. Sometimes they had crazy multiple jumpering but if every primary pin has resistance to each other then it might just be a common and a step through the voltages at each consecutive pin.

[w1dwz]

Don't put 120 on it. Use a variac or a filament tranny and put something like 5, 6.3 or 10 volts on it. Meter check to your hearts content!

Yup. That's what I have been doing , Steve.  Been putting  18VAC on what I THINK is the 110 volt winding.   (     about   1/6 of  normal   voltage )    so  shud get   1/6  of secondary voltage , right  ??.  Nope.  Not exactly ,  due to the operating flux density is way below what it shud be and creates a non-linearity in  input / output    voltage ratio  at  the  low flux density  value .   And the very low DC resistances of the   120 VAC windings are a challenge to my ohmmeter !  So I am really scuffling to find some sort of  factory  documentation.   thanks for response.  Dave W1DWZ

[w1dwz]

It looks like this is a round case transformer? There should have been a diagram printed on it but I guess it is long worn off.

This transformer has 105,115,210,220,250 primary and six connections. You should be able to ohm it out and find the low 105,115 vs high inputs. Sometimes they had crazy multiple jumpering but if every primary pin has resistance to each other then it might just be a common and a step through the voltages at each consecutive pin.

Yes, it is that big heavy round case.  And the nice steel stamped  Classic Grade label is there but a paint job has obscured any schematic.   The primary pins are in  2 
ISOLATED  groups of 3  , according to my ohmmeter,   but that grouping does not fly with  the  choice of  2 low voltage selections  , and THREE   high voltage  primary choices.   Puzzling to me.  Thank You for efforts in replying.   Dave W1DWZ

[W7TFO]

Commercial, not classic grade....

Known as "PA' in the older manufactures.

73DG

[wa3dsp]

Yes, that makes it more difficult. You would take some or all of winding A and add it to some or all of winding B. You just have to get the phasing right. I suspect you could get a lot more voltages out using the 220 taps on 120.

Hopefully there will be someone out there that either has it in their memory or has a datasheet. They probably used the same primary scheme in many of their transformers.

It is funny how they marketed this transformer. When it was first introduced there were no transistors then in their late catalogs they list it for transistor use.

[Tom WA3KLR]

Dave,

Some of the modern DVMs go wacko on inductive windings.  Try locking it on one range.  An old analog type of VOM is the sure bet.

You say that you believe the primary is split into two windings.  I assume you are seeing 4 isolated windings.  Then when running the 115 V tap you would also parallel connect the corresponding pins of the 230 volt winding.

The attached pdf is what I see the schematic should look like.

[Tom WA3KLR]

I have re-read your earlier posts and (yikes) this is my new schematic.

I think you should hook 120 vac across the full primary (high resistance winding) and use the multimeter on vac and look at the voltages on the secondary pins.  You will be getting 1/2 the proper vac out under this condition.

[W7TFO]

It has two identical tapped primaries; common and up the scale by 5 Volt increments from 105.

Parallel the input windings for low (115) Volts, series for (230) high.

Choose equal taps when operating in parallel.

It has two identical CENTER TAPPED secondary windings (that could be paralleled for more I).  The taps going out both ways provide 10, 11, or 14 V each. 

There area total of 14 terminals for the secondaries, 7 for each winding.

73DG

[W8ACR]

Here ya go - I think this is what you need.

[W7TFO]

A picture is worth a boatload of words, indeed!

73DG

[w1dwz]

Here ya go - I think this is what you need.

My  Prayers have been answered  ! !    God Bless  W8ACR  !    U made my day.    It is more  elaborate than I cud hv figured out with my pea brain .  I am grateful to u for taking the time to send that file along.         Best 73   Dave  W1DWZ

[w1dwz]

As a new subscriber  to AM FONE  Forum site,   I was elated to discover  that this  forum is loaded with talented ,  helpful  ,  cooperative ,  and  knowledgeable people who  are so willing to share all this good stuff.

So thanks to all who responded on my first listing .
73  de  Dave W1DWZ  Bristol RI

[W8ACR]

Aw shucks, 'tweren't nothin'. Just tryin' to pay it forward. Good luck!

Ron

[wa3dsp]

I knew someone would come through. That data sheet should be put somewhere public with the rest of the UTC data.