The AM Forum

A friend has a HV transformer that's part of a homebrew power supply that he plans to give me. The owner indicates that the only identifying markings are the manufacturer, which was Western Electric, and the number CW-303058. There's also the familiar anchor stamped on it, which would indicate it was made for the USN. I've not been able to find any information on this from web searches. Does anyone have any suggestions on where I might find specs for it? Did WE publish catalogs?

73,
Jim

Jim,
     There was also another designation on the transformer  "STK. NO. N17-T-77095-1001"   Apparently a stock number, I would guess. Gentlemen, any help finding the specs on this transformer would be greatly appreciated.
---Marty, KK4RF---

Most all WE xfmrs start with a KS #  Your numbers are special stock numbers, no way to tell what the xfmr is.  Someone would have to know what piece of equipment it was made for and then look at the manual to find the specs.  Beyond that it's just a guessing game.  The xfmr, even though it has a WE logo, was probably made by some other maker.

Fred

Once you measure the voltage and get the ratio, you should be able to make a very good estimation of the current.  If the transformer is a standard open-frame unit, not in oil or encased in pitch, a rule of thumb that I have used for many years is somewhere between 10 and 15 watts per pound.  For oil filled transformers, the oil adds weight, but often the core is somewhat smaller... so you may need to make an adjustment. 

This is for standard E-I cores and not hypersil transformers, which can weigh up to 30% less and then some, depending on the exact transformer.

What is the physical makeup of the transformer?  Do you know anything about the voltage rating and/or how much it weighs?

what Steve said ..... ;D ;D ;D

Marty: thanx for posting the additional information.

Fred and Steve: thanx also for weighing in. I don't yet have the transformer in hand. It's a Marty's place about 8 hours drive from my QTH, so I won't have it for awhile. I'll do some tests on it after I get it. I was just trying to see if I could find any information in the interim. Again, thanx for the responses.

73,
Jim

Gentlemen,
     Thanks for the comments so far. I took a picture of the transformer. Hopefully the file is not too large for this site. I don't know how to reduce it in digital size. Anyway the picture shows the transformer and there is an identical one right behind it. The dimensions of the transformer are 6.25 inches Wide X  6.5 inches High   X   5.5 inches Deep. There is a mounting flange on the top and the bottom 7.75 inches by 5.5 inches. I have no clue what these transformers weigh as they are attached to the chassis. They were painted battle-ship grey and have the US Navy Anchor (it's upside down on this image.)
     I don't know if this is oil-filled or pitch-filled. I'm not familiar with those processes. Guys, any further help or comments are greatly appreciated. 73s for now---Marty, KK4RF

My guess, but possible around 300VA. 

Joe -GMS

It looks to be mounted in an existing power supply.  Can you determine what the voltage rating of the caps are? That might help. And if there is a choke, whats it's rating?

Xfmr looks like it could be one made by WE,  that type casing is a style they used.  Ratings could be labeled on the bottom surface.  I have WE plate xfmrs, some have the ratings on them, some don't.  Xfmr is most likely potted.

Seems that the two xfmrs may be connected together to increase the VA rating.  I agree with Joe, about 300 VA on the safe side, maybe a little more with ICAS.

Fred

If they were made by another Company by specs provided by WECo.. and were made in sufficient volume, a "KS" number would have been assigned. However, during the war effort and beyond, WECo. made a number of transformers in house based on specs provided by the requisitioner. Further, WECo. throughout its lifetime, made many transformers of many types, with its own in house coding and were never KS'ed.

Pete,  Good to know.  I was on a site today going through page after page of WE xfmrs and coils.  Noticed none of them had KS #, must be the in house coding.  I guess the KS numbers were used on xfmrs made by companies other than WE to WE specs.  I think all the ones I have here have KS numbers.

Fred

And if the transformer production was a limited run, for a specific non-Bell System job, it generally would never get into any catalog. Drawings would have been made for assembly, characteristics, specs, etc. but those drawings generally remained within the Bell System or WECO. file archives. Have no clue if any of that stuff was retained by anyone after the Bell System and WECo. disappeared.

Gentlemen,
     Thanks for all the help. I actually had picked up 3 homebrew supplies, 2 of which used 2 of these transformers in parallel to get more current.  The ham who built them, back in the 60's and early 70's, used oil-filled capacitors, and I saw a 3 KV rating listed on one of those. He used a voltage doubler rectifier circuit in these supplies and claims he was getting 2500 volts out of the supplies. I had hoped that the manufacturer specs on these would not be so difficult to find on the internet. I guess at some point I may apply some voltage to the primary to see what comes out the secondary. I probably ought to buy a variac someday.  I suspect these are about 1000 volt secondaries. He had used one of these supplies for a home-brew linear amp. Anyway, thanks again for all the help, Gentlemen. 73s,  Marty, KK4RF

Probably on track.  The label by the switch shows "2500 VDC."