Identify High Current Power Supply Transformer

Hi Gang,

I have a large and heavy power supply transformer that is part of a high current power supply project that was featured in 73 magazine back in 1973. It was started by a ham radio operator and was never finished. I am going to finish it, if I can. I am trying to identify the transformer leads. This is for a 12 volt, 40 to 60 amp output. Here are the markings:

This transformer was made by ADC and is marked 541-010 REV H. There is a marking on it that says 3-19470 and what I think is a date code of 7438. There are terminal connections on one side that are numbered 1 - 6. On the other side the connections are numbered 7 - 14. I need to know the connection scheme for this transformer so I can put it to use. I contacted who I thought was the manufacturer "ADC" for information, and that did not help.

I don't have the issue of 73 magazine, and I don't even know if this is the same transformer that may have been part of the construction article. I can take pictures and post them if that might help.

Anybody have any ideas?

Thanks a lot.

Mike

The first thing you do is make a table of all of the resistances between the various connections to determine where each winding is. All of the resistances will be quite low some less than an ohm. The primary will probably be two windings maybe with taps so that it can be series'd or paralleled with taps to adjust for various line voltages. On a transformer like that it is likely to be useable on line voltages from 90 Volts to 260 Volts depending on how the windings and taps are connected.

Once you think you have found the primary, the highest resistance winding(s), connect it to a variac or variable transformer. My guess is that terminal one connects to terminal four and terminal three connects to terminal six and the line connects between terminals one and three, but that is just a guess for 120 VAC. It doesn't matter what the power rating is because you are not going to draw much current for testing purposes. The purpose of the variac is to keep from blowing breakers if you have the connections wrong. Advance the variac and while monitoring the primary current with a clamp on ammeter if you have one, otherwise listen carefully if it sounds like it is drawing high current with excessive hum or even blowing a breaker or a fuse. If that happens, you obviously have the wrong primary connections. When operating properly, the variac should get to the line voltage without excessive current draw, noise or hum or popping breakers.

With line voltage now on the transformer, measure the secondary terminals with an AC voltmeter and map out all of the measurements. I suspect that there are four secondary windings that can be series'd or paralleled for a number of different voltages. Bob