transformer wire color code

[N8DLJ]

I have a xformer pulled from a old 13.8 regulated supply. I pulled it apart several years ago and all that remains of the schematic I drew for the primary hook up is the tape that once held the paper to the xformer. The transformer is mfg. by American Monarch Corp., Minneapolis,MN. the AM part # is 501462, customer part # is 25D84516-G01. Primary wiring consists of a pair of black, a pair of red, a pair of blue and a blue with white stripe. Blue may be violet, I am color blind. The red pair went to a non polarized capacitor. The blue went to diodes into the cathode side, anode grounded. Must have been a negative regulated supply.

I'm running off of memory, looking for some definate answers before I hook it up and let the smoke fly. Thanks and 73

[KC8VWM]

Common transformer wiring color codes can be found listed in the ARRL manuals.

Otherwise, I hope this standardized RMA transformer color code chart indicated at this link helps...

http://www.radioremembered.org/xfmr.htm

[K9YLI]

the pair of red going to a non poplarized cap.. about 600mfd and AC indicates this may be
a resonant transformer set up.. IBM used extensivly in the early 70s.
It amounts to an ac regulated power suppy..
If you don't connect the AC cap then the outputs of the whole thing are lower. by a volt or 2..
Short out the red leads and no output anywhere. remove the short and all pops back to normal..

I have A SYSTEM 3 MOD 8 memory supply.. 8.5 volts at about 60 amps..

[K9STH]

Although there definitely were "standards" of wire colors for transformers, a LOT of transformer manufacturers didn't seem to follow these. I have a number of transformers that the colors definitely do not follow any standard. Therefore, I took the time to "ohm out" the various windings and then to actually measure the voltage from each winding. Finally, attached labels to each wire with the measured voltage thereon. That way, when I go to use the transformer in a project, I can directly connect the proper wires without having to go back and determine which is which.

Glen, K9STH

[N8DLJ]

Thanks for the suggestions so far. Unfortunatly this xformer does not seem to follow the standards. K9YLI unclouds things a little, I've had experience with a resonant xformer I pulled from a 48v battery charger to build a 48v regulated supply. It also used a "motor start capacitor".

A local operator is working on a Social Unsecurity budget. Lost the xformer in his regulated supply, was just trying to get something in there for him. You know how it is when one of your rag chew friends is down.

[WA7KKP]

Sounds like you got a transformer that is ferro-resonant -- that's how they 'regulated' the voltage. You apply 120v AC to the black/black wires, a resonating capacitor to the red/red wires (you'll have to do some research for the right value). The blue wires and the one with the white stripe are the LV secondary. Polarity of the power supply is determined by how the diodes are hooked up.

You can check the RMS ac voltage across the blue wires with 120 applied to the primary. You'll need in the vicinity of 36-40v AC to use this as a 12/13.8v DC power supply. If you want to use it, you'll need the resonanting cap for sure.

If American Monarch Corp. is still in business, they can tell you what it was used for . . .

Gary WA7KKP