Old Transformer Replacement

We need to find a replacement transformer for an old unit. The original has a dead short between primary and secondary. As best as I can tell, the transformer is marked Vernon Co., V_6021, Pri:135VAC Sec:

25VAC. It feeds into a full wave rectifier into a DC motor, no capacitors. The motor draws 24V at 12.2A, per the mfg dataplate. Any ideas for a replacement transformer? Line frequency is 400Hz, but 60Hz transformer will be just fine.

Thanks, Steve

Reply to
sck0006
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Two of part # 7846 TR from MPJA in parallel. It's a 24V 10A transformer, at $17.95 each.

Ed

Reply to
ehsjr

Grab the xfmr out of a an old junk microwave, 500w or better should serve. Cut-out/remove high voltage winding and knock out the "current shunts (core material "shims" wedged in the windings windows.)

Rewind with wire capable of handling the current you wish, with the proper number of turns to deliver the voltage you desire (this can easily be determined by winding any number of test turns (10 or more to get some accuracy), measure voltage and divide by number of turns to give you a volts/per-turn ratio.

Cost (if xfmr is gotten from a dump) $0.00 USD! :-)

Regards, JS

Reply to
John Smith

Thanks guys, I appreciate the help.

Steve

Reply to
Steve

No problem. However, if I might inquire, did you go the hard route of building your own, or find a place to buy one?

Warm regards, JS

Reply to
John Smith

We will probably buy one. This is meant for relatively long periods of use, and in my experience rewound mot's run hot and usually need fan cooling. We will probably just order two of the xfmr's the previous poster recommended, that is, if the cust decides it's worth it to them.

Thanks again, Steve

Reply to
Steve

I understand.

Was just hoping good old "American Ingenuity" had come into play. :-)

Regards, JS

Reply to
John Smith

I've actually rewound microwave transformers before, they're quite handy. I use one for a high voltage power supply using the schematic Sam has at

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It works beautifully, and I have the top of the core of the transformer sticking out of the case for cooling. I would definitely consider using a mot if it weren't customer equipment, I'm not sure how long they use it at a time, and I don't want it to melt down on them for whatever reason.

Thanks, Steve

Reply to
sck0006

Bad idea John,

1) Microwave transformers are sealed with Epoxy making impossible to unwind.

2) Even if you can unwind, you are still facing with dangerous chance, there are many turns, to unwind without know the actual number of turns would destroy the motor (through wrong voltage/power).

Never do that, and Never recommend to any one.

Regards,

Jack.

Reply to
Jakthehammer

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make a great variety of transformers for any applications. Will wind special cases. Have a great museum of old radios...been in business since the 1920s or so...

John :-#)#

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Reply to
John Robertson

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