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Re: Duplamat 300w transformer replacement

>I realize this is a long shot, but my Dupla 300w transformer died this
>weekend. I have been scouring the net and my local electronics places
>looking for a replacement. After reading all the FAQs on DIY cable heat, it
>seemed that I should be able to make my own replacement, but I can't find a
>24v 12.5A transformer anywhere.

Most of the usual commericals units top out at 5, 8, or 10 amps. Getting
above 10 amps usually means surplus, and even then you'll be looking for an
unusually large unit. You could probably find one from Galco Industrial
Electronics/Supply (can't remember which), possibly from a company called
Magnetek or maybe Hammond Manufacturing. Thats for new of course, and
expensive, so read on...

>The Dupla transformer says:
>Primary 115V 50-60Hz, 2.9A
>Secondary 24V Max, 12.5A

Try Fair Radio Sales of Lima, OH (http://www.fairradio.com). I believe they
have a 26v 8 amp transformer that would work IF TWO ARE WIRED IN
*PARALLEL*. The 2v difference would make (for example) a 200w cable run at
about 235 watts, which shouldn't pose a problem for the cable. Send them
some email though -- they might have something that will work perfectly for

BTW, a 12.5 amp transformer can run a 300 watt cable, so if you have just a
200 watter you could get by with a smaller 9-10 amp transformer.
watts/volts = amps (or at least close, the equation is for DC).

The best bet for safety is to fuse the primary (high voltage) side of the
transformer in the hot (black lead, or smooth lead, that connects to the
smaller prong of a polarized plug). Fusing both leads is a good idea if you
are really worried about shorts. Use a GFCI on the transformer and a ground
probe in your tank and there is very little chance of a problem getting by