Isolation transformer using 2 torrids

[fleetwise]

I came across a couple 4" diameter torrid transformers rated at 200va a while back. They were used in a marine low voltage lighting system and drop 120volts to 12 volts. If I were to hook them 12 volt to 12volt would I lose too much in the conversion to power a oscilloscope at 40 or 50 watts?

[budm]

Re: Isolation transformer using 2 torrids

Yes, you will have conversion lost but nothing to lose by trying to see if it will provide enough power, just use 40 Watts lamp for testing.

[fleetwise]

Re: Isolation transformer using 2 torrids

It works better than I thought it would. At 122 volts drawing .52 amps in, it has a 3.5 volt drop with a 60 watt bulb attached. So with a 118.5 volt output at .5 amps I'm happy. A .02 amp loss isn't a deal breaker.

[kaboom]

Re: Isolation transformer using 2 torrids

It works better than I thought it would. At 122 volts drawing .52 amps in, it has a 3.5 volt drop with a 60 watt bulb attached. So with a 118.5 volt output at .5 amps I'm happy. A .02 amp loss isn't a deal breaker.

You're loosing voltage, not current, when you backfeed one tx w/ the other one. That extra .02A on the line side only goes to losses in the two txs.

Measure the voltage one the 120 side of the second tx, before and after you hook the bulb up. Then use Ohm's law to calculate the impedance of your set up.

It sounds like you want to 'float' a scope. You'd be better off floating the equipment under test, as the entire scope and all "ground" leads will now float up to whatever you've got connected to it.

[fleetwise]

Re: Isolation transformer using 2 torrids

That was what I was originally wondering when I did this was the loss. At no load it showed 121 volts on the output(1 volt drop).
Thanks, I was wondering what it was going to happen with the ground.

To be usable for anything very large I would probably have to rewind the secondaries and parallel them instead