isolation transformer toroid Mod

[mike1855]

Toroid as tested is:
core: Approximately 5.5 cm tall, 11 cm across, 6.5 cm
center hole, was best measurements I could get trying to
account for wire and insulation.

Toroid windings being used:
16 awg primary winding
16 awg secondary winding

Powered Toroid with variac set
at 120 volts out showed .01 amp current draw with no load. I thought this was kind of low.

Once powered up the Toroid out put is at 125 volts with no load then
drops to 120 @ .87amp current draw loaded with 100 watt light bulb.

I tested Volts per turn ratio and it is at 3 turns per
volts @ 120 volts input at primary.

Ok with that said, from the above testing results would this make a good isolation 120volt -120 volt transformer, good for around 3.5 amps?

It was originally a 1 kva 208-440 to 215 volt auto transformer that i removed the insulation from and separated the other sets of wires and narrowed down these two sets for my needs as an isolation transformer.

My concern is , will the windings be ok with 120 volts, or are they in reality still 220 volt windings? And if they are still 220 volt windings what problems would I notice running this on 120 volts

Also, are there any Toroid transformer calculators on line, ive searched and have not found what i was looking for.
Thanks

[SeanB]

Insulation is good enough for 440VAC, so will work at 120VAC. Best though is to do a high voltage insulation test between the 2 windings, typically 1000VDC for 30 seconds, and the insulation resistance must be over about 20Mohm with no arcing. Pass that and it is fine.

[mike1855]

if it passes that test would this be good enough for powering the average oscilloscope? Also any ideas where i can find a toroid power transformer calculator program? thanks