Voltage ratio on this output transformer isn't making sense

[cooldude666]

Ive got a P-P output transformer from a traynor vvm-1 im trying to use in a build. I just put a few volts on one of its secondaries and read from the primaries but the results aren't making sense! My meter is showing 12.05 AC into what was the 2ohm secondary, but only 11.38 ac on the primaries!! Is this tranny dead somehow? It worked fine before i ripped the yvm apart. Is my technique wrong?

Im running a 3 prong from my variac, using the ground prong's lead for my dvm's black clip, and have an alligator connecting hot to the secondary, and then my dvm connected to both primaries. Ive a second dvm on the hot wire of the cord to read voltage in.

I have to assume I'm doing something stupid.

[Jazz P Bass]

Try ditching the ground connection from the Variac.
That is not what you want to measure anyway.

[cooldude666]

Well what DO i want to measure?? I assumed ground would be my reference point. I guess since the transforrmer isnt grounded that thats incorrect? Should i use the ground secondary as reference for the primary? Help me obi-wan kenobi

[52 Bill]

Well what DO i want to measure?? I assumed ground would be my reference point.

Your description has me confused, I assume that your variac has a 3-prong ac outlet for the variable voltage output. Is this correct? And you have one wire from the OT secondary connected to what would be the hot ac line and the other end of the OT secondary is connected to ground? or to the ac neutral wire?

And how are you connecting the meter to the OT primary winding?

Remember that unless it specifically says so, most variacs are not isolated from the ac line input. So use caution when clip leading anything to it.

Oh yeah, I like to use 1 volt or 10 volts as the input voltage because the math is a lot easier.

[cooldude666]

I figured it out. 30.7:1 is my ratio. And yeah, but ive got a calculator so the math is pretty easy