Yes, i have just hacked (literally) another MOT.
Anyway, I am using it for an electronics power supply.
Since the Magnetizing current (no load) was about 12 Amps I decided to add some copper. 40 turns later the current is down to 2.75A which is ok.
The secondaries use 18 AWG for a 25.4 VAC CT output and 12 AWG for a 13.4VAC output.
The core area of 64mm x 35mm works out to about a 375VA unit.
My question is:
If I expect to draw a max load of 8A from the 25.4 VAC secondary = 203VA, does this mean that I can draw 375-203 = 172 VA or 12.8A from the 13.4VAC secondary?
Also, at full draw 375 VA/120VAC = 3.125 A in the primary. Does this add on to the no load magnetizing current of 2.75A?
I think 2.75A is too much for the magnetizing current. Sounds like you are still saturating the core somewhat. I believe it should be below 1A for a proper design.
Microwaves usually use a resonant voltage doubler, hence the shunts to increase the impedance, running it without wil cause the offload current to go up.
You'll be able to make a supply from it, but if you want something that can be run for hours you'll have to do some carefull redesign.