Sorry for the delay. I have been busy.
There may be another explanation.
Faulty windings.
I had the same thing happen in a box fan motor conversion. It acted fine, until loaded. Meters said it was fine. But it just would not work right.
(that's probably why someone threw it away?
)
Faulty windings can do some
Really crazy stuff.
"Controller" with a mechanical device does not sound like a controller to me.
It sounds like a 'relay driver'.
"Clipping" with a mechanical device, connecting a load large enough to make much difference, sounds like shorting, or sounds like a bad idea.
Would maybe be OK with a BIG arse IGBT brick. 1600V 150A? But not driven with a relay driver.
Bruce,
Maybe one of should mention your yard art ECM weighs... uh... "less than" 10 pounds?
G-