I just had a thought of another possibility. I have always assumed that when my jacks stalled, that is exactly what happened... I have never checked into this, but I suppose that it could be the circuit breaker tripping as load increases and the amp draw goes up. They are automatic resetting breakers. My thought is that if oversized breakers were installed, that possibly the motor could make enough power to do some harm... But if this theory is correct, them it is a faulty installation, not the jacks fault
I will look into this when I get a chance. It may be awhile though as the TT is parked in a non testable position right now, and it is to hot here now to do anything that isn't necessary outside.