Grant Erwin wrote...

The bearings in the pony motor must be bad, eh? Friction causes heat ..

As indicated in my first post, that was my second thought, after a
possible shorted pony contactor. But the bearings do pass the "spin
freely and sound good" test. Moreover, the end caps and motor shaft were
cooler than the body of the motor, and given the laws of thermodynamics,
I think it's safe to conclude that the heat isn't coming from the
bearings.

In retrospect, I think I noticed the heat after a long series of start
and stop cycles. (I had been tweaking the balancing caps.) And it's a
heck of a job for that 1-horse motor to spin up the idler -- it doesn't
have much starting torque. In fact, it needs a rope pull to get the ball
rolling. After that, spin-up takes around three seconds.

Maybe it was simply built-up heat in the laminations that the fan didn't
have time to dissipate because of the short run times. I'm hoping to give
it a good long test on Monday, and resolve the question for certain.
Today, we're working on the new shop. It's going up fast, but still takes
priority while my beer-priced friends are over (G).

Cheers!

Jim