The initial post on this subject only stated that the motor seemed
too hot.  The conditions were that the piano had been playing for
three hours.

I doubt that the motor was overheating.  After three hours, Ampico
and Duo-Art motors get very warm or even hot.  The Duo-Art tends to
get hotter, since the motor is under more load at all times in that
system.  It should be pointed out that neither motor has a cooling
fan and that air movement in the piano is very limited.  Under these
conditions, a motor should get hot.

The term "hot" is relative.  After many hours of operation, the hot
motor should not burn your skin; but at the same time, holding the
palm of your hand on the motor for more than five seconds will be
uncomfortable.

Bob Taylor