Hi:  Wurlitzer Pianinos that have the original small cast iron
open gear standard _and_ a 25-to-1 gear ratio require a higher speed
motor.  Original motors run about 1800 RPM and were manufactured by
Holtzer-Cabot.  There are other combinations of gear ratios and motor
speeds found in Wurlitzer instruments.

Many coin pianos use slow speed electric motors ranging from 1120
to 1150 RPM, and a blanket statement can't be made for any specific
manufacturer.  Depending on the individual instrument, I have seen
original motors with their original pulley system with motors as slow
as 800 RPM in a large Seeburg orchestrion with Holtzer-Cabot motor,
to an original 1750 RPM Emerson motor complete with original Electrova
data plate.

With too slow a motor speed there isn't enough vacuum, but when it's
too fast the installation becomes noisy, along with the additional wear
and tear issues to all the associated parts.

Dana Johnson