Some time ago, I got the 17" x 17" pump for Duo-Art, but I still need
an electric motor for it; the original motor was 110V DC, and burned.
According to the table in the Duo-Art reproducing piano service manual,
I will get the right rotation speed of the pump by using a motor with
1450 rpm and a pulley with the diametre of 1-3/4".

A company can sell me an one-phase 220 AC motor which runs at 1415 rpm
fully loaded, and up to 1500 rpm with no load.  The motor has a cooling
fan and aluminium case and looks really good.  In another place, it is
mentioned that the Duo-Art grand piano is driven by a 1/4 hp motor, and
the upright is driven by a 1/8 hp motor.  The actual motor available
is 120W ( 1/6 hp ).  Would it work out with a 120W motor?

One concern is that the replacement motor has ball bearings, in
opposition to old motors.  The workshop said that motors with no ball
bearings aren't sold anymore, so of course I have tried to find old
motors that could fit, but they all are burnt, shorted or difficult to
find.  I haven't the chance to test the motor in silent surroundings
before buying it,  but would electric motors with ball bearings
generally make objectionable rumble when driving a player piano?

There were also two kinds of the motor, with and without high starting
torque; the one with higher starting torque was more expensive, and
much larger.  Will I be fine with the motor with lower starting
torque?

What motors do satisfied Duo-Art owners use for their pianos?
(One-phase or three-phase, power, rpm?)

Thomas Henden, Norway

 [ Thomas, operate the new motor, with no load, at the shop before you
 [ buy it.  If it hums while in contact with the workbench, it will hum
 [ when it's installed in the piano.  Reducing the mains voltage to the
 [ motor might eliminate the hum, with a slight reduction in power.
 [
 [ A DC motor has no hum, when powered by pure DC !  Ask the motor shop
 [ if the old motor could be rebuilt for 200-220 vdc, and the cost of
 [ a simple ac-to-dc power converter.  -- Robbie