[ Was "Replacement Motors for Electric Player Pianos"

What had started as a highly informative discussion, with safety
implications, has become a thread of disjointed anecdotal rebuttals
that dilute the value of the original topic.

Doug Bullock started the thread when he discussed a recent fire in
a collector's music room.  That fire was reported in a local Ohio
newspaper as well as TV web pages.  I, too, viewed those video reports.

 [ Ref. 121219 MMDigest, Duo-Art Piano Fire Destroys Instruments
 [ In Home, by D. L. Bullock

Based on my personal knowledge of fire hazards of reproducing piano
motors, I added a few comments in a follow up posting to Doug's.
Oddly, my comments which only discussed Duo-Art original equipment
motors, was posted by MMD under the title of "Replacement Motors for
Electric Player Pianos".  Being smitten with the spirit of the holiday
season, I did not protest the inaccuracy of topic assigned my posting.

Subscribers wishing to research Duo-Art electric motors in the future
will have to be somewhat clairvoyant and look under the topic,
"Replacement Motors for Electric Player Pianos" to find my comments
on Duo-Art motors.  Numerous other posts succeeded mine, also listed
under the same topic just mentioned, most dealing only with the Duo-Art
motor.

As far as I know, the Duo-Art piano motor is usually a Holtzer Cabot
motor.  The motor has a plate that lists it's required voltage and
current.  The plate further lists its RPM and gives the "frame" which
is usually ST-17, ST-18 or something like that.  It leaves nothing to
imagination or speculation.

Ampico motors are about the same, but sometimes the motor is
Westinghouse.  The _big_ difference is Ampico is clockwise rotation,
Duo-Art rotation is counter-clockwise.  Also, the mounting feet of
the Ampico motor are not present on Duo-Art motors.  Both have start
windings and centrifugal start switches.  Neither have overload
protection.  Both will catch fire or smolder if rotation is stalled
for a few minutes.

Previously when I said modern motors have thermal protection, that
comment went wildly into orbit.  Thermal protection is usually a
circuit breaker that detects high current, not frame temperature.
Modern motors having thermal protection may self reset when cool,
or require the user to push the reset button, which is usually red.

I regret that I may have caused confusion about thermal protection.
It is really overload protection, in most cases using bimetallic
thermal switches.

Anything that causes these Holtzer Cabot motors to stall will create a
fire hazard.  The Duo-Art mechanism can create the problem by selecting
Tempo zero when the expression system has closed the spill valve.  Any
situation that causes the roll to stop when high expression levels are
set will cause the Duo-Art motor to overload and possibly catch fire.
As Doug originally mentioned, bearing failure can cause rotation
cessation, and thus overload.

Owner awareness of this is the primary safety device.  If you don't
believe it, get your affairs in order, turn on the piano, and go to
bed.

Happy New Year!

Bob Taylor
Missouri

 [ MMD articles about fire, including fire in player pianos, are
 [ at http://www.mmdigest.com/Archives/KWIC/F/fire.html 
 [ MMDigest articles about the electric motors in mechanical
 [ music instruments will be found in the indices at
 [ http://www.mmdigest.com/Archives/KWIC/M/motor.html  and
 [ http://www.mmdigest.com/Archives/KWIC/M/motors.html  -- Robbie