Unforeseen problems with PowerRoll

Hi friends.  The PowerRoll seems to be a great device, and it works
wonderful, but here are a few cautions that should be observed with it.

Turbine pumps.

When subjected to long plays a turbine motor is prone to overheating.
The PowerRoll has a "jukebox" mode (extended play) -- if this is used,
the motor will overheat.

Turbine motors (suction boxes) are not designed for continuous opera-
tion.  These devices require air flow over the motor to keep it cool.
In a tight player, the air that enters the suction box comes from the
collapsing pneumatics in the pneumatic roll motor and the stack bleeds,
plus a small amount of transient valve losses.  The operation of the
automatic sustain pedal also contributes to the total amount of air
passing through the vacuum pump.

Although belt-driven pumps (commonly referred to as 'box pumps') are
somewhat better than turbine pumps against overheating,  extended plays
still put an undue strain on the old motor and associated parts.  As
Karl Ellison pointed out in MMD, the Ampico player at the AMICA
convention smelled "burned" after an hour of extended operation.

However, using PowerRoll in the new Story & Clark roll players will
require that the on-and-hold sensing finger be artificially activated,
thus allowing the vacuum pump to come on (and stay) on.  Also, since the
PowerRoll bar will cover the sense switch port that tells the unit
there is paper on the tracker bar, the electric roll motor will engage.
Further, it will stay on during the entire time the PowerRoll system
is being used.  This may cause uneven wear or overheating in the motor
bearings.  The last thing you want is the roll motor trying to turn when
using the PowerRoll.

Regards
Andy & Chris Taylor - "The Lone Arranger"
Tempola Music Rolls - "Taylor Made" Just For You
http://home.swbell.net/tempola/index.htm