Back drive over speed is prevented by an electrical interlock. This interlock consists of a
relay (Item 250, Diagram 12) which allows automatic shut off of the back drive motor
approximately 10 minutes after the main drive motor is shut off. The time needed before
back drive shut off is necessary since low friction in the pillow block bearing and the
mass of the rotating assembly allow ten (10) to twenty (20) minutes of rotation after main
drive motor shut off.
1.5 Bowl and Conveyor Speed
The 414 C ENTRIFUGE Bowl is operated between 1900 and 3200 rpm’s depending on the
application. The conveyor rotates at approximately 10 to 79 rpm’s less than the bowl in the same
direction. The 414 CENTRIFUGE operates at all times with the bowl and conveyor turning in
the same direction and the conveyor turning slower than the bowl. The main drive motor should
be wired so that the bowl always turns clockwise when viewed from the feed tube end.
The small sunwheel in the gearbox is used to vary the differential speed between the bowl and
conveyor. If the sunwheel is “fixed,” that is, not rotated by the back drive motor, the differential
will equal the bowl RPM divided by the gearbox ratio (57:1). If it turns in the same direction as
the bowl, the differential will be less than when it is fixed. If it turns in the opposite direction as
the bowl, the differential will be greater than when it’s fixed. (See Diagram 10)
1.6 Step sheaves having two pitch diameter sizes each on the main drive motor and bowl sheaves
permit operation of the 414 CENTRIFUGE at 1900, 2500 and 3200 rpm’s. The bowl speed is
determined by the combination of sheave sizes selected on the bowl and motor. The motor
mount is made to allow the motor and sheave to move a full sheave width for proper alignment
to obtain the full range of bowl speeds.
Caution:
DO NOT ATTEMPT TO OPERATE 414 CENTRIFUGE AT BOWL SPEEDS ABOVE 3200 RPM’S.
SPEEDS ABOVE 3200 RPM’S WILL EXCEED THE DESIGN SAFETY LIMITS. THIS COULD
CAUSE THE MACHINE TO DESTROY ITSELF POSSIBLY CAUSING INJURY OR DEATH.
9
To Next Page
Loading...