34
REVERSING DIRECTION OF DRUM ROTATION
In order to change the direction of rotation and brake operation, 2 components must be changed on the hoist. First, the motor
must be made to rotate in the opposite direction.
Th
is is done by exchanging positions of the brake valve and manifold block on
the motor. Secondly, the brake clutch assembly must be made e
ff
ective for the opposite direction of rotation.
Th
is is done by
reversing the inner race of the brake clutch assembly.
Figures “A” and “B” above show typical PD12C motor installations. Note that the only di
ff
erence between the two drawings is
the motor is rotated 180° (the “belly” of the motor moves to the opposite side). If the motor sha
ft
rotates clockwise in
fi
gure ‘A”
when the hoisting port is pressurized, it will rotate counterclockwise in
fi
gure “B”.
Motor
Case Drain
Brake Release
Circuit
Brake Release
Circuit
Hoisting
Port
Motor
Case Drain
Motor
Brake
Valve
M
Lowering
Port
DRN
DRN
BR
BR
Hoisting
Port
Lowering
Port
Motor
Brake
Valve
M
M = Manifold Block
³$´
³%´
1. Remove the four capscrews securing the brake valve to the
motor. Remove the four capscrews securing the manifold
block to the motor. Disconnect the motor case drain hose
at the motor.
NOTE:
Some installations have the
brake release hose connected directly to the motor,
instead of to the manifold block. In this case, dis-
connect the brake release hose at the motor port.
Stand hoist up on drum support with the motor end
up and secure in this position.
2. Before removing the motor, it is a good idea to note or
mark the position of the motor in relation to the hoist,
since it will be rotated 180° when reinstalled. Remove the
capscrews securing the motor to the hoist and carefully
remove the motor.
3. Remove the brake clutch assembly from the motor sup-
port.
4. Remove the snap ring and sprag bushing retainer from
one end only of the brake clutch assembly.
5. Pull the inner race out. Examine the race for scoring,
wear or indentations caused by the sprag cams. If the in-
ner race is not completely smooth, the assembly should be
replaced.
