4
HOW IT WORKS
(Refer to wiring diagrams)
Plus 48 (example voltage) volts are picked up from the primary (power) wire system for
operation of the control circuits at the rear terminal of the cut off contactor and run via the
fuse and white 20 ga. wire to the terminal strip where the white wire of the motor cable carries
the 48 volts through the plug/socket to the control cable and the terminal strip of the control
console and then to the input of the key switch (white wire).
Turn key on: Plus 48V are applied to the meter, the rotary switch (red)
and through the control cable red wire, cable plug and
socket and motor cable and terminal strip to PMC small
terminal (rear one) and to the cut off contactor which turns
on and applies plus 48V to the B+ term of the PMC. (To
determine plug & socket prong assignments--see page 7.)
Push lever
The rotary switch puts 48V to the forward contactor via
Forward: the control cable and motor cable green wire. The forward
contactor turns on and completes the primary power circuit
to the electric motor.
Push lever
The potentiometer raises the control resistance to the PMC
forward
sufficiently for the PMC to start turning the motor. This
slightly
operation uses the blue and brown wires of the control
more:
cable/motor cable.
Push lever
Motor speeds up because pot rotates further and the
forward
resistance to PMC (across the blue and brown wires)
more:
further increases.
Pull lever
The motor slows down because the pot decreases resistance
back:
to the PMC over the blue & brown wires. (The motor can be
stopped by the PMC before the forward contactor cuts off.)
Pull lever
Plus 48V is dropped from the green control wire, turning
back to past
off the forward contactor and breaking the output of the
the forward
PMC to the motor.
contactor
turn on point:
Pull lever
The rotary switch puts 48V on the orange wire, reverse
back
contactor is turned on, connecting the motor to
(reverse):
the PMC output with the fields reversed i.e. the current
flows in the opposite direction in the field coils.
