Type 4013 counter torque hoist controller is recommended
for applications such as bucket hoists, boom hoists and magnet cranes,
where a fixed minimum load exists which insures an overhauling condition at
all times and where accurate positioning and slow steady speeds are not
The Counter Torque system uses reverse power to control
speed in the lowering direction without the need for a load brake.
Control in the hoisting direction is the standard
secondary resistor method with frequency responsive type acceleration.
In the lowering direction, the master switch is no effective until the
third point. If the load is heavy enough, it will begin to lower.
If the load is not heavy enough, it will try to hoist, but a frequency
sensing relay will prevent hoisting. The operator does not have to
reset the control by returning the master switch to the off point.
Moving the master switch to the fifth-point lower will accelerate the motor
to full speed under control of the frequency responsive accelerating relays
and drive the load down in regeneration. The operation in
fourth-point lowering is the same as described for the third point, except
the load accelerates to a faster speed.