Manitowoc MLC150-1, Service Maintenance Manual

Page: 101 / 206

Manitowoc
Published 03-21-2021, Control # 264-01
5-3
MLC150-1 SERVICE/MAINTENANCE MANUAL HOISTS
5
center, the holding valve begins to close, slowing the load. At
center, the check valve is again closed, preventing motor
outflow and downward movement of the load. An orifice in
the unchecked circuit prevents abruptness in starting and
changes in hoist speed.
Pilot-Operated Relief Valve
The relief valve in the motor protects the motor from
excessive pressure, such as might occur when bringing a
heavy load to a quick stop when lowering.
Raising Load
When system flow is in the up direction, the holding valve
remains in the unchecked position and has no effect on
operation.
Motor displacement
Each motor contains an electronic displacement control. The
motor will stay at maximum displacement until the drum
begins to turn. The motor will shift towards minimum
displacement in proportion to the position of the control
handle. Each motor is also equipped with an electronic
pressure compensator that will shift the motor back towards
maximum displacement if pressure in the circuit rises above
a set pressure to ensure that the drum has sufficient torque
to reach full line pull in all conditions.
REFERENCE
ONLY