Manitowoc MLC100-1 Service And Maintenance Manual

Manitowoc Published 10-09-2020, Control # 259-06 10-3
MLC80A-1/MLC90A-1/MLC100A-1/MLC100-1 SERVICE/MAINTENANCE MANUAL ACCESSORIES
10
CRAWLER POSITIONING CYLINDERS
OPERATION
Crawler Positioning Cylinders Overview
The crawler positioning cylinders are controlled by a switch
on the right side cab console.
The system consists of the main pump A, a 2-position,
proportional solenoid-operated accessory enable valve, a 3-
position, solenoid-operated control valve, and two double-
acting hydraulic cylinders. The crawlers are locked in the
extended or retracted position by manually inserted pins.
The crawler positioning switch on the cab console
communicates with the gantry cylinder solenoid valves via
the CCS.
The crawler positioning switch is a 3-position momentary
switch that is spring returned to the off position when
released. The switch is active whenever the engine is
running.
Neutral
When there is no command from crawler positioning switch,
the following occurs:
• The solenoid on the accessory enable valve is
deenergized and a spring shifts the valve to block pump
A flow to the high pressure accessory valve bank.
• The solenoids on the crawler positioning control valve
are deenergized and springs shift the valve to the
neutral position.
• The crawler positioning cylinders remain in their last
position.
Retract
When a retract command is sent by the crawler positioning
switch, the following occurs:
• The proportional solenoid on the accessory enable valve
is energized by a PWM signal from the control system to
adjust the flow rate of oil to the high pressure accessory
valve bank.
• At the same time, the retract solenoid on the crawler
positioning control valve is energized by 24 V
DC
from
the CCS.
• The energized solenoid shifts the valve spool to the
position that routes hydraulic oil to the rod end of the
crawler positioning cylinders and the cylinders retract.
• The hydraulic oil in the barrel end of the cylinders flows
back to tank via the high pressure accessory valve.
Extend
When an extend command is sent by the crawler positioning
switch, the following occurs:
• The proportional solenoid on the accessory enable valve
is energized by a PWM signal from the control system to
adjust the flow rate of oil to the high pressure accessory
valve bank.
• At the same time, the extend solenoid on the crawler
positioning control valve is energized by 24 V
DC
from
the CCS.
• The energized solenoid shifts the valve spool to the
position that routes hydraulic oil to the barrel end of the
crawler positioning cylinders and the cylinders extend.
• The hydraulic oil in the rod end of the cylinders flows
back to tank via the high pressure accessory valve.
HYDRAULIC COOLING FAN OPERATION
See Figure 10-1 and Figure 10-2
The system consists of the fan pump, the hydraulic oil cooler
and motor, and the hydraulic oil temperature switch.
The hydraulic cooling fan is controlled by the temperature of
the hydraulic oil:
• It turns on when the hydraulic oil temperature rises
above 60°C (140°F)
• It turns off when the hydraulic oil temperature drops
below 58°C (136.4°F).
The fan motor is equipped with a check valve that prevents
cavitation when the motor is stopped by allowing return oil to
flow from the motor outlet to motor inlet until the motor
comes to a complete stop.
FOR REFERENCE
ONLY

Manitowoc MLC100-1 Specifications

General

Brand	Manitowoc
Model	MLC100-1
Category	Construction Equipment
Language	English