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Reference
Only
Manitowoc
Published 09-09-16, Control # 229-09
5-33
MLC650 SERVICE/MAINTENANCE MANUAL
HOISTS
5
55
DRUM 5 BOOM HOIST (VPC-MAX)
Drum 5 Brake Overview
A brake is attached to the drum motors, with the brake discs
attached to the drum shaft. The brakes are controlled by
joystick movement and the drum park brake switch.The
brakes are applied by spring force and released by hydraulic
pressure.
The brakes must be fully released to allow the drum to rotate
for hoisting and lowering operations. To accomplish this, the
brake pressure must be above 10,5 bar (153 psi). Any
pressure below this could cause the brakes to remain
partially applied, which could damage the drum brake
system.
If brake hydraulic pressure or electrical control is lost, the
brake is applied by spring force.
Hydraulic flow to the drum 5 brake release solenoid valve is
provided by the main and charge pressure hydraulic flow
from pump 6.
Drum 5 Brake Operation
.
The J2 joystick sends a 24 V
DC
output to the drum 5 park
switch. The drum park switch is closed in the UN-PARK
position, causing the switch to send a 24 V
DC
signal back to
the J2 joystick. The J2 joystick communicates the un-park
brake command to the CCMC11 control module via the
controller area network bus (CAN Bus).
When the CCMC11 control module receives the un-park
command from the J2 joystick, the CCMC11 control module
sends a 24 V
DC
output to the drum brake release solenoid
valve, energizing the solenoid. The brake release solenoid
valve shifts position, routing hydraulic fluid from the pump 6
to the drum brake piston, releasing the brake.
When the drum brake switch is moved to the ON-PARK
position, the drum park switch is open, sending a 0 V
DC
signal back to the J2 joystick. The J2 joystick communicates
the on-park brake command to the CCMC11 control module
via the CAN Bus.
When the CCMC11 control module receives the on-park
command from the J2 joystick, the CCMC11 control module
sends a 0 V
DC
output voltage to the drum brake solenoid
valve, de-energizing the solenoid. This causes the brake
release valve to return to the default position, allowing the
fluid in the brake piston to flow through the brake release
solenoid valve, and back to the tank. The reduced hydraulic
pressure allows spring force to apply the drum brake.
Drum 5 Hoisting Operation
.
To enable the control system to drive the drum 5 pump and
motor, the switches listed below must be in the stated
positions:
•
Seat safety switch closed
•
Drum 5 park switch in the OFF position
When the drum 5 joystick is moved in the hoist up direction, a
signal is sent to the IOLC33 control module via the controller
area network bus (CAN Bus) to ramp up the pulse-width
modulation (PWM) duty cycle to the A-side solenoid of the
pump 6 electronic displacement control (EDC). The PWM
signal is in proportion to the speed commanded by the
joystick. Increasing the PWM duty cycle increases the pump
swashplate angle, which increases the hydraulic flow from
the A-side of the pump. From the pump, the flow is routed to
the B-side of the drum motor.
A signal is sent to the IOLC30 control module via the CAN
Bus to ramp up the PWM duty cycle to the drum 5 motor
controller. Increasing the PWM duty cycle decreases the
swashplate angle in the motor, which increases the motor
speed until the rotational speed is maximized based on the
pump flow.
The drum 5 motor speed sensor and pump 6 pressure
transducer (drum 5 psi) provide closed loop feedback to the
control units. The control algorithm uses this feedback to
adjust the pump and motor flows while ramping up to, and
maintaining, the speeds commanded by the joystick.
CAUTION
Possible Machine Damage!
When raising or lowering a load, do not use the drum park
switch to stop the load movement, since this could cause
damage to the boom. Use the joystick for a controlled
smooth stop.
Summary of Contents for MLC650
Page 1: ...R e f e r e n c e O n l y Service Maintenance Manual Manitowoc MLC650 ...
Page 2: ...R e f e r e n c e O n l y ...
Page 4: ...R e f e r e n c e O n l y THE ORIGINAL LANGUAGE OF THIS PUBLICATION IS ENGLISH ...
Page 375: ...R e f e r e n c e O n l y ...
Page 376: ...R e f e r e n c e O n l y ...