Manitowoc Grove GRT880 Service Manual

5-1
GRT880 SERVICE MANUAL HOIST AND COUNTERWEIGHT
5
Published 10/19/2017, Control # 618-00
GROVE
SECTION 5
HOIST AND COUNTERWEIGHT
SECTION CONTENTS
Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-1
Theory of Operation . . . . . . . . . . . . . . . . . . . . . . . . 5-1
Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-2
Warm-up Procedure . . . . . . . . . . . . . . . . . . . . . . . 5-2
Hoist Area Access . . . . . . . . . . . . . . . . . . . . . . . . 5-2
Installing Cable On Hoist . . . . . . . . . . . . . . . . . . . . 5-3
Removing/Installing the Hoist . . . . . . . . . . . . . . . . 5-4
Removing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-4
Installing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-4
Functional Check . . . . . . . . . . . . . . . . . . . . . . . . . 5-4
Hoist Fluid Level Check . . . . . . . . . . . . . . . . . . . . 5-4
Usage and Inspection . . . . . . . . . . . . . . . . . . . . . . 5-6
Preventative Maintenance . . . . . . . . . . . . . . . . . . 5-6
Oil Sampling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-7
Brake Test Procedure . . . . . . . . . . . . . . . . . . . . . . 5-8
Motor, Motor Control Valve, And Brake . . . . . . . . 5-8
Description. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-8
Hoist Rotation and Minimum Wrap Indicator
System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-9
Description. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-9
Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-9
Hoist Control Valves . . . . . . . . . . . . . . . . . . . . . . . 5-10
Description. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-10
Removable Counterweight . . . . . . . . . . . . . . . . . 5-11
Counterweight Control Panel. . . . . . . . . . . . . . . . 5-11
Removing. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-12
Installing. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-12
DESCRIPTION
One standard hoist is available for both the main and
auxiliary, the MTW19-71-241 (Figure 5-4). The hoist
incorporates one dual displacement piston motor which
drives a reduction unit within the hoist. The hoist utilizes
planetary reduction with a multi-disc automatic brake that is
spring applied and hydraulically released. The hoist motor
controls both speed and torque of the hoist.
The hoist operates in two modes - High or Low Speed. In
High Speed the pilot solenoid valve shifts the selector spool
on the motor to provide minimum motor displacement. This
gives high line speed and low torque.
In Low Speed the pilot solenoid valve shifts the selector
spool on the motor to provide maximum motor displacement.
This gives low line speeds and high torque.
THEORY OF OPERATION
Flow from pump number one and two is routed through the
swivel to the directional control valve bank.
When the main hoist joystick in the cab is moved from
neutral, it sends an electrically controlled signal to the main
hoist directional control valve to shift the valve spool to route
hydraulic flow to the hoist motor or motor control valve.
When the auxiliary hoist joystick in the cab is moved from
neutral, it sends an electrically controlled signal to the
auxiliary hoist directional control valve to shift the valve spool
to route hydraulic flow to the hoist motor or motor control
valve.
Reference Only

Manitowoc Grove GRT880 Specifications

General

Brand	Manitowoc
Model	Grove GRT880
Category	Construction Equipment
Language	English