Manitowoc 2250 Service Maintenance Manual

Reference Only
INTRODUCTION 2250 SERVICE/MAINTENANCE MANUAL
1-34
Published 07-19-16, Control # 249-01
When a control handle is moved, an input voltage in the
handle command direction is sent to the PC. The PC does
not release the selected brake until the load pressure
memory is reached to hold the load, as determined by the
system pressure sender.
When the hydraulic brake solenoid is enabled, the selected
brake valve shifts to block the tank port and supplies pilot
pressure from the boom/luffing jib charge pump to release
the selected brake.
When a brake solenoid is disabled, the solenoid valve closes
to block the charge pump port and to vent the brake pressure
to the tank, and the spring brake applies. If brake pressure or
electrical power is lost when operating, the brakes apply.
Load Drum Air Brakes
See Figure 1-19 for the following.
Each load drum brake has two air cylinders, and each
cylinder has two chambers. The first brake cylinder chamber
is a spring-applied/air-released brake controlled by the PC.
The other chamber is a working brake for free fall that is air-
applied/spring-released. The second brake cylinder
chamber is a spring-applied/air-released brake controlled by
the PC, and the other chamber is not used.
Release the load drum brakes by placing the selected load
drum brake switch in the OFF position. The PC enables the
brake solenoid when the load pressure memory is reached.
When the PC enables drum 1, 2, or 3 load drum brake
solenoid (AS-7, AS-9, or AS-11), regulated air shifts the
brake relay. This allows manifold air to close the quick-
release valves. Air flows to the brake cylinder chambers,
compressing the springs to release the brake. With the
selected load drum brake released, the load drum motor can
hold the load when operating in full-power operation.
In Standard mode, when either a selected load drum control
handle or a selected load drum brake switch is in the OFF
position, the brakes are spring-applied. Air in the brake
cylinders is exhausted to ensure that the load drum brake
spring applies. Exhausted air from the cylinders goes
through the quick-release valves when the sealing pressure
is exhausted off the valve diaphragms, opening the exhaust
ports. This occurs when pilot pressure is removed from the
brake relay valve.
0
0
K1
F10
8
8D
Limit Bypass
WB-25
87FA 87F
Maximum Angle Limit
Max. Working Angle Limit
Block-Up Limit WB-06
WB-17
WA-35
Limit Switch
Equalizer
Limit Switch
Boom Stop
8M
WD-13
Upper
Main
Lower
Main
Regulated 10V Out
RF-11
5A
System Fault Alarm
WC-34
WC-35
Operating Limit Alarm
Light
5A
WB-10
Seat Switch
WB-22
Left Rear Drum
Minimum Bail Limit Drum 1
WB-03
WB-14
Boom Up Limit
Maximum Bail Limit Drum 1
WB-02
Minimum Bail Limit Drum 2
WB-08
Maximum Bail Limit Drum 2
WB-07
Light
Luffing Jib Limit Bypass
WE-14
Engine Oil Pressure
WD-08
Engine Coolant Temp.
WD-09
3
8D
Minimum Bail Limit Drum 3
WB-04
Maximum Bail Limit Drum 3
WB-05
F7
WA-17
WA-18
Hydraulic Fluid Temp.
Hydraulic Fluid Level
Minimum Angle Limit
WB-16
3A
10A
Controller
Programmable
FIGURE 1-18

Manitowoc 2250 Specifications

General

Brand	Manitowoc
Model	2250
Category	Construction Equipment
Language	English