INTRODUCTION 2250 SERVICE/MAINTENANCE MANUAL
1-100
Published 11-06-15, Control # 040-13
The crane PC controls raising speed by varying the voltage
to both pump EDC’s and motor PCP’s in relation to handle
movement. As handle is moved back (RAISE), the crane PC
sends a signal to increase the pump swashplate angle. The
crane PC also sends a signal to motor servo to reduce the
motor displacement. The crane PC is continuously balancing
the system pressure and the motor displacement angle so
the motor displacement goes to minimum when handle is all
the way back, if torque requirement on the motors is not too
high.
Knowing the displacement of the motors, the crane PC may
then control the speed that the motors turn by regulating the
flow through the pumps.
When left control handle is moved to neutral position, the
crane PC sends an output signal to crawler travel pump
EDC’s to decrease swashplate angle, reducing oil flow
output. This shifts the motor servo back to maximum
displacement for slower output speed to slow the drum
rotation. The crane PC stores the load holding pressure in
pressure memory. After control handle neutral switch opens,
the PC sends an output signal to disable brake solenoid HS-
56 to apply brake before crawler travel pumps de-stroke.
LEFT HANDLE CONTROL
LEFT TRAVEL
SENDER
RIGHT TRAVEL
SENDER
LOWERRAISE
REGULATED 10V DC OUT
8
5A
OFF
3A
8T
88MC
RM19
DRUM 9
FLANGE
ENCODER
80N
A
B
A
B
DRUM 9 LEFT
MOTOR CONTROL
DRUM 9 RIGHT
MOTOR CONTROL
84A
83A
RIGHT TRAVEL
PUMP CONTROL
LEFT TRAVEL
PUMP CONTROL
A
B
B
A
LEFT CONTROL
ROTATION INDICATOR
88D
TRAVEL/DRUM 9
DIVERTING VALVE
AS
DRUM 9
BRAKE
PAWL IN
PAWL OUT
88C
88CA
88E
88N
83DS
8K
84DS
87FA
80P
5DA
5A
8
CAB POWER
OFF
ON
D
B
A
F
8P1
0
8
K1
50 AMP
0
10A
5D
5A
88MB
DRUM 9
MINIMUM
BAIL LIMIT
88MA
ENGINE
RUN/STOP
89GA
EDC
PCP
PCP
EDC
HS
54
HS
56
AS
22
21
DRUM 9
DRUM 9
K1
CRANE
PROGRAMMABLE
CONTROLLER
FIGURE 1-64
90QM
MAST
ACCUMULATOR
SENDER
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