jcb JS130, Service Manual

Page: 125 / 533

3 - 7
Section C Electrics
9803/6410
Section C
3 - 7
Issue 1
Layout
Control, Function, Operation
Pump control depends on work such
as, H mode, large working load, S
mode, good fuel economy, and L
mode, for fine operation.
The supply current to
electromagnetic proportional
pressure reducing valve
which is built into the pump,
is regulated.
When L/F mode is selected
the boom lowering stroke of
control valve spool is
restricted.
Pump control
CONTROL
FUNCTION
OPERATION
3
It also decreases boom lowering
speed in L/F mode.
When starting, a momentary
negative control signal is
generated.
Prevents shock loads when starting
to lower the boom.
Pressure raised by 2-stage
MRV being operated by
solenoid valve.
Power increased when more force is
desired, or during travel.
Boom lowering speed
regulation
Cushioned Boom Starting
Pressure raising system
Selects travel motor 2-speed
positions, to give function of
restricting max. flow of pump.
High, middle or low speed travel
operation obtained by switch.
Performance improved during
F mode.
3-speed travel and max. flow
cut
After the key switch is turned
OFF there is a 5 seconds
delay before the battery relay
is cut OFF.
A power supply is maintained to
allow electrical devices to be
operated after key switch is turned
to OFF .
Power cut delay
Modulates movement of
control valve boom/arm
spools when they are
deselected.
When cushion control is selected
shock is relieved when boom and
arm are de-selected. When hard
operation is selected, the cushion is
turned off.
Cushion control
Pressure is maintained by a
pressure reducing valve,
dependent upon brake
selection.
Key OFF or lock SW ON: 100%
swing brake. Key ON and operation
other than swing: 50% swing brake.
Swing operation: 0% (release).
Swing brake/swing lock
With left console raised the
controls are isolated.
Unless the controls are immobilised,
by raising the left console, entering
and leaving the cab is impossible.
In an emergency, it is possible to
shut off the services immediately by
raising the console.
Lever lock (Left console)
An overcurrent sensing circuit is
fitted within the controller. When
the output is shorted, the power
transistor output is stopped,
thus preventing an internal
overload in the computer.
If power transistor output of
controller is shorted, the controller is
protected.
Overload protection
Radiator water temperature
Hydraulic oil temperature
Fuel remaining
Warning display
Monitor display
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