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10 - 6
Operation (cont’d)
Pilot Relief Valve
Pilot pressure is controlled by the pilot relief valve setting.
Pressure can be varied using adjuster
56-6
which holds
poppet
56-2
against seat
56-3
by means of spring
56-5
. If
the pressure exceeds the set value, the poppet lifts to vent
excess
Pp
pressure to tank.
Solenoid Proportional Pressure Control (SPPC) Valve
The function of the SPPC valve is to provide a means of
varying the horsepower settings of the two pumps according
to the operating mode selected. Each mode selection
causes an electrical signal
F
to be applied to the valve
solenoid. The signal current level is dependent on the mode
selected. The solenoid converts the electrical signal into a
thrust from plunger
E
.
When solenoid
58
is energised, the thrust of plunger
E
moves spool
103
to the left to connect input port
B
(at pilot
pump
Pp
pressure) to output port
C
. The output pressure at
port
C
is routed to chamber
A
where it acts as a back
pressure to oppose the thrust of plunger
E
. High back
pressure causes spool
103
to move so that output port
C
connects to drain port
D
lowering the output pressure and
hence the back pressure. The result is a level output
(horsepower signal) pressure which is proportional to
solenoid plunger thrust and determined by the proportion of
input pressure (at port
B
) connected to port
C
via spool
103
.
Section E
Hydraulics
9803/6410
Section E
10 - 6
Issue 1
Hydraulic Pump/Regulator
Summary of Contents for JS130
Page 65: ...Section 3 Section 3 9803 6410 Issue 1 9 1 9 1 Routine Maintenance Component Location Diagram...
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Page 119: ...3 1 Section C Electrics 9803 6410 Section C 3 1 Issue 1 Layout Operator s Cab...
Page 142: ...5 3 Section C Electrics 9803 6410 Section C 5 3 Issue 1 Pump Control FLOW CHART...
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Page 210: ...3 4 Section E Hydraulics 9803 6410 Section E 3 4 Issue 2 Schematics Shuttle Block...
Page 532: ...Contents Page No Technical Data 1 1 i Engine 9803 6410 i Issue 1 Section K Section K...