Operation
Functional Description
J1, J2, J3, and J4 controls are one-line hydraulic proportional with a solenoid valve that overrides the
hydraulic signal to hold the motor at maximum displacement. The control housing contains a solenoid
valve, a pressure compensating override (PCOR) valve, optional brake pressure defeat (BPD) valve, and
passages to route oil to the 4-way valve and to the servo piston ends. As signal pressure shifts the 4-way
valve, it ports pressures to the ends of the servo piston changing motor displacement. A threshold spring
and ramp spring(s) act on the opposite end of the 4-way. Variable signal pressure is fed to port X1.
Solenoid Valve
The solenoid valve (item M1) is a 2-position 3-way valve that passes the external signal pressure to the
end of the 4-way valve, or blocks the external signal and drains the end of the 4-way valve to the motor
case. The J1 and J3 solenoid coils are 12 volt. The J2 and J4 are 24 volt. The J1 and J2 solenoids have DIN
connectors. The J3 and J4 solenoids have Jet Jr. Timer connectors. The logic for the control is
•
If J3 or J4 are energized operation is proportional; if de-energized output is maximum displacement.
•
If J1 or J2 are energized output is maximum displacement; if de-energized operation is proportional.
J1, J2 Schematic Diagram
T2
T1
B
A
T7
max.
disp.
L2
M4
M3
M2
M5
T8
T3
L1
M1
P107 826
X1
Service Manual
Series 51 Hydraulic Proportional Controls Service Manual
J1, J2, J3, J4 Controls
32
11009446 • Rev BA • July 2014