Solenoid Valve; Vent Valve; Time Delay Module; Pump Cutoff Pressure Switch - Komatsu 730E Operation & Maintenance Manual

Maintenance - Section 42
Page 42-4

Solenoid Valve

Solenoid valve (19), when energized, allows oil to
flow to the hydraulic motor.

Vent Valve

With vent valve (1, Figure 42-3) closed, the pump
continues to operate until maximum grease pressure
is achieved. As this occurs, the vent valve opens and
allows the grease pressure to drop to zero, so the
injectors can recharge for their next output cycle.
24VDC Lubrication Cycle Timer
Lubrication cycle timer (2, Figure 42-11) provides a
24VDC timed-interval signal to operate solenoid
valve (19, Figure 42-3), causing the grease pump
motor to operate. This timer is mounted in the cab
interface compartment.

Time Delay Module

Time delay module (7, Figure 42-6), located in the
electrical interface cabinet, provides a one minute
delay in the low pressure warning light circuit to allow
a normally operating system to attain full grease sys-
tem pressure without activating the warning light. If
the system fails to reach 13 790 kPa (2,000 psi)
within this period of time, the timer will apply 24VDC
to several relays, which will illuminate the low pres-
sure warning light in the overhead panel. An external
604K ohm resistor determines the delay period.

Pump Cutoff Pressure Switch

Pump cutoff pressure switch (21, Figure 42-3) is a
normally open switch set at 20 685 kPa (3,000 psi).
This switch de-energizes the pump solenoid relay
when the grease line pressure reaches the switch
pressure setting, turning off the motor and pump.
Automatic Lubrication System

Unloader Valve

Unloader valve (20) is mounted on a tee fitting with
pump cutoff pressure switch (21). This valve will
relieve grease pressure in the pump if pressure
exceeds 27 580 kPa (4,000 psi). This valve has been
factory adjusted and is not repairable.

Pressure Switch

Pressure switch (15, Figure 42-4) is a normally open
switch set at 13 790 kPa (2,000 psi). This switch
monitors grease pressure in the injector bank on the
rear axle housing. If the appropriate grease pressure
is not achieved during the normal pump cycle, the
warning system will be activated, turning on warning
light to notify operator a problem exists in the lubrica-
tion system.

Pressure Gauge

Pressure gauge (18, Figure 42-3) monitors hydraulic
oil pressure to the inlet of the hydraulic motor.

Manual Override Button

Manual override button (17, Figure 42-3) is used to
actuate the hydraulic motor to manually activate a
lubrication cycle.

Injectors

Injectors deliver a controlled amount of pressurized
lubricant to a designated lubrication point. Refer to
Figure 42-3 and 42-4 for the locations of each lubri-
cated component.
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