two-position switch (D) labeled PUMP CON-
TROL MODE is used to select either the AUTO
or MAN (manual) control mode. The next split-
legend indicator (E) labeled PUMP 1 and PUMP
2 illuminates to indicate which pump is assigned
the NORMAL position. Normal and standby
pump assignment is done by a switch on the LO
pump controller in the engine room.
If the LO pressure drops to 9 psig, or if both
electric pumps lose power, a third air-driven pump
provides oil to the MRG. This pump is called a
COAST DOWN PUMP. It has an indicator (F)
labeled PUMP RUNNING on the PCC to show
when it is running. The coastdown pump will only
run if the shaft is turning. Also, it will stop if the
LO pressure exceeds 15 psig. The next indicator
down (G) is labeled AIR PRESSURE LOW. It
illuminates and sounds an alarm to alert the
operator when the air supply to the coastdown
pump is low. It activates at 2700 psig.
The speed control push buttons are used for
manual speed control of the electric LO pumps.
They are labeled LOW SPEED (H), HIGH
SPEED (I), and STOP (J). They will illuminate
to indicate the status of the pump(s). The operator
may use these push buttons in the manual mode
to STOP, run in HIGH SPEED, or run in LOW
SPEED the normal or standby LO pumps. First,
the NORMAL PUMP is selected (its selection is
shown by the NORMAL PUMP ASSIGNMENT
PUMP 1/PUMP 2 indicator (E)). Then, the
operator manually starts the selected pump to start
the LO system. After the LO system is started,
the operator may put the system in automatic by
placing the PUMP CONTROL MODE switch (D)
to AUTO. In the AUTO mode, the pumps cycle
up in speed in response to pressure decreases. If
the pressure drops to 15 psig, the NORMAL
PUMP shifts from LOW SPEED to HIGH
SPEED. A drop in pressure to 13 psig causes the
STANDBY PUMP to start in LOW SPEED. A
further decrease in pressure to 11 psig causes the
standby pump to go to HIGH SPEED. When
system pressure returns, the pumps must be
Figure 6-9.--Gear lube oil panel.
manually cycled to lower speeds or off.
BEARING LOW PRESS illuminates and an
The next indicator (K) labeled SUMP LEVEL
alarm sounds. The operator can monitor the LO
LOW, alerts the operator when the level of the
pressure at the PCC by using the hydraulically
MRG oil sump drops below 870 gallons. The
most remote bearing pressure on the meter (C)
indicator (L) next to SUMP LEVEL LOW is the
labeled REMOTE BEARING PRESS.
STRAINER HIGH AP. If the differential pressure
Control is available from the PCC for the two
across the LO strainer exceeds 12 psid, this
motor-driven, two-speed pumps. The rotary
indicator illuminates and an alarm sounds.
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