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Revision A4: Sep, 2010
Section III Sub-section 9
ELECTRICAL POWER
Pilot’s Operating Manual
In the event of reverse current, overvoltage, or over excitation faults being detected, the GCU will signal
the GLC to open, thereby removing the faulty system from the busbars and illuminating the relevant
GEN FAIL annunciator.
NOTE: An attempt to reinstate an off-line generator can be made using the GEN CLOSE-TRIP
switch.
SINGLE GENERATOR FAILURE (Figure 6)
A faulty generator may be tripped off-line automatically by its GCU, or by operation of the GEN CLOSE-
TRIP switch to the momentary TRIP position. With the unserviceable generator off-line, operating the
BUS TIE switch to CLOSE closes the BUS TIE contactor so that the serviceable generator feeds
busbars PS1 and PS2 as well as PE.
DOUBLE GENERATOR FAILURE (Figure 7)
Following a double generator failure, both generator contactors open. Both battery contactors also open
to prevent the batteries from powering the non-essential loads on PS1 and PS2 busbars.
The following annunciators will illuminate.
Selection of the BATT switch to EMERG connects direct supplies from the batteries to the emergency
contactors to make sure they remain energized closed. These supplies also make sure the battery
contactors are opened, should they have failed to do so due to a fault in the automatic circuits. To
achieve the maximum time on battery power, it is necessary that load-shedding is carried out.
Refer to the Pilot Checklist - EMERGENCY PROCEDURES - for DOUBLE GENERATOR FAILURE.
MWS panel
ELECT
CNTCTR
BATT 1
CNTCTR
BATT 2
FAIL
GEN 1
FAIL
GEN 2
BUS TIE
OPEN
Repeater annunciator flashes
XS 1
FAIL
XS 2
FAIL
INV 1
FAIL
INV 2
FAIL
STBY INV
ON
Overhead Roof Panel