Creation: 01.31 - 2014
2-4-14
GPU - 406
GPU - 409
Generator Protective Circuit
PROBLEM
CAUSE
REMEDY
1. The output contactor opens
during power delivery, and the
GCM displays
“FAULT LATCHED,
FREQUENCY HIGH”.
A. A faulty connection exists
between the voltage sensing wire
on the contactor terminal and the
GCM.
A. Correct the wiring.
B. The engine speed is set too
high.
B. Decrease the engine speed
setting within the GCM.
C. The engine ECM is faulty.
C. Contact the engine
manufacturer. Replace the ECM if
necessary.
E. The GCM is faulty.
E. Replace the GCM.
2. The output contactor opens
during power delivery, and the
GCM displays
“FAULT LATCHED,
FREQUENCY LOW”.
A. A faulty connection exists
between the voltage sensing wire
on the contactor terminal and the
GCM.
A. Correct the wiring.
B. The engine speed is set too
low.
B. Increase the engine speed
setting within the GCM.
C. The engine ECM is faulty.
C. Contact the engine
manufacturer. Replace the ECM if
necessary.
D. The engine is overloaded.
D. Reduce the load at the aircraft.
E. The GCM is faulty.
E. Replace the GCM.
3. The output contactor opens
during power delivery, and the
GCM displays
“FAULT LATCHED,
VOLTS HIGH”.
A. A faulty connection exists
between the voltage sensing wire
on the contactor terminal and the
GCM.
A. Correct the wiring.
B. The GCM is faulty.
B. Replace the GCM.
4. The output contactor opens
during power delivery, and the
GCM displays
“FAULT LATCHED,
VOLTS LOW”.
A. A faulty connection exists
between the voltage sensing wire
on the contactor terminal and the
GCM.
A. Correct the wiring.
B. A faulty connection exists
between the generator exciter and
the GCM.
B. Correct the wiring.
C. The GCM is faulty.
C. Replace the GCM.
Property of American Airlines
Summary of Contents for GPU-406
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