Dc Generation - Piper Cheyenne IIIA Airplane Maintenance Manual

PIPER AIRCRAFT
PA-42-720 (Advanced Trainer)
MAINTENANCE MANUAL
A. DC Generation (continued)
2. Fault Isolation
After the malfunctioning system or component has been repaired or adjusted, it is recommended
that the entire system be inspected for security and operation of its components. The wiring
diagram manual provides electrical schematics to be used along with conventional troubleshooting
methods.
CHART 1
FAULT ISOLATION (STARTER - GENERATOR)
Cause
(Sheet 1 of 3)
Remedy
Fault
Unit fails to operate or does
not attain normal speed.
Low voltage power source.
Check the power source to
make certain that full voltage
is being applied to the starter
terminals.
Defective switch in power
supply
Defective starter solenoid.
Damaged armature.
Short circuited or open
stator windings.
Improperly seated
brushes.
Eccentric commutator.
Replace switch.
Replace solenoid.
Replace the armature
assembly.
Replace the stator and
housing assembly.
Check brush seats and
increase brush run-in time.
Refinish commutator.
Excessive sparking at
brushes.
Short circuited or grounded
field windings.
Replace stator and housing
assembly.
Excessive clearance in
bearings or rough
bearing races.
Eccentric commutator.
Short circuit in armature
windings.
Brushes incorrectly
installed with top
bevel reversed.
Armature out of balance.
Insufficient brush run-in;
improper seating.
Replace bearings.
Refinish commutator.
Replace armature assembly.
Reverse and reset
Balance or replace
armature.
Run in brushes until
seated.
EFFECTIVITY:
040-999
PAGE 2 24-30-00
Jan
10/90
24-30-00