TABLE XI-VI. TROUBLESHOOTING CHART (ELECTRICAL SYSTEM)
Trouble
Cause
Remedy
ALTERNATOR
Zero output indicated
Open field circuit.
With master switch turned on check
on ammeter regardless of
for battery voltage (I2V) from ship's
RPM(refer to alternator
main bus through entire field circuit to
system test procedure).
alternator field terminal. Measure
voltage from ground(-) to the
following points (+) in sequence: -
bus bar, field circuit breaker (5A),
field terminals of master switch,
voltage regulator and alternator field
terminal.
Interruption of voltage through any of
these points isolates the faulty
component or wire which must be
replaced.
Open output circuit.
With master switch turned on check
for battery voltage ( 12V) from ship's
main bus through entire output circuit
Measure voltage from ground (-) to the
following points (+) in sequence: bus
bar and ammeter,
Zero output indicated
Open output circuit.
Interruption of voltagethrough any of
on ammeter regardless
thesepoints isolates thefaulty
of RPM (refer to alternator
component or wire which must be
system test procedure)
replaced
Open field winding in
Disconnect field of alternator terminal
alternator.
from field wiring and check for
continuity from field terminal to ground
with ohmmeter (20-100 ohms)
depending on brush contact resistance.
(Pull propeller slowly by hand turning
alternator rotor through 360° of travel.)
If resistance is high check brushes for
spring tension and excessive wear and
replace if necessary. If brushes are okay
and field reads open, replace alternator.
—CAUTION—
Turn magneto switch to off before turning prop.
PIPER AIRCRAFT
PA-28-161 CADET
AIRPLANE MAINTENANCE MANUAL
Issued: FEBRUARY. 28, 1989
ELECTRICAL SYSTEM
2E6
