Piper Navajo PA-31 Service Manual page 699

PIPER NAVAJO SERVICE MANUAL
11-3. TROUBLESHOOTING. Troubles
peculiar to the electrical
system are
listed in Table XI-I along with their probable causes and suggested remedies.
The wiring diagrams
included in the manual will give a physical breakdown of
the different electrical
circuits used in the airplane.
Refer to Electrical Dia-
grams in rear of this section.
After the trouble has been corrected,
check entire electrical system for
security and operation of its components.
11-4.
ALTERNATOR SYSTEMS.
11-5.
DESCRIPTION OF ALTERNATOR SYSTEMS. For each alternator,
the
alternator output circuit is connected by means of a 90-ampere circuit breaker,
a filter in the line to eliminate radio interference and a shunt to monitor alter-
nator output.
The field circuit consists of a 10-ampere thermal circuit breaker,
a volt-
age regulator, selector switch, overvoltage relay, radio noise filter and a special
switch ganged to the 90-ampere circuit breaker to remove field voltage from the
alternator
should the circuit breaker open.
The field and output circuits of both alternators
are joined by a bus bar
which directs current
to the battery.
A shunt is installed between the battery
and bus to measure current flow to and from the battery.
The field circuit is
combined with the master switch to turn off the alternator when the master switch
is turned off.
A second set of components is installed in the field circuit should a failure
of the main regulating system occur.
The 90-ampere alternator
circuit breakers should not be switched on and
off under load for testing or any other reason.
Reissued: 10/12/79
ELECTRICAL SYSTEM
4A21