Piper Navajo PA-31 Service Manual page 719

g. Should there be no indication of voltage, trace back through the output cir-
cuit until voltage is indicated. (Refer to Figure 11-17.) A component that allows
no voltage
to pass through it should be replaced.
h.
Check each field circuit by the following procedure:
1. On lead connected
to (F1) terminal, connect a voltmeter to the field
lead and to ground. If voltmeter indicates any voltage the circuit is operational.
2. On lead connected to(F2) terminal, connect a voltmeter or 24-volt test
light to field lead and to ground. If a reading of approximately 24-volts registers
on the voltmeter or the test light lights, the circuit is operational.
3. Both the main and auxiliary field systems may be checked in a like
manner.
i . If voltage is indicated at both the battery lead and field lead, the alternator
should be checked for possible malfunction. (Refer to Paragraph 11-29.)
11-28. ADJUSTMENTS. The only adjustment necessary to maintain the alter-
nator system is the adjustment of the voltage control on the voltage regulator.
A voltage of 28.5 volts is maintained. All other control adjustments are made
at time of installation and need not be reset.
IMPORTANT
Since the alternator and regulator are designed for
use on only one polarity system, the following pre-
cautions must be observedwhen working on the charg-
ing circuit. Failure to observe these precautions will
result in serious damage to the electrical equipment.
a.
When installing a battery, always make abso-
lutely sure the ground polarity of the battery
and the ground polarity of the alternator are
the same.
b. When connecting a booster battery, make cer-
tain to connect the negative battery terminals
together and the positive battery terminals
together.
c. When connecting acharger to the battery, con-
nect the charger positive lead to the battery
positive terminal and the charger negative lead
to the battery negative terminal.
d. Never operate the alternator on open circuit.
Make absolutely certain all connections in the
circuit are secure.
PIPER NAVAJO SERVICE MANUAL
Reissued: 10/12/79
ELECTRICAL SYSTEM
Effectivity
PRESTOLITE
4B17