Alternator System Checking; Alternator Adjustments - Piper PA-24 Comanche Service Manual

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PIPER
COMANCHE SERVICE MANl'Al
f. The
drive
end head supports a sealed.
prelubricated
ball bearing in which the drive end of the rotor
shaft rotates.
9·6Ic. Checking Alternator System. The ammeter is equipped to check the electrical output-input of the
battery. Should the alternator sho.... no output on the ammeter. check the alternator output and field thermo
circuit protector s. and ammeter line fuses. If a further check of the ammeter shows no output from the
a
uernaror.
check the a
lremator
system. (Refer to Figure
9~27b.)
a. Ascertain that the ammeter is operating properly.
b. Disconnect the battery lead
(+)
at the alternator.
c.
Disconnect the field leads (F! and F2) at the alternator.
d. Ascertain that all electrical units are off and the battery is fully charged.
e. Turn on the master switch.
f.
To check the alternator output circuit. connect a voltmeter or
12
volt test light to the battery lead
a
nd
to ground. If a reading of approximately
12
volts registers on the voltmeter or the test light lights. the
battery circuit is operational. Should there be no indication of voltage. trace back through the output circuit
until voltage is indicated. (Refer to Figure 9·27b.) A component that allows no voltage to pass through it
should be replaced.
g. To check the field circuit. connect a voltmeter or
12
volt test light to each field lead and
to
ground.
and separately check as follows:
I. A check of the F I circuit will give a variable voltage. if any voltage is indicated on the voltmeter
or if any filament glow is indicated on the test light. the circuit is operational.
., The check of the F2 circuit should give a reading of approximately
12
volts or the test lamp
should glow normally for an operational circuit.
.l.
Both the main and
auxiliarv
field circuits
mav
be checked in a like manner.
4.
I
I'
indication shows a
possible
malfunction of the voltage regulator and before installing a
new
regulator. refer
to
Paragraph 9-6 I m. For the overvoltage control. refer to Paragraph 9-61 s.
h. If voltage is indicated at both the battery lead and field lead. the alternator should be checked for
pos...ible malfunction. refer
to
Paragraph 9-61 i.
9~n
Id. Adjustments. The only adjustments necessary to maintain the alternator system is the adjustment of
the voltage control on the voltage regulator. A voltage of
14.2 volts
is maintained. All other control adjust-
ments are made at time of installation and need not be reset.
IMPORTA~T
Since the alternator and regulator are designed for use on only one
polarity system. the following precautions must be observed when
working on the charging unit. Failure to observe these precautions
will result in serious damage to the electrical equipment.
a.
When installing a battery. always make absolutely sure the ground polarity of the battery and the
ground polarity of the alternator are the same.
b. When connecting a booster
battery,
make certain to connect the negative
battery
terminals together
and the positive battery terminals together.
c. When connecting a charger to the battery. connect the charger positive lead to the battery positive
terminal and the charger negative lead to the battery negative terminal.
d.
'e\er operate the alternator on open circuit. Make absolutely certain all connections in the circuit
are secure.
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)SSt'ED: 8/18/72
3B21
ELECTRICAL S\'STEM