PIPER CHEROKEE
SIX SERVICE
MANUAL
f. The voltage regulator heat sink, or case, is the ground connection for the electronic
circuit. Therefore, if this unit is tested on the bench, it is most important that a wire, No. 8
or larger, be connected between the regulator case and the alternator. If the regulator does
not regulate between 13.6 and 14.6 volts, one of the following conditions may exist:
1. Regulates,
but out of specification. The regulator
is out of calibration and must
be replaced.
2. The voltmeter continues to read battery voltage.
(a) Poor or open connections
within the wiring
harness.
(b) The regulator is "open."
3.
Voltage continues
to rise.
(a) Regulator
housing
not grounded.
(b) Regulator shorted, must be replaced.
g.
These are some of the things
to look for in case of
failure:
1. Poor or loose connections.
2. Poor ground on the regulator housing.
3. Shorted alternator windings.
4. A grounded yellow wire (This will cause instantaneous failure.)
5. Disconnecting the regulator while the circuit energized.
6. Open circuit operation of the alternator (The battery disconnected.)
10-30. OVER VOLTAGE RELAY.
10-31. CHECKING
OVER VOLTAGE RELAY.
The relay may be tested with the use
of a
good quality, accurate voltmeter, with a scale of at least 20-volts and a suitable power
supply, with an output
of at least 20-volts, or sufficient
batteries with a voltage divider to
regulate voltage. The test equipment may be connected by the following procedure:
a. B+ is connected to "Bat" of the over-voltage control.
b. B- is connected to the frame of the over-voltage control.
c. Be sure both connections are secure, and connected to a clean, bright surface.
d. Connect the positive lead of the voltmeter to the "Bat" terminal of the over-voltage
control.
e. Connect the negative lead of the voltmeter to the frame of the over-voltage control.
f. The over-voltage control is set to operate between 16.2 volts and 17.5 volts. By
adjusting the voltage, an audible "click" may be heard when the relay operates.
g. If the over-voltage
control does not operate between
16.2 and 17.5 volts, it must be
replaced.
ELECTRICAL
SYSTEM
Revised:
8/14/73
3C2
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