Piper SARATOGA PA-32-301 Maintenance Manual page 211

PIPER AIRCRAFT
PA-32-301/301T
MAINTENANCE MANUAL
2. Check the alternator according to the manufacturer's instructions, to determine if it is functioning
properly. This test must be done with the regulator out of the circuit. After completing this test, reconnect the
regulator into the circuit.
3. Use a good quality accurate voltmeter with at least a 15 volt scale.
4. Connect the positive voltmeter lead to the red wire at the regulator harness connector, or terminal
block. Connect the negative voltmeter lead to the regulator housing. (Note) Do not connect the voltmeter
across the battery, because the regulator is designed to compensate for resistance contained within the wiring
harness.
5. With the alternator turning at sufficient rpm to produce a half load condition, or approximately 25
amperes output, the voltmeter should read between 13.6 and 14.3 volts. The ambient temperatures
surrounding the voltage regulator should be between 50°F to 100°F while this test is being made.
6. 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. 14, be connected between the regulator
case and the alternator. If the regulator does not regulate between 13.6 and 14.4 volts, one of the following
conditions may exist:
A. Regulates, but out of specification. The regulator is out of calibration and must be replaced.
-NOTE
-
The 68804-3 (Lamar) regulator has a black ground wire that must
have a low resistance connection to the ground system. It is
adjustable and should be set to 14.0 volts.
B. The voltmeter continues to read battery voltage.
(I) Poor or open connections within the wiring harness.
(2) The regulator is "open."
C. Voltage continues to rise.
(I) Regulator housing not grounded.
(2) Regulator shorted, must be replaced.
7. These are some of the things to look for in case of failure:
A. Poor or loose connections.
B. Poor ground on the regulator housing.
C. Shorted alternator windings.
D. A grounded yellow wire. (This will cause instantaneous failure.)
E. Disconnecting the regulator while the circuit energized.
F. Open circuit operation of the alternator. (The battery disconnected.)
-NOTE -
Proper installation of solderless terminals on aluminum cables
presents special difficulty in that each individual strand is insulated
by an oxide coating. This oxide coating must be broken down in the
crimping process and some method employed to prevent its
reforming (usually a corrosion preventative jell material). For this
reason Piper does Not recommend the repair or replacement of
loose, corroded or other unsatisfactory conditions of solderless
terminals on aluminum cables. When an unsatisfactory condition is
discovered, Piper recommends that the complete cable assembly be
replaced. Should this not be practical, it is permissible to replace the
aluminum cable assembly with a copper cable assembly, using a
copper cable two sizes smaller. Example: AL-1 aluminum cable
replaced with AN-3 copper cable.
24-34-01
Page 24-46
Revised: August 23, 1982
1119