THE NEW PIPER AIRCRAFT, INC.
PA-32-301FT / 301XTC
MAINTENANCE MANUAL
PAGE 9
Jun 1/03
2G9
24-30-00
D. Alternator Removal
The alternator is factory-installed by the engine manufacturer (Lycoming) using Lycoming mounting
brackets. Removal and installation instructions may be found in the appropriate vendor service
publication or in the instructions / drawings for Lycoming Kit No. 05J22487.
E. Bench Tests
The only equipment required to bench check the alternator is an ohmmeter. Zero ohmmeter when
each resistance setting is selected. Zeroing is accomplished by touching ohmmeter probes together
and adjusting zero knob to align meter on full scale reading.
(1) Rectifier Ground and Positive Diode Test (Refer to Figure 6.)
CAUTION: DO NOT USE DIGITAL OHMMETER FOR THIS TEST; IT WILL GIVE FALSE
INDICATIONS.
(a) Set the ohmmeter selector switch to resistance scale 10 and zero the meter.
(b) Attach one ohmmeter lead to BAT terminal and the other to the STA (Stator) terminal. A
reading of 60 ohms should be obtained. Reverse leads. An infinite (no needle movement)
should be obtained.
(c) A reading of 60 ohms or less in both directions indicates:
1 A defective positive diode.
2 A grounded positive diode plate.
3
A grounded alternator BAT terminal.
(d) Infinite reading (no needle movement) in both directions indicates an open STA terminal
connection.
(2) Stator Ground and Negative Diode Test (Refer to Figure 7.)
CA
UTION: DO NOT USE DIGITAL OHMMETER FOR THIS TEST; IT WILL GIVE FALSE
INDICATIONS.
(a) Set the ohmmeter selector switch on resistance scale 10 and zero meter.
(b) Connect one lead to the “STA’’ terminal and the other lead to the GRD terminal. A reading
of approximately 60 ohms should be obtained. Reverse leads and check in opposite
direction. An infinite reading (no needle movement) should be obtained.
(c) A reading of 60 ohms or less in both directions indicates:
1 A defective negative diode.
2 A grounded positive diode plate.
3 A grounded alternator BAT terminal.
4 A grounded STA terminal.
5
A grounded stator winding (laminations grounded or windings grounded to front or
rear housing).
(d) Infinite readings (no needle movement) in both directions indicates an open STA terminal
connection.
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