Piper SARATOGA PA-32-301 Maintenance Manual page 192

PIPER AIRCRAFT
PA-32-301/301T
MAINTENANCE MANUAL
A. Disconnect the regulator plug and install a jumper from the positive terminal of battery to pin 2
(F pin of regulator plug).
-CA UTION -
Operate engine not more than 2 minutes with jumper installed,
damage to components of electrical system could occur.
B. Start engine - turn on alternator switch - apply electrical load - (turn on landing light). Slowly
increase engine speed to determine that voltage of step 2 increases. Stop RPM increase when voltage measures
.0 volt.
C. Voltage reading at battery should increase above previous reading 0.5 volts or more.
D. Turn off landing light - turn off alternator switch - shut down engine.
If the increase in voltage reading is still below 0.5 volt, the problem is in wiring harness or alternator.
E. Remove the jumper end from the voltage regulator plug and connect it to the "FLD" pin of the
alternator (plug removed). This eliminates the wiring harness to prove the alternator.
F. Leave alternator regulator plug disconnected.
G. Start engine - turn on alternator switch - apply electrical load - (turn on taxi and landing lights).
Slowly increase engine speed to determine that voltage of step 2 increases. Stop RPM increase when voltage
measures .0 volts. Observe 2 minute operation caution.
If the voltage increase is now above 0.5 volt, fault is wiring harness. Repair or remove and replace harness.
If the voltage increase is still below 0.5 volt, the fault is in alternator and should be removed from the
aircraft for bench test.
ALTERNATOR BENCH TEST PROCEDURES.
When on-aircraft-testing determines an alternator malfunction. The following bench tests should be
performed on the removed alternator.
An ohmmeter is the only equipment required for bench check. Ohmmeter should be "zeroed" when each
resistance setting is selected. "Zeroing" is accomplished by touching the ohmmeter probes together and
adjusting zero knob to align meter on full scale reading.
RECTIFIER GROUND AND POSITIVE DIODE TEST.
- CA UTION -
DO NOT use digital ohmmeter for this test, because it willgivefalse
indications.
1. Set the ohmmeter selector switch to resistance scale 10 and zero the meter.
2. Attach one ohmmeter lead to "BAT' terminal and the other to the "STA" terminal. Check for a
reading of 60 ohms, it should be obtained in one direction and an infinite (no needle movement) in other
direction (reverse leads to check opposite direction).
3. A reading of 60 ohms or less in both directions indicates:
A. A defective positive diode.
B. A grounded positive diode plate.
C. A grounded alternator "BAT' terminal.
4. Infinite reading (no needle movement) in both directions indicates an open "STA" (Stator) terminal
connection.
EFFECTIVITY: FORD
24-32-10
Page 24-27
Added: August 23, 1982
1H24