Starting Motor Control Circuit; Starting Motor Service Test Specifications - Piper PA-31-350 Maintenance Manual

T-1020
MAINTENANCE MANUAL
CARBON PILE
KNIFE SWITCH
AMMETER
VOLTMETER
GROUND
Figure 80-6. Stall - Torque Hook-Up
2. If no difficulty is indicated in the above test, a stall torque test may be made to see if the starting motor
is producing its rated cranking power. Make test connections as shown in Figure 80-6.
3. If torque and current are not within specifications, check the seating of the brushes and internal
connections for high resistance. If these checks are made and found to be in good order, replace frame
and field assembly and retest starter.
STARTING MOTOR CONTROL CIRCUIT.
1. Inspect the control circuit wiring between the battery, solenoid and manual starting switches for
breaks, poor connections and faulty insulation. Tighten all connections and make sure solenoid is
firmly mounted and makes a good ground connection.
2. Check the voltage loss across the switch contacts during normal starting. If loss is in excess of 0.2
volts per 100 amperes, the solenoid should be replaced.
3. If solenoid fails to operate when the manual switch is turned on or if it fails to release when the manual
switch is released, it should be removed and tested to specifications. If either opening or closing
voltages are not specified, replace the solenoid.
STARTING MOTOR SERVICE TEST SPECIFICATIONS.
Prestolite specifications for 24 volt starting motors installed as standard equipment on the T-1020 are as
follows:
80-10-15
4118
Page 80-06
Issued: September 2,1981
PIPER AIRCRAFT