Starter Generator Service Test Specifications - Piper Cheyenne IIIA Airplane Maintenance Manual

PIPER AIRCRAFT
PA-42-720 (Advanced Trainer)
MAINTENANCE MANUAL
A. DC Generation (continued)
6. Adjustments of Starter Generator (continued)
(f) A starter generator with reversed polarity in the output voltage may be corrected by flashing the
field as in the procedure below:
CAUTION: DO NOT FLASH THE FIELD WHILE STARTER GENERATOR IS IN
OPERATION.
(1.) Disconnect the leads to the proper generator control unit.
(2.) Connect the negative terminal of a small battery (1.5 to 6 volts), or an equivalent dc power
supply, to terminal E of affected starter generator.
(3.) Connect a jumper wire from positive terminal of same battery to terminal A of same starter
generator.
NOTE: If flashing the field fails to correct generator polarity, check for incorrect
connections or defective field circuit.
7. Starter Generator Service Test Specifications
Lear Siegler leading particulars for the 28-volt starter generators installed as standard equipment
are as follows:
CHART 2
STARTER GENERATOR TEST SPECIFICATIONS
Rating (Minimum Continuous)
175 amperes, 28 volts at ground idle speed of 6,720 rpm.
300 amperes, 28 volts at 6,950 rpm.
300 amperes, 30.0 volts to maximum rated speed of 12,000 rpm.
External Starting Power Limitations:
1,700 amperes maximum, self-limiting with 30 volts maximum at start receptacle and 0.004
ohm aircraft circuit resistance when power supply is connected to terminal B (shunt start).
Cooling ......
....................................
Combination Self-Cooled & Blast Air
Air Inlet Opening Diameter .......................................................................................................
3.00 inches
Overall Length (Less Spline Drive) ........................................................................................ 00 inches
Housing Diameter ...............................................................................................................
86 inches
Weight (Including QAD Kit)* (Approx) ...................................................................................
55 pounds
Overhung Moment (Approx).............................................................................................153
inch-pounds
Direction of Rotation (Viewing Drive End) ......................................................................
Counterclockwise
Drive Spline & Mounting Flange...............................................................................
MS3331-1 P
Number of Teeth in Drive Spline ..............................................
....
12
Drive Spline Pitch Diameter ............................................... ...
.... 0.600 inch
Drive Shaft Shear Torque (Nom.) .................................................................
1,600 inch-pounds
Terminal Designations
Positive....................................................................................B+
Negative ........................................................................................
E-
Positive Field .....................................................................
A+
Equalizer ........................................................
........... ..D
EFFECTIVITY:
040-999
PAGE 7
24-30-00
Jan
10/90