11-16 ALTERNATOR SERVICE TEST SPECIFICATIONS. Refer to Figure 11-14. for test circuit used.
Prestolite specifications for the 14-volt alternators installed as original equipment are as follows:
TABLE Xl-ll. ALTERNATOR SPECIFICATIONS
11-17. CHECKING ALTERNATOR BELT TENSION. If properly installed, tensioned and checked periodically,
the alternator drive belt will give very satisfactory service. However, an improperly tensioned belt will wear
rapidly and may slip and reduce alternator output. Consequent1y, a belt should be checked for proper tension at
the time it is installed, again after 25 hours of operation and at each 100 hour inspection thereafter.
The torque method for checking alternator belt tension is given as follows:
a. Apply a torque indicating wrench to the nut that attaches the pulley to the alternator and turn it in a
clockwise direction. Observe the torque shown on the wrench at the instant the pulley slips.
accordingly.
TABLE XI-III. ALTERNATOR BELT TENSION
Alternator Model
ALY 6421 6422
Voltage
12-volts
Rated Output
60 amperes
Ground Polarity
Negative
Rotation
Bi-Directional
Rotor (70° to 80° F):
Current Draw
2.4 to 4 0 amps @ 12.0-volts
Resistance
3.5 to 5.0 ohms
Output Test (70° to 80° F):
Volts
14.0
14.0
Amperes Output
13 0
47.0
Alternator RPM
2000 min
4000 max
Torque indicated at
Width of Belt
Condition
alternator pulley
3/8 inch
New
11 to 13 ft-lbs
3/8 inch
Used
7 to 9 ft-lbs
PIPER AIRCRAFT
PA-28-161 CADET
AIRPLANE MAINTENANCE MANUAL
Issued: FEBRUARY. 28, 1989
ELECTRICAL SYSTEM
2D8