Piper SARATOGA PA-32-301 Maintenance Manual page 185

PIPER AIRCRAFT
PA-32-301/301T
MAINTENANCE MANUAL
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. Consequently. a belt should be checked for proper tension at the time it is installed. again
after 25 hours operation and each 100 hours thereafter.
- NOTE
For aircraft with air conditioning installed, refer to Chapter 21, for
replacement and adjustment of compressor drive belt.
There are two satisfactory methods of checking alternator belt tension; however. the first method
described will be found preferable by most maintenance personnel because it is technically simple and requires
little time for accomplishment.
1. Torque Method: This method of checking belt tension consists of measuring torque required to slip
the belt at the small pulley and is accomplished 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.
B. Check the torque indicated in Step A with torque specified in the following Chart 2404. Adjust
belt tension accordingly.
2. Deflection Method: Belt tension may be checked by measuring the amount of deflection caused by a
predetermined amount of tension. This is accomplished in the following manner:
A. Attach the hook of a small spring-scale tothe belt at the approximate mid-point between the rear
gear support and the alternator.
B. Pull on the scale until a reading of 14 pounds is obtained. (10 pounds for used belts.)
C. Measure the distance the belt has moved with the 10 or 14 pound load applied. The distance
(deflection) should be 5 16 inch. If less than 5 16 inch. the belt is too tight.
3. Upon completion of alternator belt tension adjustment. torque the alternator pivot bolts 225-255
inch-pounds.
CHART 2404. ALTERNATOR BELT TENSION - PRESTOLITE
Torque indicated at
Width of Belt
Condition
alternator pulley
3 8 inch
New
II to 13 ft.-lbs.
3 8 inch
Used
7 to 9 ft.-lbs.
12 inch
New
13 to 15 ft.-lbs.
12 inch
Used
9 to 11 ft.-lbs.
-NOTE-
The higher tension specified for a new belt is to compensatefor the
initial stretch that takes place as soon as it is operated. These higher
tension values should not be applied to belts which previously have
been used.
EFFECTIVITY: PRESTOLITE
24-31-12
Page 24-20
Revised: August 23. 1982
1H17