Alternator Belt Inspection - Lycoming TEO-540-C1A Maintenance Manual

2. Alternator Belt Inspection

A. Examine the alternator belt (Figure 1) for any cracks, damage, or wear.
B. Complete the "Alternator Belt Tension Check/Adjustment" procedure in this chapter.
C. Replace a worn, cracked or damaged alternator belt per instructions in the "Alternator Belt
Replacement" section in this chapter.
Alternator Assembly, Alternator Belt, and Starter Ring Gear
3. Alternator Belt Tension Check/Adjustment
CAUTION IF THE ALTERNATOR BELT TENSION IS NOT SET CORRECTLY, THE
ALTERNATOR BELT CAN SLIP, WEAR PREMATURELY, AND
DECREASE ELECTRICAL OUTPUT.
A. When to complete an alternator belt tension check.
(1) Immediately after the alternator belt is replaced and then after 25 hours of operation after
installation.
(2) During each 100-hour service inspection thereafter.
B. Use either of the following methods to complete an alternator belt tension check:
• Deflection Method
• Belt Tension Gage Method
(1) Deflection Method
(a) Attach the hook of a small spring-scale to the alternator belt at the approximate mid-
point between the ring gear support and the alternator.
(b) Pull on the scale until a reading of 14 lb. (6.4 kg), is shown for a new belt.
(c) Measure the distance the alternator belt has moved with the 10 or 14 lb. (4.5 to 6.4
kg) load applied.
(d) The distance (deflection) is to be 5/16 in. (7.94 mm). If less than 5/16 in. (7.94 mm),
the alternator belt tension is too tight.
(e) Adjust the belt tension as required to get the 5/16 in. (7.94 mm) distance (deflection)
per the "Alternator Belt Tension Adjustment" procedure for the respective alternator
in this chapter.
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TEO-540-C1A Engine Maintenance Manual
TEO-540-C1A Engine Maintenance Manual
Figure 1
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November 2018