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damage to the belts. Tension in V-belts should be such that when
the drive is idle the belts appear snug, and when drive is under full
speed and load, a slight sag is noticeable on the slack side. Vertical
drives, extremely short center high ratio drives, and drives carrying
pulsating loads need additional tension.
Maintenance and operating practices. V-belts require very
little maintenance, but lack of attention to the following items will
result in reduced service life:
a. Lubricate the bearings of sheave and idler shafts to
prevent freezing.
b. Maintain operating tension by periodic adjustment of
centers of idlers. Changes take place more rapidly when new belts
are first installed, and these should be checked after 24 and 48
hours of operation.
c. Keep the shafts parallel, sheaves in alignment and running
true. Excessive wobble or eccentricity may result in vibration and
overload and cause damage to the belts.
d. Do not permit the belts to rub or strike splinters, spikes,
sharp edges or belt guard while operating.
e. Keep belts and sheaves reasonably free of lubricating oil
and other foreign material.
f. Belt dressing should not be used with V-belts. If slippage
occurs due to an oily or dirty condition of belts or sheaves, both
the belts and the sheaves should be thoroughly cleaned with a cloth
and volatile cleaning fluid.
g. The practice of using a pipe wrench to turn a sheave by
hand should be avoided, as the groove ribs can be severely
damaged.
h. Extremely rough, broken or chipped grooves result in
reduced belt life. Worn sheaves should be regrooved.
i. Dampen impulse loads as much as possible by balancing
the equipment. Belt vibration may often be reduced or eliminated
by slight changes in speed or tension.

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