Page 330 - Practical Machinery Management for Process Plants Major Process Equipment Maintenance and Repair

Chapter 7

V=Belt Drives*

Well designed and properly installed V-belt drives are without question
among the most reliable, trouble-free means of power transmission avail-
able. In general, except for an occasional retensioning, many will liter-
ally run for years without maintenance,
However, some V-belt drives do require periodic inspection and main-
tenance, both while the drive is running and while it is stationary.

lnspectlon While Running

A noisy V-belt drive is like a person with a fever. Both need attention.
V-drive noise can be caused by the slapping of belts against the drive
guard or other obstruction. Check for an improperly installed guard,
loose belts, or excessive vibration. Squealing of belts as a drive is started
or while it is running is usually caused by a poorly tensioned drive and/or
by a build-up of foreign material in the sheave grooves. But it can also be
caused by oil or grease between the belt and the sheave groove.
If necessary, remove the belt guard and watch the drive while it is run-
ning under load. (Curcrion: Observe only; stud clear of the running
drive!) Much can be learned by watching the action of the slack side of
the drive. Each variation in the driven load causes a corresponding
change in the tension of the slack side of the belt. During across-the-line
starts or suddenly applied loads while running, the sag on the slack side
of the drive will increase. If the sag under these conditions is excessive,
tension should be increased.

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* Source: T. B. Mods Company, Chambersburg, Pa. Their permission to use this mate-
rial is gratefully acknowledged.
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