1
2
2
3
1.
Straight edge
2.
Incorrect
3.
Correct
Figure 11: V-belt alignment
2.
When installing new belts, shorten center distance between sheaves so that belts can be put on
without the use of force. NEVER "roll" or "pry" the belts into place, as this could damage the belt
cords.
3.
Regardless of the belt section used, the belt should never be allowed to bottom in the groove. This
will cause the belts to lose their wedging action and slippage can occur. Sheaves or belts that per-
mit such a condition to occur should be changed.
4.
Proper belt tension is the primary reason for long belt life. Improper tension could cause belt fatigue
and/or hot bearings.
The general method for tensioning belts is given below, and should satisfy most drive requirements.
a) Reduce the center distance so that the belts may be placed over the sheaves and in the
grooves without forcing them over the sides of the grooves. Arrange the belts so that both the
top and bottom spans have about the same sag. Apply tension to the belts by increasing the
center distance until the belts are snug.
1
2
3
Figure 12: V-belt tension
b) Operate the drive a few minutes to seat the belts in the sheave grooves. Observe the operation
of the drive under its highest load condition (usually starting). A slight bowing of the slack side
of the drive indicates proper tension. If the slack side remains taut during the peak load, the
drive is too tight. Excessive bowing or slippage indicates insufficient tension. If the belts squeal
as the motor comes on or at some subsequent peak load, they are not tight enough to deliver
the torque demanded by the drive motor. The drive should be stopped and the belts tightened.
c)
Check the tension on a new drive frequently during the first day by observing the slack side
span. After a few days' operation the belts will seat themselves in the sheave grooves and it
may become necessary to readjust the drive to show a slight bow in the slack side.
Other methods of determining proper belt tension can be obtained from the drive manufacturer.
5.
Belt guards protect personnel from danger and the drive from contamination. Inspect periodically to
assure that belts do not rub against guard.
6.
Dirt and grease reduce belt life. Belt dressing affects performance only temporarily and is NEVER
recommended. Maintaining a clean drive is better practice.
If any questions arise pertaining to the drive limitations, consult the drive manufacturer.
4.1 Pre-installation
24
Model Trash Hog II Installation, Operation, and Maintenance Manual