IM-5500
Installation, Operation & Maintenance Manual
12
Figure 1. Eliminate Slack
Figure 2. Belt Deflection
Figure 3. Alignment
Figure 4. Belts
Slack belts wear excessively, cause slippage and deliver less power.
For longest belt life, always provide proper tension.
Mount belts straight. Shafts must be parallel and sheaves in
alignment to prevent unnecessary belt wear.
Do not force belt. Forcing the belt will break the cords and
cause belt failure.
V-Belts
(refer to safety section)
V-belts on these belt driven fans are oil, heat and static resistant type and oversized for continuous-duty. With proper installation and
maintenance, years of operating efficiency can be added to the lifespan of the V-belt drive.
The condition of V-belts and the amount of belt tension should be checked prior to start-up (see Figure 1). When it becomes necessary
to adjust belt tension, do not over-tension as bearing damage will occur. Recommended belt tension should permit
1
/
64
" deflection per
inch of span of the belt at the center of the belt span. To find this point, measure halfway between the pulley centerlines as shown in
Figure 2. Extreme care must be exercised when adjusting V-belts as not to misalign the pulleys. Any misalignment will cause a sharp
reduction in belt life and will also produce squeaky, annoying noises (see Figure 3).
1. Always loosen tension adjustment enough to place belts on sheaves without running belts over the edge of either sheave. A new
belt may be seriously damaged internally by careless handling (see Figure 4).
2. Fan speed can be increased by closing the adjustable motor pulley or decreased by opening it. Always check the load on the motor
when increasing the fan speed.
When removing or installing belts, never force belts over pulleys without loosening the idler pulley or auto belt tensioner first to
relieve belt tension.
WARNING
Twin City Fan
