Installation manual

Page 70 IM-487
Figure 69. Fan Rotation
Once the fan has been put into operation, set up a periodic main-
tenance program to preserve the reliability and performance of
the fan. Items to be included in this program are:
• Belts
• Bearings
•Fasteners
•Setscrews
• Lubrication
• Removal of Dust/Dirt
Belts
Premature belt failures are generally caused by improper belt
tension (either too tight or too loose) or misaligned pulleys.
The proper tension for operating a V-belt is the lowest ten-
sion at which the belts will not slip peak load conditions. For
initial tensioning, the proper belt deflection half way between
pulley centers is 1/64" for each inch of belt span. For exam-
ple, if the belt span is 64 inches, the belt deflection should be
one inch using moderate thumb pressure at midpoint of the
drive, See Figure 70 on page 70.
Check belt tension two times during the first 24 hours of
operation and periodically thereafter. To adjust belt tension,
simply loosen four fasteners (two on each side of the motor
plate) and slide the motor plate away from the fan shaft until
proper belt tension is attained. On some fans, fasteners
attaching the motor to the motor plate must be loosened in
order to adjust the belt.
It is very important that the drive pulleys remain in proper
alignment after adjustments are made. Misalignment of pul-
leys will result in premature belt wear noise, vibration and
power loss, See Figure 71 on page 70.
Figure 70. Belt Adjustment
Figure 71. Drive Pulley Alignment
WARNING
Rotting fan and motor belts can cause severe
personal injury or death.
Secure all loose clothing, hair, jewelry and tools to avoid
entrapment.
A
i r f l o w
A i r f l o w
R o t a t i o n
R o t a t i o n
B e l t S p a n
D e f l e c t i o n =
B e l t S p a n
6 4
C e n t e r l i n e s
m u s t c o i n c i d
e
M u s t b e
p a r a l l e l
M u s t b e
p a r a l l e l
A d j u s t a b l e
S h e a v e
M o t o r
B e a r i n g