A
HE, DE & RE MANUAL
IOM-26
27 of 33
Oct 12 R4
BELT ADJUSTMENT
For maximum belt and bearing life, pulley alignment and belt tension must be properly maintained. Only
replace with belts of the proper type and size.
NOTE: If belts are too tight or improperly aligned, the life expectancy of the motor(s), fan bearings and
belt(s) are reduced.
Alignment:
Pulleys must be aligned to within 1/16” per foot (1mm per 760mm) of span.
FOR FANS EQUIPPED WITH SPIDER BRACKETS:
A properly adjusted V-belt rides the inside of the pulley faces. Because the sides of the belt wedge in the
pulleys, the V-belt does not have to be extremely tight. It should be as loose as possible without slipping in
the pulley grooves.
Belt deflection: 3/4 “ (19mm) for each foot (300mm) of span between the pulleys.
FOR FANS EQUIPPED WITH PILLOW BLOCK BEARINGS:
Belt Deflection:
Allow 1/64” (0.4mm) of deflection for each 1” (25.4 mm) of span length.
CAUTION: Excessive belt tension is the most frequent cause of belt wear, bearing wear and noise.
SET SCREWS
Check set screws on fan wheel, fan bearings, fan and motor pulleys for looseness on the shaft. Tighten
where required. IT IS IMPORTANT TO PERFORM THIS CHECK BEFORE INITIAL START-UP, AFTER A
RUN-IN PERIOD OF 2 WEEKS AND THEN ON 4 MONTH INTERVALS.
CAUTION: OVERTIGHTENING SET SCREWS CAN DAMAGE BEARINGS.
DEFLECTION
SPAN
