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4- The blower RPM can be adjusted at the motor pulley.
Loosen Allen screw and turn adjustable pulley clock
wise to increase CFM. Turn counterclockwise to de
crease CFM. See figure 7. Do not exceed minimum and
maximum number of pulley turns as shown in table 1.
TABLE 1
MINIMUM AND MAXIMUM PULLEY ADJUSTMENT
Belt
Minimum
Turns Open
Maximum
Turns Open
A Section No minimum 5
B Section 1* 6
*No minimum number of turns open when B belt is used on
pulleys 6” O.D. or larger.
Blower Belt Adjustment
Maximum life and wear can be obtained from belts only if
proper pulley alignment and belt tension are main
tained. Tension new belts after a 24-48 hour period of op
eration. This will allow belt to stretch and seat grooves.
Make sure blower and motor pulley are aligned as shown in
figure 8.
FIGURE 8
PULLEY ALIGNMENT
BELT
BLOWER
PULLEY
MOTOR
PULLEY
NOT ALIGNED
ALIGNED
1- Loosen four bolts securing motor base to mounting
frame. See figure 7.
2- To increase belt tension -
Turn adjusting bolt to the right, or clockwise, to move
the motor outward and tighten the belt. This increases
the distance between the blower motor and the blower
housing.
To loosen belt tension -
Turn the adjusting bolt to the left, or counterclockwise
to loosen belt tension.
IMPORTANT - Align top edges of blower motor base and
mounting frame base parallel before tightening two bolts on
the other side of base. Motor shaft and blower shaft must be
parallel.
3- Tighten bolts on side of base.
Check Belt Tension
Overtensioning belts shortens belt and bearing life. Check
belt tension as follows:
1- Measure span length X. See figure 9.
2- Apply perpendicular force to center of span (X) with
enough pressure to deflect belt 1/64” for every inch of
span length or 1.5mm per 100mm of span length.
Example: Deflection distance of a 40” span would be
40/64” or 5/8”.
Example: Deflection distance of a 400mm span would
be 6mm.
3- Measure belt deflection force. For a used belt, the
deflection force should be 5 lbs. (35kPa). A new belt
deflection force should be 7 lbs. (48kPa).
A force below these values indicates an underten
sioned belt. A force above these values indicates an
overtensioned belt.
MEASURE BELT TENSION
FIGURE 9
DEFLECTION 1/64” PER INCH OF SPAN
OR 1.5mm PER 100mm OF SPAN
FORCE
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