User guide

4
Belt and Pulley Installation
Belt tension is determined by the sound of
the belts when the fan is first started. The
belts will produce a loud squeal, which dissi-
pates after the fan is operating at full capacity.
If belt tension is too tight or too loose, lost
efficiency and damage may occur.
Do not change the pulley pitch diameter to
change tension. The change will result in a
different fan speed.
1. Loosen motor plate adjustment bolts and slide motor
plate so that belts easily slip into the grooves on the pul-
leys. Never pry, roll, or force the belts over the rim of the
pulley.
2. Slide motor plate until proper tension is reached. For
proper tension, a deflection of approximately 1/4” per
foot of center distance should be obtained by firmly
pressing the belt. Refer to Figure 1.
3. Lock the motor plate adjustment bolts in place.
4. Ensure pulleys are properly aligned. Refer to Figure 2.
Pulley Alignment
Pulley alignment is adjusted by loosening the motor pulley
setscrew and by moving the motor pulley on the motor shaft.
Figure 2 indicates where to measure the allowable gap for
the drive alignment tolerance. All contact points (indicated
by WXYZ) are to have a gap less than the tolerance shown
in the table. When the pulleys are not the same width, the
allowable gap must be adjusted by half of the difference in
width. Figure 3 illustrates using a carpenter’s square to
adjust the position of the motor pulley until the belt is parallel
to the longer leg of the square.
Bearing Replacement
The fan bearings are pillow block type ball bearings.
1. Remove the old bearing.
2. Remove any burrs from the shaft by sanding.
3. Slide new bearings onto the shaft to the desired loca-
tion and loosely mount bearings onto the bearing sup-
port. Bearing bolts and setscrews should be loose
enough to allow shaft positioning.
4. Correctly position the wheel and tighten the bearing
bolts securely to the bearing support.
5. Align setscrews bearing to bearing and secure tightly to
the shaft.
NOTICE! Never tighten both pairs of setscrews
before securing bearing mounting bolts. This may
damage the shaft.
6. Inspect the wheel position again. If necessary, readjust
by loosening the bearing bolts and setscrews and repeat
from step e.
Tolerance
Center Distance
Maximum
Gap
Up thru 12” 1/16”
12 up through 48” 1/8”
Over 48” 1/4”
Figure 2
OFFSET ANGULAR OFFSET/ANGULAR
A
W
X
Y
Z
B
CENTER
DISTANCE
(CD)
GAP
GAP
Motor Services
Should the motor prove defective within a one-year
period, contact your local Loren Cook representative or
your nearest authorized electric motor service represen-
tative.
Changing Shaft Speed
All belt driven ventilators
(5HP or less) are equipped
with variable pitch pulleys.
To change fan speed, per-
form the following:
a. Loosen setscrew on
driver (motor) pulley and
remove key, if equipped.
b. Turn the pulley rim to
open or close the
groove facing. If the pul-
ley has multiple
grooves, all must be
adjusted to the same width.
c. After adjustment, inspect
for proper belt tension.
Speed Reduction
Open the pulley in order that
the belt rides deeper in the
groove (smaller pitch diameter).
Speed Increase
Close the pulley in order that
the belt rides higher in the groove (larger pitch diameter).
Ensure that the RPM limits of the fan and the horsepower
limits of the motor are maintained.
Replacing Pulleys and Belts
1. Clean the motor and fan shafts.
2. Loosen the motor plate mounting bolts to relieve the
belt tension. Remove the belt.
3. Loosen the pulley setscrews and remove the pulleys
from the shaft. If excessive force is required to
remove the pulleys, a three-jaw puller can be used.
This tool, however, can easily warp a pulley. If the
puller is used, inspect the trueness of the pulley after
it is removed from the shaft. The pulley will need
replacement if it is more than 0.020 inch out of true.
4. Clean the bores of the pulleys and place a light coat
of oil on the bores.
5. Remove any grease, rust or burrs from pulleys.
6. Place the fan pulley on the fan shaft and the motor
pulley on the motor shaft. Damage to the pulleys can
occur when excessive force is used in placing the pul-
leys on their respective shafts.
7. After the pulleys have been correctly placed back
onto their shafts, tighten the pulley setscrews.
1 foot
1/4 inch
Figure 1
ACSC-HP
Size
Maximum RPM
Standard Reinforced
150 1952 -
165 1728 -
180 1829 -
195 1570 -
210 1626 -
225 1435 -
245 1185 1234
270 1025 1049
300 980 1046
330 830 912
365 735 872
ACSC-XP
Size
Maximum RPM
165 2508
180 2396
195 2100
210 2126
225 1879
245 1616
270 1656
300 1391
330 1182
365 1132
Figure 3