COOK AC - Manual (Page 5)

5
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 location
and loosely mount bearings onto the bearing support.
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 3.
Wheel Replacement
1. Drill two holes approximately centered between the
shaft and the edge of the hub OD with the following
dimensions:
• 1/4" diameter
• 3/8" to 1/2" deep
• 180° apart in face of hub
2. Tap 1/4" holes to 5/16" thread with the 5/16" hole tap.
Do not drill or tap any larger than recommended.
3. Screw the puller arms into the tapped holes full depth of
threads (3/8" to 1/2" approximately). Align center of
puller with center of shaft. Make certain all setscrews in
hub (normally a quantity of two) are fully removed. Work
puller slowly to back wheel off the shaft.
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
pulleys on their respective shafts.
7. After the pulleys have been correctly placed back onto
their shafts, tighten the pulley setscrews.
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 dissipates 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
pulleys. 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.
1 foot
1/4 inch Figure 1
OFFSET ANGULAR OFFSET/ANGULAR
A
W
X
Y
Z B
CENTER
DISTANCE
(CD)
GAP GAP
Figure 2
Tolerance Center Distance Maximum Gap
Up thru 12” 1/16”
12 through 48” 1/8”
Over 48” 1/4”
Figure 3