COOK IMH - Manual (Page 7)

7
e. Remove burrs from shaft by sanding.
f. Place fan pulley on fan shaft and motor pulley on its
shaft. Damage to the pulleys can occur when exces-
sive force is used in placing the pulleys on their
respective shafts.
g. Tighten in place.
h. Install belts on pulleys and align as described in the
Belt and Pulley Installation section.
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
a. Remove pulleys from their respective shafts.
b. Clean the motor and fan shafts.
c. Clean bores of pulleys and coat the bores with heavy
oil.
d. Remove grease, rust, or burrs from the pulleys and
shafts.
e. Remove burrs from shaft by sanding.
f. Place fan pulley on fan shaft and motor pulley on its
shaft. Damage to the pulleys can occur when exces-
sive force is used in placing the pulleys on their
respective shafts.
g. Tighten in place.
h. Install belts on pulleys and align as described in the
Belt and Pulley Installation section.
Bearing Replacement
The fan bearings are pillow block ball bearings.
An emery cloth or file may be needed to remove imper-
fections in the shaft left by the setscrews.
a. Mark the position on the shaft of both bearing races,
setscrews, and the wheel and pulley. Note the clear-
ance between the wheel and inlet.
b. Remove the fan pulley and belts.
c. Remove the inlet side panel by removing the bolts
around the perimeter of panel.
d. Remove inlet cone by removing attaching bolts/nuts
around perimeter of the inlet plate.
e. Remove wheel from the shaft. A 2-jaw puller may be
needed.
f. Remove bearing hold-down bolts. Remove shaft and
bearings as one unit.g. Remove the anti-corrosion
coating from the shaft with a suitable degreaser.
RPM Derating Factor
For elevated airstream temperatures, the maximum RPM limits must be derated
by the factors found in the RPM Derating Factor table above.
Steel Aluminum
Temp. °F RPM Temp. °F RPM
70 1.00 70 1.00
200 .98 200 0.93
300 .96 300 0.79
400 .94
500 .91
600 .87
700 .81
800 .75
h. Remove the bearing from the shaft using a bearing
puller. If a bearing puller is not available, tap on the
bearing with a wood block and hammer to remove it.
i. Smooth and clean the shaft and bearing bore thor-
oughly.
j. Place the bearings into position making sure they are
not on a worn section of the shaft. Tapping the inner
ring face with a soft driver may be required.
Do not hammer on the housing.
k. The outer ring of the bearing is spherical and swivels
in the housing to compensate for misalignment.
Secure hold-down bolts, but do not fully tighten.
l. Align the setscrews on the bearings and tighten one
setscrew on each bearing.
m. Rotate the shaft to allow the bearing outer rings to
find their center of free movement.
n. Install the wheel on the shaft and install the inlet side
panel in its original location. Adjust bearing position
and inlet side panel to center the wheel in the inlet.
o. Tighten bearing hold-down bolts to proper torque.
Refer to Torque Chart.
p. Turn the shaft by hand. Resistance should be the
same as it was before hold-down bolts were fully tight-
ened.
q. Tighten bearing setscrews to specified torque as
noted in the Torque Chart.
r. Reinstall the pulley and adjust the belt tension. Refer
to Belt and Pulley Installation.
s. Test run the fan and trim balance as necessary (.0785
in/sec max.).
t. Re-tighten setscrews on bearings, sheave, and wheel.
Recheck belt tension and adjust as needed.
Troubleshooting
Problem and Potential Cause
Low Capacity or Pressure
•Incorrect direction of rotation. Make sure the fan rotates in same
direction as the arrows on the motor or belt drive assembly.
•Poor fan inlet conditions. There should be a straight clear duct at
the inlet.
•Improper wheel alignment.
Excessive Vibration and Noise
•Damaged or unbalanced wheel.
•Belts too loose; worn or oily belts.
•Speed too high.
•Incorrect direction of rotation. Make sure the fan rotates in same
direction as the arrows on the motor or belt drive assembly.
•Bearings need lubrication or replacement.
•Fan surge or inlet or outlet conditions.
Overheated Motor
•Motor improperly wired.
•Incorrect direction of rotation. Make sure the fan rotates in same
direction as the arrows on the motor or belt drive assembly.
•Cooling air diverted or blocked.
•Improper inlet clearance.
•Incorrect fan RPMs.
•Incorrect voltage.
Overheated Bearings
•Improper bearing lubrication
•Excessive belt tension.