Twin City IM-4800
11
Fan bearings on belt driven fans should not need to be
replaced for many years if the previous recommendations
are strictly adhered to. However, use the following
procedure when bearing replacement is necessary.
1. Gain access to the fan bearings. Remove the
bearing cover, if any.
2. Loosen the belts by shifting the motor.
3. Remove the propeller and disconnect the remote
lubrication tubes (if applicable).
4. Measure the location of the bearing to the propeller
end of the shaft and the bearing spacing.
5. Remove the shaft and bearing assembly. Note the
position of the bearings’ shims (if applicable).
6. Loosen all bearing/shaft setscrews or other locking
devices.
7. Remove bearings (may need to be pressed off the
shaft).
8. Polish the shaft with fine emery paper (240 grit or
finer) and file the setscrew dimples left on the shaft
flat.
Bearing Replacement
Motors
9. Install new bearings on the shaft, making sure that
the collars are together (i.e. facing each other on the
shaft). Lightly seat one setscrew or eccentric locking
collar on each bearing to hold in the approximate
marked position.
10. Mount the shaft/bearing assembly in the fan with
bolts. Do not tighten yet. Just snug up. Loosen the
setscrew.
11. Center the shaft in the housing (both ends) as
closely as possible. (The fan propeller may need to
be temporarily installed to get its clearances equal.)
12. Tighten the bearing mounting bolts.
13. Reinstall the lube tubes (if applicable).
14. Install propeller and belts and adjust the motor to
get proper belt tension. Also, make sure that the
sheaves are properly aligned.
15. If a new shaft is supplied, ignore items 6 thru 8.
Twin City Fan & Blower recommends periodic checks
of voltage, frequency and current of a motor while
in operation. Such checks assure the correctness of
frequency and voltage applied to the motor, and yield
an indication of the fan load. Comparison of this data
with previous data will give an indication of the fan
performance. Any serious deviations could indicate a
potential motor failure.
All motors have pre lubricated sealed bearings and are
lubricated for the life of the motor.
1. All motors carry a one-year limited warranty from date
of shipment. For repairs within the warranty period,
the motor must be taken to the motor manufacturer’s
authorized service dealer. Contact your representative
for additional warranty details.
2. A periodic motor check should consist of spinning
the motor shaft with the power off to be sure the
motor turns freely and the bearings run smoothly. The
belt on belt driven units should be removed from the
motor pulley.
Repair or replacement of motors is normally performed
by a repair station authorized by the manufacturer.
Contact your representative or the factory for locations
nearest you. DO NOT ship motor to the factory without
specific authorization forms.
Table 3. Suggested Fan Bearing Greasing Intervals
Table 4. Grease Manufacturers
MANUFACTURER
GREASE (NLGI #2)
Shell
Gadus S2 V100 2
Exxon/Mobil
Ronex MP
INTERVAL
(MONTHS)
TYPE OF SERVICE
12 to 18
Infrequent operation or light duty in
clean atmosphere
6 to 12
8 to 16 hrs./day in clean, relatively dry
atmosphere
3 to 6
12 to 24 hrs./day, heavy duty, or if
moisture is present
1 to 3
Heavy duty in dirty, dusty locations; high
ambient temperatures; moisture laden
atmosphere; vibration
