Twin City Axial Roof Ventilators and Tubeaxial Fans - IM-4000 - Manual (Page 5)

Twin City IM-4000 5
Fan bearings on belt driven fans should not need to be
replaced for many years if the previous recommenda-
tions are strictly adhered to. However, use the following
procedure when bearing replacement is necessary.
1. Gain access to the fan bearings. Remove the bear-
ing cover, if any.
2. Loosen the belts by shifting the motor.
3. Remove the propeller or wheel and disconnect the
remote lube lines (if applicable).
4. Measure the location of the bearing to the propeller
or wheel 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 or wheel may
need to be temporarily installed to get its clearances
equal.)
12. Lubricate bearings. See Table 3, Page 3.
13. Tighten setscrews in steps (alternating half turns).
Note torquing requirements with bearing instructions.
14. Tighten the bearing mounting bolts.
15. Reinstall the lube lines (if applicable).
16. Install bearing cover, propeller and belts and adjust
the motor to get proper belt tension. Also, make
sure that the sheaves are properly aligned.
17. 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 fre-
quency 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 perfor-
mance. Any serious deviations could indicate a potential
motor failure.
All motors have prelubricated 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.