Siemens induction motors- generators cgii User Manual

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Maintenance
 
Bearing Replacement 
Antifriction Bearings 
For typical antifriction bearing configuration, see 
Figure 3. 
 
Replacement bearings may be of a different 
manufacturer but must be equal to the originals used in 
the motor.  When ordering bearings specify as follows: 
1.  The complete A.F.B.M.A. (Anti-Friction Bearing 
Manufacturers’ Association) bearing number from 
the motor nameplate. 
2.  Identifying numerals and manufacturer stamped on 
the bearing. 
3.  Bearing tolerance class, i.e. - A.B.E.C.-1 (Annular 
Bearing Engineers’ Committee Tolerance Class 
One). 
4. Internal radial clearance, i.e. – A.F.B.M.A.-3 
(Clearance Class Three).  
5.  Electric motor quality. 
 
To Replace Antifriction Bearings 
1.  Remove bolts holding end caps to housings. 
2.  Remove bolts holding bearing housings to yoke. 
3.  Remove bearing housings. 
4.  Remove the bearing with a puller. See Figure 4. 
5.  Check shaft and housing diameter for proper size 
with micrometer. 
6.  Heat the new bearing in an oven (200°F).  While 
it is hot, slide the bearing onto shaft – make 
certain that the inner race makes a firm even 
contact with shaft shoulder. Do not subject 
bearing to impact. 
7.  Let bearing cool - pack bearing caps with the 
proper grease.  
8.  Reassemble end caps and housings. 
 
The amount of grease to be used when repacking a 
bearing after cleaning or replacement is shown in the 
table below. 
Grease Quantity* 
(End Caps) 
Type 
Bearing 
Operating 
Bearing 
(Shaft) 
Outer Inner 
Deep Groove 
Ball 
Horizontal 
2/3 Full 
1/3 Full 
Roller 
Horizontal 
1/3 Full 
1/3 Full 
*
Pack all open bearings full between balls or roller but remove 
excess grease on outside of retainers.
 
 
 
 
Figure 3.  Ball Bearing Construction 
 
 
Protect the shaft end with a cap. If bearing is reusable, 
make certain the puller applies pressure against the 
bearing inner race only. If puller will not hook the bearing 
inner race, fabricate a split bushing and install it between 
the bearing and the puller hooks. 
 
Figure 4.  Removing Bearing with a Puller