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 Bearings1.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.

Type

Operating

Grease Quantity*

Bearing

(End Caps)

Bearing

(Shaft)

Outer

Inner

 

Deep Groove

Horizontal

2/3 Full

1/3 Full

Ball

 

 

 

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

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