708, 788, and 880 Frames (See Figure 8)
1.Check replacement bearings for nicks or shipping damage. Do not scrape.
2.Carefully remove the bearing housing cap by first lifting straight up, then pulling away from the bearing area.
3.Remove top half of bearing liner.
4.Remove the bolts at the split line of the oil ring.
5.Remove bearing temperature probes if so equipped.
6.Raise the shaft slightly and support it.
7.Rotate the lower bearing half 180° and remove the lower half of the bearing.
8.Reassemble, reversing the steps above. Apply sealant. The side faces of the labyrinth seals must be sealed with
9.Lubricate. Turn motor by hand to be sure of proper fit and oil ring operation.
10.Start motor without load and check oil ring operation.
End Float – Sleeve Bearings
Control of rotor end float in sleeve bearing motors is maintained in the drive end bearing. The total end float is 0.5 inch. On the 500 and 580 frames the bearings are located axially by shims between the bearing bushing and the housing shoulders in the lower half of the housing. On the 708, 788, and 880 frames the shims are located between the bearing housing mounting flange and the bearing bracket. The shims permit the bearing to be adjusted axially to maintain coincidence of electrical and mechanical center. Any adjustment of the axial position of one bearing should be accompanied by the same axial adjustment of the opposite end bearing.
The coupling should limit the end float of the shaft to ±0.18 inch from the mechanical center. The limited end float coupling prevents the rotor from rubbing against the bearing shoulders during operation.
Figure 8. Sleeve Bearing Construction
708, 788, and 880 Frames.
Spare Parts
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