Siemens 680 - Manual (Page 25)

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Maintenance
Sleeve Bearing
1120 Frame (See Figure 7)
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,
disengage the dowels, and remove 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 liner.
8. Reassemble, reversing the steps above. Apply
sealant. (See MAINTENANCE, SEALING PARTS
for proper sealing of this bearing design).Be
careful not to disturb or jam the seals when
replacing the upper half of the bearing capsule.
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, 580, 680 and 800
frames, the bearings are located axially by shims
between the bearing bushing and the bearing capsule
shoulders . On the 1120 frame, 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 7. Sleeve Bearing Construction
1120 Frame.