ABB AMA Series, Manual

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Manual for Induction Motors and Generators
76 - Maintenance 3BFP 000 050 R0101 REV E
end bearing insulation resistance test, to remove the drive-end bearing shells or the bearing
shield and to lift the shaft. This ensures that there is no electrical contact between the shaft and
any other part, for example, frame or bearing housing.
Figure 7-2 D-end bearing earthing cable
For all machines any optional shaft earthing brush, rotor earth fault brush and coupling (if it is
made out of conductive material) must be removed. Measure the insulation resistance from the
shaft to earth using no more than 100 VDC, see
Figure 7-3 Measuring the insulation resistance
of a sleeve bearing and Figure 7-4 Measuring the insulation resistance of a roller bearing . The
measuring points over the bearing insulation are circled in the figures.
The insulation resistance is acceptable if the resistance value is more than 10 k
Ω.
Figure 7-3 Measuring the insulation resistance of a sleeve bearing