NOTICE BOARD
TECHNICAL PAGE 2

PICTURE GALLERY 1 MECHANICAL FAILURE

The picture (left) shows the non drive end bearing of a 15 kW  high output motor. The outer bearing shield is still intact but  badly contaminated. This contamination has entered the bearing and caused it to seize. The inner metal shield and the cage containing the rolling elements has burst, damaging the windings.
The picture (right) shows the other side of the bearing. The shield has disintegrated and damaged the windings. The cage has broken up and you can see part of it sticking out of the bearing at top centre. The discolouration on the rotor is carbon which formed when the windings blew.
There is heavy contamination in the bearing housing (left). You can see brown marks on the edge of the housing and on the bearing’s outer ring (above right). This suggests that when the bearing started to seize, the outer ring was turning in the housing causing wear.
The picture  on the right shows a heavy carbon deposit on the windings giving the appearance of a burn out however the other end of the windings are almost like new. This confirms a blow in the windings on the non drive end.

 

In the picture (left), on close inspection small copper splatter can be seen on the winding and between the winding and the casing. Also open circuits in the copper wires can be seen. A great deal of this damage could have been avoided with proper checks and maintenance.

 

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