Called to a site today to look at a 7500Kw slip ring motor. Stator is 6kv and rotor is 2.5kv. Problem is that the brushes on the centre slip ring are running so hot they are 'welding' themselves into the brush boxes before being due for replacement. Carried out 'Surge' tests, Hi-Pot tests, Ducter resistance tests and motorised megger tests. All test results were satisfactory and I can find no reason for these brushes burning the way they do. Does anyone have any ideas? 12 new boxes and 36 new brushes have been fitted, bedded in and all boxes aligned and now I will keep a weekly check on them for the forseeable future but if it starts doing it again it would be nice to be able to explain to the customer what the problem may possibly be. As you would imagine, taking a machine this big out of situ for repair would be VERY expensive!
Thanks in advance.
Thanks in advance.