Re: Traction Motors

[craigd@lios.apana.org.au (C. Dewick)]

In <37F9525B.7B39DE3F@ozemail.com.au> David Johnson <trainman@ozemail.com.au> writes:

>Gareth Lumsden wrote:

>> What causes EMU traction motors of the same type/make to be noisier than
>> others?  Often parts of the carriage vibrate which aren't meant to, as a
>> result of "groaning" traction motors.

>I am fairly sure that it is the gear box that is vibrating.

David is right I think, but he hasn't really explained it... The effect you
describe is normally, afaik, caused because the pinion and main gears are
becoming worn, and this causes the gear teeth to move against each other
more unevenly than usual, especially when accelerating under power.

It can also be caused by armature bearings becoming 'dry' of lubricant,
resulting in excessive wear, but not 'dry' enough to cause heating and
eventual seizing. That does happen though it's normally described as a
'siezed pinion', which doesn't quite tell the true story, since it's
actually the armature shaft that is siezed. 8-)

If axle bearings become 'dry', they will usually start to whine, and
eventually heat up, and eventually sieze up first when the trains stops for
long enough that the metal cools down and contracts again.

Regards,

Craig.

-- 
            Craig Ian Dewick            |       Stand clear - jaws closing
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