On Mon, 7 May 2018 13:20:16 +0100, "Dan S. MacAbre"
wrote:

Archibald Tarquin Blenkinsopp wrote:
On Mon, 7 May 2018 12:14:16 +0100, "Dan S. MacAbre"
wrote:

The washing machine packed in this morning. Filled up with water, and
then nothing. I expected I was going to need to replace the motor
brushes (although they're only about two years old), but they are still
quite long. I noticed that the commutator lands (or whatever you call
them) were blackened, and that the face of one of the brushes was quite
rough, like anthracite. I also remembered that last night, it was
making what I now realised was an arcing noise, and not a chattering
noise that I'd normally associate with the brushes getting too short.
Anyway, I cleaned them up, and it's working fine now, but I'm wondering
what caused it. Is one of the brushes malformed? Or has low spring
pressure? Or something else?

If you have replaced the brushes previously did you use like for like.


I bought brushes that were supposed to be the correct replacement for
the model (i.e. they were ostensibly identical to the old ones); but I
realise that there is always going to be 'good' and 'bad' stuff out
there, and that one pretty much takes one's chance when buying things
online. I've never seen one with such a burnt appearance before,
though. Even when worn right down, all the old brushes I've seen in the
past have a shiny surface.




Assuming the brushes were identical, can the suppression caps be
changed or swopped?

If you can fire up the motor while watching the aramature/ commutator
it might save a bit of work dismantling the thing a second time.

It probably is the brush, but if it's fairly easy to swop the caps to
see if the arcing follows the cap change, then it eliminates the only
other possibility.

AB