On Saturday, 25 March 2017 12:31:46 UTC, Graham. wrote:
On Sat, 25 Mar 2017 10:44:04 +0000, Tim Lamb
wrote:

Bosch drive motor failure on spin function. Failed to reach full speed
and then tripped out the house RCD.

Google seems to imply this is terminal for the motor. On examination the
carbon brushes have worn to the point where the copper inserts have
marked the commutator.

Set of brushes are cheap enough but replacing the motor at 175-200ukp
seems poor economics.

Any experience?

AFAIK the flexible braided wire should be short enough not to allow
that to happen.

Treat it to some new brushes and if it continues to trip the RCD strip
it down, inspect, and clean the carbon deposits off the commutator,
brush carriers etc.

One needs to be thorough with the carbon, which can be slow. Last time I resurfaced a WM commutator by running it on 12v (IIRC) and using a file. Sometimes insulation trouble can be sorted out by mounting a motor on insulating mountings.


NT