T i m wrote:
On Mon, 21 Jan 2008 22:54:09 -0000, "Harry Bloomfield"
wrote:

"T i m" wrote in message
...
On Mon, 21 Jan 2008 22:02:03 +0000, The Natural Philosopher
wrote:

The actual windings are very low ohms of course (7 or so) so this 18k
obviously isn't a winding directly shorting on the frame so insulation
breakdown seems likely, however, I'm still hoping that there is some
carbon brush build up actually between where the flex joins the
winding and that a wash off might sort it (I said hopefully ...) ;-)
I too would be inclined to try giving the stator windings a wash down, you
have nothing to loose.

Apart from time and I have more of that than money at the moment ;-)

It might be as simple as the exposed bare wire at the
joint - as per your own suggestion.

Or even a loose insulating sleeve with carbon powder stuck up it and
across to the motor frame. I think the stator is sitting on a plastic
bobbin so in theory it shouldn't be in direct contact with the motor
frame anywhere and ignoring this RCD issue seems to run ok.

Out of curiosity, what fluid were you
thinking of using for the actual 'wash'?

Good question Harry. This morning I had intended buying some paraffin
and a metal bucket (or finding a suitable metal / fuel proof
container) and giving the whole motor a good dunking.

Or wondering if I could afford an ultrasonic tank big enough to hold
the complete motor.

Instead I blew it through with my mates airline and washed the
business end out with some brake cleaner (I think it has naphtha as
one of the ingredients) and that seemed to work ok. After I had dried
/ blown it out I re greased the brush end bearing (spray grease in
beside the bearing shield) and span it up to work the grease in and
re-fitted the cleaned / blown out brush holders (and that cct measures
ok).

I initially thought I needed something cheap / safe enough to be able
to submerge the entire motor that would neither affect the insulation
nor plastic bits but be 'solventy' enough to shift the carbon (hence
the paraffin)?

What would you suggest?

All the best ..

T i m

p.s. I think I've found a couple of site selling new motors and they
are around 220 quid! I wonder if a local motor 're-winder' would do it
cheaper?


find a place that does *exchange* motors.