That Blower problem again!!!

[kemik007]

Finally got round to looking at the wifes 406 td fan problem at the w/e, the usual move the wires it worked/let go it stopped!!!

Undid the 3 screws and removed the orange? coloured 4 wire plug and took it to the shed.

Sprised the motor from the housing (gently) with 2 large flat bladed screw drivers under the fan between the housing.

Removed the 3 rubber mounts off the motor case.

removed the small silver brush caps with a small flat bladed driver.

removed the brush springs and eased out the brushed they looked a bit worn but still had about 1/4 inch left

noticed that the commutator (the bit that the brushes sit on) was worn and a bit burnt.

cut a few pieces of different grade emery cloth about 1" x 1/2" long and doubled it over bent it round the end of a 1/4" x 1" bolt and pushed it down the brush holder.
Held in place with an elastic band.

Got my battery drill on the fan end and after 1/2 hour of spinning and changing the emery cloth the polishing the com was done, not perfect but shiney enough.

Vacuumed out the dust and re assembled the motor ( make sure the brushes go back in the same way you took them out)

Put a bit of washing up liquid on the rubbers and re assembled the fan.

Replaced the unit and its working a treat

Job took about a hour

Hope it helps some one in the future!!

Steve

[Doggy]

Nice improvised commutator skim there, sir!

That's more or less the way to do it. You should really 'undercut' the insulation between the comm segments afterwards - this is to ensure the copper is 'proud' of the insulation and to prevent any conductive matter 'hiding' in the slots. (Most people improvise a tool for this by grinding the set off a bit of hacksaw blade).

Good blow out (or thorough vacuum) gets rid of all the carbon brush you didn't find......

Another dodge that can work is to make a set of brushes out of any that are physically bigger than the originals, though finding a grade suitable for the current density is a bit of a lottery...

Nice How-To

[FarmerPug]

that sounds like something for the knowledge base a good guide indeed

[kemik007]

I know all about com skimming from my apprentice days, undercutting was one task to avoid like the plague!!!! hours spent with a hacksaw blade in a handle cutting
the mica between the coppers. I wrote the guide as a quick fix that might work for some fans without having to dismantle the motor too far.

By all means post it in the Knowlege database if it helps someone from spending £100 for an hours work its worth it.

Steve