circular saw problem?

"Stephen" wrote in news:z8idnZ2PkK1 snipped-for-privacy@brightview.co.uk:

I had a similar problem with my Makita 6095 drill/driver. (blue sparking) I used CRC MAF-sensor spray cleaner to wash out the powdered graphite on the commutator tht was left over from the worn brushes. No more sparking.

yellow sparking would seem to indicate some sort of ferrous metal burning. maybe it needs lube,if the bearings aren't too far gone.

Or shorts to the iron of rotor or stator which explains the original and replacement brushes, blue sparks from excess rotor current

The tale deepens....

as mentioned before I had recently replaced the brushes. This was after serious use involving fitting a kitchen, bathroom, garden fence, chopping up old fencing and old wood windows for fire wood etc etc.

I have not had as much use on the second brushes. Today I have inspected them One is half worn and the other is completely worn down to the springs.....

Stephen.

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So a fault leading to more current than the brushes are designed for and/or rough/broken/accreted commutator lands

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Doesn't a 'shorted' turn on a motor burn out brushes?

Usually accompanied by loss of torque.

"Stephen" wrote in news: snipped-for-privacy@brightview.co.uk:

sounds like your commutator is damaged and is abrading the brushes too quickly. often,commutators are turned smooth before replacing the brushes.