Noisey brushed motor

Ed, Does the motor have a cooling fan because this is usually the source of the noise. This is where the fan blade hits the air of the previous blade causing the noise. If the fan has un evenly distributed blades then this is to help stop the noise.

Martin P

Ed,

The noise is the commutator - I expect a combination of mechanical noise and the small arcs that form when the brushes slide from one winding to the next. Induction motors have no commutator or sliding parts other than the bearings, so don't make the high-pitched whine of universal motors.

You could attach a padded barrel over the chassis, or fit a power control to reduce the speed. If the commutator isn't shiny and smooth, you could skim a few thou off in the lathe, and polish the brush faces in situ (wet 'n' dry wrapped around the commutator?)

Yup!

HTH Guy

Its the brush gear that causes the noise, also the fact that a brush motor runs considerably faster than an induction motor. Usually 1425 or 2850 induction speeds. For example a Hotpoint automatic washing machine motor (electronically controlled) will run up to 10,000rpm un-controlled. The brushes are set "off" centre to give more surface area in the main direction for spinning. I have tried practically everything to quieten these down with little success. Skimming the commutator has its own problems in that you HAVE to remove all burrs from the segments and having done so it leaves a sharp edge for the brush to run over (more noise) Some of those Flymo motors made by EMD have the segment gaps filled with insulating material, that's as quite as they get.

Daz