Fitted brushes now motor sparking

Puzzled This page is about problems encountered after fitting new carbon brushes in a washing machine. If experiencing these issues without having just replaced the brushes though some of this article (and links) may still help.

Motor is sparking

A small amount of sparking is normal. Small sparks may occur until the carbon brushes bed in properly. Little minute sparks are often present but as long as they are very small should not indicate a problem. However, if there is a lot of sparking, particularly if it is flashing or arcing around the commutator then the repair is no good and you should stop using the washing machine before it blows something.

Have brushes been fitted correctly

The first thing to check is have the brushes been fitted correctly? It should be impossible to fit brushes the wrong way these days. The brushes come inside plastic holders. The holders are keyed so that they will only fit in the correct motor and the correct way. However, if for some reason someone has taken brushes out of their holders and manually put new ones in then they can be put the wrong way around.

Also, if someone has fitted the wrong brushes and forced them to fit or removed the keying stubs then you need to fit the proper brushes for the motor in question.

A correctly fitted brush has the curved end of the brush trailing against the commutator (the copper segments). If fitted the wrong way round then only the tip of the brush trails against the commutator instead. This would cause a loud ratchety sound and excessive sparking or lack of power.

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If brushes are fitted correctly, but you still have excessive sparking, especially big flashes, this is caused by poor contact between the brush and the copper segments they run on. This is usually because the commutator (copper segments) is worn or there’s a major fault on the armature. There’s nothing you can do except replace the armature – but as most manufacturer’s no longer supply new armatures – the entire motor.

In most cases now, new armatures can no longer be fitted and a complete new motor would be required. I would be cautious about buying an expensive motor unless you are very confident about the diagnosis and fitting.

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Motor is making a strange noise

When new brushes are fitted there is a period of bedding in needed, during which time (especially on first running) they can make a loud noise as the motor turns. This noise should diminish within a minute or so and diminish more after several washes.

As long as the motor isn’t sparking excessively it should be ok and they should bed in. The noise should be the same when the motor is running as when you turn the drum by hand. It is the noise of new brushes riding over the segments of the commutator on the armature which is always loudest before they bed in.

Motor making loud clicking noise?

If there is a discernible click on each revolution, then one of the copper bars on the commutator that they run on could be loose and slightly raised. In serious cases even missing. This can’t be repaired and a new armature or motor would be required.

To test for this remove the motor from the machine and place a fingertip on the commutator (the copper part with small individual sections). Slowly rotate the armature from the end where the belt fits. See if you can feel if one of more of the copper bars is slightly raised or not. If so the motor needs replacing (if it’s economically viable).

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33 thoughts on “Fitted brushes now motor sparking”

  1. Andy Trigg (Whitegoodshelp)

    Hello Steve. Most carbon brushes are designed to only fit one way. The holders are usually keyed. The main thing to bear in mind is that the curved part of the brush needs to run on the commutator which is the copper segments. If brushes are fitted the wrong way round then only the edge of the brush touches the commutator which will result in a rackety clicking sound and the distinct lack of power and sparking.

  2. since I’ve fitted new brushes the electrics on my machine are going crazy when I turn it on. what could be causing this?

    1. Andy Trigg (Whitegoodshelp)

      Excessive sparking? If it’s sparking badly then hopefully the article above covers every possibility. Otherwise it sounds a bit unexplainable.

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