New mitre saw sparking at motor when I release the trigger

[sensi5446]

Hi,

I bought a new sliding mitre saw on Friday and made a few things with it yesterday out of old wood in the garden, I was really just trying it out I had it set up outside screwed to my workmate and all has been fine.

This morning I used it again but as its raining I'm using it in my shed, I have lighting in the shed but its a bit dull in there, I noticed that when I let go of the trigger I get a flash or spark from the motor housing, can someone with more experiences with this type of tool tell me if this is normal or not?

Thanks

[Yorkshire Geek]

If it has an electric brake it might be normal, if not then that doesn't sound ideal to me.

[sensi5446]

[Yorkshire Geek]

If it stops quickly that sounds a fair bet then - mine takes a good 10 seconds to wind down but doesn't spark.

[MCN]

It should not spark. What if a spark ignited cuttings?

Sounds like the brake has something foreign between the friction parts what the brake is meant to rub against.

Maybe some sand or grit got in through the motor air grill.

And you know the drill on here.

Make and model.


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Disclaimer: The comments above may be predicted text and not necessarily the opinion of MCN.

[Polarbear]

Is it sparking at the commutator?

Is it a brushless motor or does it have brushes?

If it has brushes you will almost certainly get some sort of sparking.
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[fatjames]

My cordless drill does this, but I only ever notice if I'm drilling in the dark.

[grr666]

A bunch of my powertools do this. Never been an issue.
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[sensi5446]

[MCN]

I saw a clip of this saw. The motor has carbon brushes.
It still shoukd not spark.
It is not safe for an explosive environment but there should not be any sparks coming out the motor.

The sparks are from 'something' disintegrating at the commutator/carbon brush contact face.
You could pull the brush out of each side and see what the surface looks like.
It should be curved but polished smooth.
If something is eating the brush it will be gouged and rough.
If so, ask for a replacement saw.
If the brushes are damaged then the commutator will be damaged too.

It may well be that dust or other shit has dropped in through the motor vents in the factory, store or at your gaff.

I would look at the brushes and take it from there.

Broken brushes due to a damaged commutator will not last. And replacements will suffer a similar fate.

https://en.m.wikipedia.org/wiki/Commutator_(electric)

The commutator may be repairable too. But it will require access to the end of the motor and special tools and some knowledge.
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Disclaimer: The comments above may be predicted text and not necessarily the opinion of MCN.

[sickpup]

[MCN]

[Polarbear]

It depends what he is calling 'sparking'

All brush motors spark a bit at the commutator, you just don't notice it until you run them in a dark place.

Either take it back to the shop you got it from and get it replaced (I doubt if they will even check it if iot is a major retailer) or ignore it if it is causing you no problems.

https://www.youtube.com/watch?v=LQ39YL7L2WQ
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Triumph Trophy Launch Edition

[MCN]

Using power tools in the dark now?

Ah.. you were fitting a light. 😂

Yes brush motors spark.
Bit the sparks should not be visible in 'normal' conditions.

On a new motor it would be a cause of further investigation.

The brushes on that motor are simple to remove for a shoofti. (even using penny in the dark if that is one's bent. )
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Disclaimer: The comments above may be predicted text and not necessarily the opinion of MCN.

[sickpup]