Poorly Angle Grinder

[rtcosic]

Hmm. A new one could be had for under £50.
A new rotor could be as little as c. £15 or over £50 depending on just which model this is.

I think a new one is called for.

 

[Kram]

Could I suggest removing the damaged loose winding or the bits accessable and then coat with epoxy. If the grinder still worked/works, this will perhaps prevent it getting worse or any more smoke but at reduced performance.

 

[rtcosic]

Could I suggest removing the damaged loose winding or the bits accessable and then coat with epoxy. If the grinder still worked/works, this will perhaps prevent it getting worse or any more smoke but at reduced performance.

This is the small low powered one and it ran at much reduced speed whilst emitting smoke.

I'll disassemble yet again and try to find model numbers inside and find out how much a new rotor is.

 

[rtcosic]

Progress.

Small grinder: cleaning and inspecting all the parts revealed a part number which led to an Amazon listing of this part being for a 9554NB.

This allowed me to search the online parts shop and find the correct rotor for £18 delivered.
Next week will reveal if I've got the right part.

Large grinder: this demonstrated why it's always best to go back to first principles. Continuity testing showed the power cable live to be broken. Given the state of the outer cover at both the plug and appliance end this is not a surprise. There must have been an intermittent or partial break and it's finally given way.
After lunch I'll go through my 'might be useful one day' box of power leads. Wish me luck!

 

[Agroshield]

...revealed a part number which led to an Amazon listing of this part being for a 9554NB.

Maybe write the model numbers of the two machines somewhere inside the casing where it will not be erased when you reassemble.

If you are going to change the power lead, consider a useful length. In general, I find grinder leads too short. Rubber (H07) cable is a lot more pleasant than PVC due to its increased flexibility.

 

[arther dailey]

My small Makita angle grinder suddenly slowed down, got warm and emitted a few wisps of smoke before I turned it off.

I've checked the brushes and the visible part of the armature which are fine. I've blown it out with compressed air. It turns easily and smoothly by hand.

I spoke to it nicely and started it but more smoke.

Are there any useful diagnostics I can do with a basic multi meter? If I do find something is it likely to be repairable? Last time I checked replacing stator or armature was not economically viable for this small single speed model.

I bought a reasonable makita years back, worked nice but soon let smoke out , discusted at wasting my monies I bought cheapest on sale at ?B Q , @ £12. still using to this day , never cleaned , never will be , just renew with next cheapo , they are nt worth wasting time on .

 

[arther dailey]

Starting with the little one:
Rotor:
View attachment 478512

Zooming in on the suspicious lack of insulation at each end:

View attachment 478513View attachment 478514

So, oh Forum Experts - is this my problem and if so what can I do about it?

Next; is this a problem?

View attachment 478515

I don't see any witness marks on the stator, nor any issues with the wiring:

View attachment 478516

thats fubar , needs replace or rewind.

 

[rtcosic]

thats fubar , needs replace or rewind.

Yup, everyone agrees, which is why I've bought a replacement.

 

[rtcosic]

Large grinder: this demonstrated why it's always best to go back to first principles. Continuity testing showed the power cable live to be broken. Given the state of the outer cover at both the plug and appliance end this is not a surprise. There must have been an intermittent or partial break and it's finally given way.
After lunch I'll go through my 'might be useful one day' box of power leads. Wish me luck!

I cut off the worst of the power lead at the grinder end but didn't reveal the broken length.
Then I cut off right at the molded on plug and had continuity.

So the faulty wire lay within the molded on plug!

It all works now, just with a power lead about 150mm shorter.

 

[rtcosic]

Update on the smaller grinder. Once I managed to identify the model I ordered a replacement rotor from:

Parts for Powertools - Power Tool Spares

Over 1 million spare parts and accessories - Power Tools spares, Lawn Mower spares from over 50 manufacturers - Black & Decker spares, Bosch spares, DeWalt spares, Dremel spares and much more.

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For £18.39 delivered.

I finally got around to fitting it tonight. It was a simple job that went without any drama.
I now have all my grinders in full working order.