Ridgid R41421 saw burning brushes

[hollywoodbusa]

I replaced the brushes for a second time because they start smoking and saw stops. Barely any pressure cutting 1 piece of 4" square tube. I guess I'm going to have to take the whole saw apart to figure out why. It spins smooth and doesn't make any grinding noises, I don't know what is causing it.

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[The Cobbler]

a short in the armature I'm thinking

 

[BFBOB]

Weak brush springs. Overheating softens them, and then insufficient pressure causes more overheating due to not enough pressure to make good contact ... and so on.
Replace them. Some brushes come as a complete assembly, brush, spring, wire and connector. If you can get it like this for yours, it's the way to go.

The most common cause in my experience - but Cobbler could be right too. A DMM that will measure small fractions of an ohm will tell the tale.

 

[darkzero]

When you replaced the brushes, did you clean the commutator at all? They get glazed. Can deglaze them with rubberized abrasive such as Cratex. They used to sell commutator cleaners for RC cars but not sure if they still do as everything has changed to brushless motors.

 

[dogdog]

carbon shorting out the two or more adjacent tracks ? I think something like that happen to my vacuum motor on the ULV sprayer...


This was the thing to do in the old days of the DC motor , generators on aircrafts... before alternator was allowed...

I end up cleaning the armature pads with a find grid sandpaper(s) on two Popsicle stick up to 400... and re-groove the gaps with a pick... been good so far. Also washed the loose carbon off... I think used a brake clean or something mild... and let dry...

Not saying it is or it is not your problem... just take a look into the armature pads and you can usually tell...

 

[hollywoodbusa]

Cool thanks for the info. I noticed also its cutting at an angle away from the saw. Could be the bearings are worn out.

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[Showkey]

a short in the armature I'm thinking

Me too.....^^^^^^^ as in excessive current draw.

 

[hollywoodbusa]

Yea id say its toast.

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[dogdog]

looks fine...

Just use a pick on the grooves dig it a bit deeper than the pads (not too crazy)

and sand down the pads with 200 then 400 grid sand paper... that looks like it's been arcing pretty good there.

Then spray down the fine dust with something like degreaser or something non-damaging to the coating. I wash it in the sink... and let dry before use.

 

[hollywoodbusa]

The sparks flying from the armature and brushes melted the brush holders, broke one brush and melted part of the plastic motor housing. Never seen anything like this. Do you know the max resistance allowed for the armature?

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[dogdog]

I don't think those resistances are universal... but if you find a pair, the others should be the same reading.

 

[bcschief]

Most likely a problem with the tool but could also be voltage drop like using it with a long undersize extension cord.

 

[RTM]

I agree with dogdog, nothing terrible there. Now that you are that far, a clean up will only take a few minutes.

 

[dogdog]

BTW OP...

Since you got a Ridgid, I would call them and check if you have a life time warranty coverage on your particular saw first... they might cover it, if you have register when purchase or something.... I was considering their table saw R4512/R4520 and saw that mention some hocus pocus life time warranty.. But I never have luck with anyone on the warranty dept to warranty anything.. so....