Motor sparking after new armature and brushes installed

[_fly_]

A friend has 2 dewalt table saws, both machines had armature problems after long continuous use.
I checked the fields and both seemed OK, so he ordered new armatures and brushes for both.

All put back together and one sparks a little the other sparks a lot (so he tells me).

Now I know they will need a little while to bed in properly (a minute or 2).
I'm not sure how long he's run them for yet.
I'll check the brushes are installed right and the springs are doing their job properly and keeping contact.

Anybody got any other ideas I should check for?

Pete

[Yanis]

Is the sparking coming from the brushes? If any of the wires came adrift inside they may be rubbing and worn through. The brushes may spark a very small amount, not a lot. Yes, check that the spring tension is OK, they may be stuck.

John

[_fly_]

Well Luckily enough he had burnt out the field on 1 machine before I got there.

The second machine is sparking still from the brushes. Will get up to white hot in 5 seconds, the brushes are nice and warm at that stage.

Same things with the old worn in brushes.

I told him that a short yellow park every couple of sec is ok, but white hot at the brushes is not good.

Not sure whats going on, New armature, new brush holders, new brushes. Only thing old is the field that was ok (no longer available new or that would have swapped as well)

He's going to turn on for 2 secs, leave for 2 minutes and repeat, about 30 times and see if brushes need to bed in better.
It comes up to proper speed and he says it sounds ok.

Armature spins freely, RPM on blade seems ok, no seized bearings.
After that not sure what could be.

Anyone know where he can get the dead field rewound?

Peter

[A Duke]

Hi,
Are the new armatures for the correct voltage, or has some one supplied spares foe a 115V unit?
Just a thought.
Re3gards

[_fly_]

Oh, now that may be possible.
He ordered from ereplacementparts.

That sounds like the issue I guess.
I better check what he got.

[_fly_]

Yep, sure enough thats what he ordered as they only listed one type.
He needs the 153527-03sv version and not the 153527-00sv which is what they sent.

Now to find him an aussie supplier or UK supplier of the part.

[Yanis]

I have used these guys http://www.toolspareparts.com.au
(http://www.toolspareparts.com.au/power-tools.html?manufacturer=16)