240v 1ph 1600W Table saw motor wiring question

[Steve Blackdog]

Update:

I stripped everything down again and put it back together, but this time with the brush holders clear of the commutator.

I can see now that the brush holder fouling the armature was the root of the problem, as with the brush holders back (with new brushes), the armature spins freely and much more smoothly. However, I'm not sure whether this has done irreparable damage to the motor.

I switched it on and hey presto... the motor turned.

2 issues though,

a) it was very slow, seemed to slow; and
b) smoke started to come out of the motor.

The fuse no longer blows. I ran it for maybe ten seconds or so.

When I opened it up, I couldn't see the source of the smoking. The armature was pretty cold and the field was warm to the touch.

The fine wire in the field was burnt out when I got the motor, I soldered it up again and I don't think it is shorting, but I guess it could be somewhere inside the coils.

What do I do next?

Cheers

Steve

 

[Lucien Nunes]

Probably bin it. When a coil has blown open at an exposed point, it is likely that the inner turns of the coil that cannot dissipate heat as easily will have damaged insulation between turns. In an AC motor, even if only a small percentage of the coils short together, transformer action induces heavy current in them, resulting in overheating and general failure. This is probably why the field was hot when the armature was cold. It's difficult to prove that without test equipment, and the cost and time involved out of proportion to replacement.

 

[Steve Blackdog]

Thanks for the advice. In the bin it goes!

 

[Steve Blackdog]

Final update:

Lucien may like to know that I followed his advice and bought a replacement motor. All's well that ends.

Thanks again for the help guys.