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Old 08-04-2014, 01:15 PM
Angel Angel is offline
I miss my MBZ
 
Join Date: Feb 2003
Location: Cincinnati, OH
Posts: 563
My most-likely hypothetical is this:
WHen the switch welded shut, it did so in a high-resistance manner (example: a bunch of current was being spent making heat in the switch so less was available downstream) dropping a lot of voltage through it and giving the motor lower-than normal voltage at the motor leads.
Lower than normal voltage on motors like yours (example: 80v on a 120v motor) will still run the motor, but it'll make less power, drop speed quicker and demand more current than normal (most 120VAC motors are 'tuned' to run efficiently at 120v, give them less and they act as described above).
Your low-voltage motor run circuit was so far off that the motor amps were up, high enough to heat the motor internals/insulation/metal plating and turn it to white smoke- which you saw.

Somewhere on the internet, are bottles of "magic smoke", normally with the manufacturer "Lucas", of British Sports car fame

Back in the real world - if you dont have a spare radial saw- I'd go ahead, power it back up (from a safe distance) it might work fine, it might not start, it might run slowly and smoke again. if it doesnt run well then the motor is probably permanently damaged, and you'll either need a new motor or a new saw. (if its a sears model- check searspartsdirect.com - they have a LOT of parts on there....) motors on these things are not difficult for a handyperson to replace.

Post up the manuf. and model number of the saw and maybe get more information from us

Lots of EE's on this board, I welcome corrections and feedback (I now work a lot farther from the power plant than I used to...)

-John
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