Went to make some spacers to install a digital readout on my table saw, turned the mill on and it made a bad noise for about 30 seconds then stopped. Breaker tripped. Reset the breaker and the same thing happened. As I was checking things out I noticed one of the starting capacitors was very hot. Looking closer there was smoke coming out of the cover over the starting capacitor. After taking the cover off I found oil inside the cover. Obviously dead capacitor. Decided it's time to make the switch to the VFD and ordered a motor off of eBAY. But in the meantime decided to replace the capacitor and ordered one from McMaster. But today talking to one of the electrical engineers at work he said to check the centrifugal switch which is supposed to cut the capacitor out after the motor gets up to speed. Anyone ever have something like this happen?
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Let the smoke out
- Thread starter DeanB
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Yes. I have a motor that does it on occasion. Loud grinding / growling noise as soon as you power it on. If you get to it fast enough it doesn’t trip the breaker, if not, smoke usually happens. There are solid state retrofits that can be done but it sounds like you have a new motor on the way anyway. There was a good post a few weeks ago here...
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Single Phase Motor Problem
The 3hp single phase AC motor on my lathe has developed an issue that I am having trouble finding a match for online. When I start the lathe, the motor will turn, but it buzzes or vibrates significantly and if left on for more than a few seconds, it trips the breaker. The odd thing is that it...
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Yes I did, by the time the motor started to smoke it was toast. At least the capacitor was. I just replaced the motor. I may have been able to save it by replacing parts, but replacing it was far better as I replaced with a better motor. This was on a drill press and I replaced it with a DC variable speed motor from an industrial sewing machine. Man that thing had so much torque, you had to be very careful.
But I got side tracked, The answer was yes.
But I got side tracked, The answer was yes.
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- Jan 10, 2019
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To the OP, did the motor run in those 30 seconds? If so, then yes, it's the switch and it'll do it again unless you fix the switch. Until you get the new motor you can disconnect the starter cap, tie off the wires, and start the mill by giving the spindle a spin by hand, if need be.
It is ALIVE again! Finally took the time to install the new 3 phase motor and drive. Works fine but my eBAY motor has a squeal in the shaft end bearing. On the plus side I contacted the seller and had a full refund within about 10 minutes. New motor on the way. A little programming to do on the drive yet but it does work and seems to hold speed very well.