I have a 15 year old grizzly bandsaw with a 3/4hp 1720 RPM single phase 110/220v motor. The motor is being run on 110v. Several years ago it stopped starting without help (spinning by hand) but does seem to run fine once it is going.
I finally decided to fix it. I removed the old start capacitor (150MFD, 125v) and got a new one from Grainger (145-175MFD, 110-125v). I installed the new one and the saw started right up but within a few seconds I smelled the cap. I opened it up and there was oil in the box. I ran it with it opened and it was shooting smoke and some oil out the top edge of the cap. The cap also gets very hot - too hot to hold very long.
I pulled the motor and checked the capacitor cut out switch and it seems fine. With the motor off the contacts touch and make a good connection. When the motor gets to a few hundred rpm the weights spin out and open the contacts. I can hear the switch clicking into place as the motor slows after being shut off. I took it a part and cleaned the points just to make sure - they look good.
I did blow out all the dust (not too bad), and I pulled all wires out the back to check for breaks and they all look good.
Could I have gotten a bad capacitor or do I have another problem?
BTW: with the motor running at full speed (and no capacitor in place) one of the cap leads reads about 45v and the other reads 130v. Should these have any voltage on them at full speed?
Thanks,
John
I finally decided to fix it. I removed the old start capacitor (150MFD, 125v) and got a new one from Grainger (145-175MFD, 110-125v). I installed the new one and the saw started right up but within a few seconds I smelled the cap. I opened it up and there was oil in the box. I ran it with it opened and it was shooting smoke and some oil out the top edge of the cap. The cap also gets very hot - too hot to hold very long.
I pulled the motor and checked the capacitor cut out switch and it seems fine. With the motor off the contacts touch and make a good connection. When the motor gets to a few hundred rpm the weights spin out and open the contacts. I can hear the switch clicking into place as the motor slows after being shut off. I took it a part and cleaned the points just to make sure - they look good.
I did blow out all the dust (not too bad), and I pulled all wires out the back to check for breaks and they all look good.
Could I have gotten a bad capacitor or do I have another problem?
BTW: with the motor running at full speed (and no capacitor in place) one of the cap leads reads about 45v and the other reads 130v. Should these have any voltage on them at full speed?
Thanks,
John