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Can anyone help me I need to slow down a 120v radial arm saw. It is an older model with 6 brushes. The saw runs at 5500rpm and I need to go under 5000rpm.
As long as its a brushed motor you can use the cheaper versions of speed controls out there. Harbor Freight has one that I believe will handle 15-20 amps. You didn't mention the amps that your motor draws, should be on the same plate as the 120V info. Whats nice in this situation is you only need to drop a small amount of RPM's. The more speed you have to drop the more torque you will loose with this type controler so I believe in this case you will be OK. The controller should be in the $20 category. Just check to make sure you are in the right amperage range of the controller. Kurt.
There is no name plate on the motor itself. The unit is just plugged into a 120v circuit which is protected by a 20amp breaker. I did see a controller on e-bay for 16.95 the looked like it would fit the bill. It mentioned a 20amp capacity as well. Since this is a radial arm saw the motor is a intregal part of the saw and can't be replaced. We are attempting to use an abrasive wheel on the saw after our 10" saw died today. Found a 12" old Dewalt saw and thought it would be perfect but wasn't thinking the max rpm for a 12" abrasive wheel is lower then for the 10" we had. Also the new saw has a 1" arbor whereas the old 10" had a 5/8" so we can't just put a 10" wheel on the 12" saw.
Well, you certainly have a dilema there. Its very important that you don't go over the recommended speed. You don't want a wheel comming apart at 5K rpm! I suppose if you have a tachometer you would be sure. Aside from that it would be a crap shoot and not too safe. Good luck, but stay safe!
I do have a tach. It was fresh out of my frozen truck and the display wasn't working very well probably do to frozen batteries but it appeared to be going 5500rpm. I will retest Friday and figure out what to do.
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