Electric Motor Dialing down speed?
 

1) I have an electric motor, I think it's 1/2 horse, that runs my Band Saw.
Right now it has two sets of pulleys so that I can either change the belt to
fast or slow. I'm wondering if it's possible to add a switch to the power
supply so that I can dial in the speed of the motor? Is it possible to use a
light dimmer switch or will I just kill the motor. Any ideas? I change up
between sheet metal and wood a lot and it would be a lot easier to just dial
down the speed for the 2 minutes I'm cutting the sheet metal.

On 2005-04-15, HotRod wrote:
1) I have an electric motor, I think it's 1/2 horse, that runs my Band Saw.
Right now it has two sets of pulleys so that I can either change the belt to
fast or slow. I'm wondering if it's possible to add a switch to the power
supply so that I can dial in the speed of the motor? Is it possible to use a
light dimmer switch or will I just kill the motor. Any ideas? I change up
between sheet metal and wood a lot and it would be a lot easier to just dial
down the speed for the 2 minutes I'm cutting the sheet metal.

You'll kill the dimmer first, then the motor.

If you want speed control, go to eBay and buy a three phase replacement motor
and a three phase speed control for it. Be sure the three phase controller has
single phase input.

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HotRod wrote:
1) I have an electric motor, I think it's 1/2 horse, that runs my Band Saw.
Right now it has two sets of pulleys so that I can either change the belt to
fast or slow. I'm wondering if it's possible to add a switch to the power
supply so that I can dial in the speed of the motor? Is it possible to use a
light dimmer switch or will I just kill the motor. Any ideas? I change up
between sheet metal and wood a lot and it would be a lot easier to just dial
down the speed for the 2 minutes I'm cutting the sheet metal.


It won't hurt the motor but it will probably burn up a light dimmer
switch. Try to find something heartier.

HotRod wrote:
1) I have an electric motor, I think it's 1/2 horse, that runs my
Band Saw.

Assuming it's a standard AC induction motor (it will probably say so on it),
it's speed is set by the line frequency, not voltage. A dimmer would not
help you.

You can do as another poster suggested and replace it with a 3 phase motor
with a variable speed drive, or possibly cheaper would be a 2 speed motor
(1800 and 3600 rpm).

For these prices though, it might be cheapest to simply get a second band
saw!

"Assuming it's a standard AC induction motor (it will probably say so
on it),
it's speed is set by the line frequency, not voltage. A dimmer would
not
help you. "

That's correct. Not only will it not help you but it will burn out the
dimmer since std ones don't have the current capacity nor are they
built to deal with inductive loads. And if you find one that can
supply enough current, it will burn out the motor.

Sounds like my options are to buy another saw or another motor.....

Another saw takes up to much room and another motor costs more money, saves
space but I still have to change the blade all of the time. GREAT another
decision to make. Thats why I came here to have you guys think for me while
I sit on the deck and have a drink. THANKS...

HotRod wrote:
1) I have an electric motor, I think it's 1/2 horse, that runs my Band Saw.
Right now it has two sets of pulleys so that I can either change the belt to
fast or slow. I'm wondering if it's possible to add a switch to the power
supply so that I can dial in the speed of the motor? Is it possible to use a
light dimmer switch or will I just kill the motor. Any ideas? I change up
between sheet metal and wood a lot and it would be a lot easier to just dial
down the speed for the 2 minutes I'm cutting the sheet metal.


It won't hurt the motor but it will probably burn up a light dimmer
switch. Try to find something heartier.

I got a dimmer switch that will work:
Cast Iron, weighs about 12 pounds. Rated for 860 wats.
But you gotta be willing to pay antique rates, and shipping.

Rebuilding the transmission so you can move the belt easily will
be cheaper.

Or steal the foot-pedal from someone's sewing machine.

I got a dimmer switch that will work:
Cast Iron, weighs about 12 pounds. Rated for 860 wats.
But you gotta be willing to pay antique rates, and shipping.

Unless it's an antique frequency drive, it's not going to work either.

Rebuilding the transmission so you can move the belt easily will
be cheaper.

Or steal the foot-pedal from someone's sewing machine.

Which would only work if it had a brush type "universal" motor - which is
highly unlikely.