# Slowing a motor speed



## don-tucker (Dec 13, 2009)

I have this bandsaw that runs to fast for metal,so I wondered if there was a way to slow the motor down electrically,I didn't fancy gears or pulleys as I thought it would be a bit untidy,but I haven't ruled them out.I wondered if there was something on the market somewhere.
Don


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## John Rudd (Dec 13, 2009)

Don,

The 'how to do it' depends on the type of motor fitted to your saw...

It can be done using a variable frequency drive unit to alter the speed by changing the frequency of the supply to the motor..

If you do a Google on 1 ph motor speed control, there's various resources on this.....


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## websterz (Dec 13, 2009)

Slowing a motor electrically will often result in a loss of torque. Mechanical reduction using gears or pulleys/jackshafts doesn't.


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## Stan (Dec 13, 2009)

Slowing down a motor the amount required for what you want is usually not satisfactory. If you want to avoid open belts and gears consider a gear motor. There are lots of these available on ebay and the the various surplus places that are on line.


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## Kermit (Dec 13, 2009)

Motor speed controls work great for DC motors, but not so well on AC single phase motors.

Check the ID plate on the motor to see if it is 3500-3600 RPM or if it is 1600-1800 RPM/ If the motor is marked for the higher RPM you could replace it with the slower running type of AC motor. Both are very common.

Electronic methods of slowing the motor always cause a reduction in power as well with these motors.

Belts and pulleys are the BEST way. A DC motor with variable speed is the other option.

One other thought, Are the pulleys the three step type?  You could turn one pulley upside down on its shaft(maybe) and use a smaller belt to connect the motor and get a slower speed that way?

Kermit


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## don-tucker (Dec 13, 2009)

Thank you all again,I will have to to have another look at pulleys I think or the geared motor option.
Don


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## Dunc (Dec 18, 2009)

There are several speed reduction ideas in old Pop Sci & Mech magazines. A compact one is found in the Feb 1969 issue.


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## Alan J. Richer (Dec 21, 2009)

I did exactly this with an old King-Seeley bandsaw. Wood saw, perfect for that in direct drive, but useless for metal.

I ended up putting a gearbox (30:1 comes to mind - I bought it surplus) onto the motor, remounting the motor and gearbox combo so the gearbox output shaft was aligned with the saw's input. A set of pulleys of 1:1 ratio finished it up, giving a nice slow speed for metal cutting. 

Still works fine for wood as well, but it's not terribly fast at it...

   Alan


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## don-tucker (Dec 21, 2009)

I shall have a go when the weather warms up a bit,all useful info.Thanks
Don


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