# variable speed controller , rheostat for leeson 110/220v motor



## tmatt4 (Dec 27, 2013)

Hi I have a leeson 110/220v motor and I need to drop the speed on the motor can I use a  KBWC-210K to do or is there anyother recomendations without use of a vfd. The leeson motor runs at 3450rpm and my old motor runs at 1750rpm.


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## John Hasler (Dec 27, 2013)

tmatt4 said:


> Hi I have a leeson 110/220v motor and I need to drop the speed on the motor can I use a  KBWC-210K to do or is there anyother recomendations without use of a vfd. The leeson motor runs at 3450rpm and my old motor runs at 1750rpm.



While the manufacturer says that you can use that device with induction motors (and you can, sort of, in some applications) it won't work at all well with a motor driving a machine tool.  Change the pulley.


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## tmatt4 (Dec 27, 2013)

John Hasler said:


> While the manufacturer says that you can use that device with induction motors (and you can, sort of, in some applications) it won't work at all well with a motor driving a machine tool. Change the pulley.



is it due to the lower amperage at slower speeds? I am trying to lower speed for my clausing lathe. I am new to this..the lathe does have different positions for belts maybe it will be slow it down enough. I and using lathe to mahcine aluminum compressor housings.


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## CluelessNewB (Dec 27, 2013)

I assume the Leeson is a typical capacitor start motor.  If that is true you really don't have any viable option for reducing the speed of the motor itself.  If you can use a smaller pulley on the motor and/or a larger pulley on the device that would work.  Capacitor start and split phase motors have starting winding and a centrifugal switch that disconnects the starting winding when the motor gets up to speed.  If the motor doesn't get up to speed and the starting winding is not disconnected the motor will overheat.  These motors usually also have an internal cooling fan on the shaft that depends on the speed to keep the motor cool.

- - - Updated - - -

From this page:

http://www.kbelectronics.com/kbsearch/descriptions/popup_kbwc_210ka.htm



> The KBWC-210K provides infinitely variable speed motor control for Shaded Pole, Permanent Split Capacitor and Universal (AC/DC) motors.



Your motor is probably a capacitor start motor not any of the types listed above.  None of the motor types listed have a starting winding.


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## John Hasler (Dec 27, 2013)

tmatt4 said:


> is it due to the lower amperage at slower speeds? I am trying to lower speed for my clausing lathe. I am new to this..the lathe does have different positions for belts maybe it will be slow it down enough. I and using lathe to mahcine aluminum compressor housings.



It is due to the fact that induction motors are designed to run just a bit slower than synchronous speed.  That is determined by the line frequency.  VFDs change the speed of induction motors by changing the line frequency.


Replace the pulley on the motor with one half the diameter of the present one.


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## tmatt4 (Dec 28, 2013)

John Hasler said:


> It is due to the fact that induction motors are designed to run just a bit slower than synchronous speed. That is determined by the line frequency. VFDs change the speed of induction motors by changing the line frequency.
> 
> 
> Replace the pulley on the motor with one half the diameter of the present one.



the current pulley is prob about 2" in diameter, I have not installed motor yet but will tonight to see how it does, thank you for all the help


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## Hawkeye (Dec 28, 2013)

You may indeed be able to get your lathe slow enough for aluminum by using the speed-change pulleys. I'd advise some form of tachometer, such as a laser tach, to check actual speeds. If you go this route, please don't try to cut steel until you confirm that you can set the proper speed for the material, tool type and diameter.

Long term, the proper motor will allow you to get the most out of your lathe.


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