Speed control for a Myford Lathe.

[decca]

I am thinking of adding a variable speed control to my Lathe. It's a ml7. Will I be able to use something like this:

http://www.ebay.co.uk/bhp/ac-motor-speed-controller

Or is it not that simple?

Thanks for any suggestions.

 

[Pete.]

No, that won't work. The speed of an AC induction motor is determined by the frequency. That speed controller will only work on a brushed motor AFAIK.

 

[decca]

No, that won't work. The speed of an AC induction motor is determined by the frequency. That speed controller will only work on a brushed motor AFAIK.

Ok, Thanks for the help.

 

[rikrobson]

you will need a 3 phase motor and a vfd to give variable speed.
the type of board you have there will simply limit the voltage on the sine wave making the crests and troughs flatten to the lower voltage. As Pete said the speed is dependant on the frequency of the supply. here its 50Hz. with a 2 pole motor this will give a 3000 RPM native speed. Induction motors have an inherent "slip" in the rotors field, which is why the RPM for a motor is usualy about 2850 RPM. these are halvedd for a 4 pole motor. (1500 and 1425)

therefore if you drop the voltage too much the motor will stall.

 

[decca]

you will need a 3 phase motor and a vfd to give variable speed.
the type of board you have there will simply limit the voltage on the sine wave making the crests and troughs flatten to the lower voltage. As Pete said the speed is dependant on the frequency of the supply. here its 50Hz. with a 2 pole motor this will give a 3000 RPM native speed. Induction motors have an inherent "slip" in the rotors field, which is why the RPM for a motor is usualy about 2850 RPM. these are halvedd for a 4 pole motor. (1500 and 1425)

therefore if you drop the voltage too much the motor will stall.

Thanks for that. It looks like its a non starter then.
Never mind I just get these ideas sometimes.