Convert grinder to variable speed.

[tjiscooler]

Hey I have A 1 x 30 grinder thats fixed speed. What do I have to make/ buy to be able to control the speed?

Thanks guys!

 

[unky_gumbi]

Its not going to be easy is about all I can say, you could use a rheostat, but to my understanding it would burn out your motor in the long run. I think I saw one where someone used a second motor and step pulleys to give him some speed control. I am pretty sure to get true speed control you would need to get a VFD (variable frequency drive) and a 3 phase motor, and at that point you might as well spend the extra money to step up to a 2X72 grinder.


EDIT
Found the video of the step pulley conversion, but its on a 2X42 grinder
[video=youtube;2qfYT_m2Tw0]http://www.youtube.com/watch?v=2qfYT_m2Tw0[/video]

 

[parbajtor]

Run the motor through a gearbox for single phase. Use an inverter on 3 phase.

 

[thegeek574]

depending on how much the grinder cost you in the first place, it would be worth it just to go to a 2x42 or a 2x72 becuase of the time and parts involved. I don't really understand it, but I know it is not easy and probably isn't worth doing on a 1x30.

 

[tjiscooler]

I wasnt aware a rheostat would do damage. Understood fellows! Ill just wait to upgrade eventually, thanks.

 

[xmtgx]

The only way to do it with a AC motor is a inverter to 3 phase with a 3 phase motor, or a vfd to 3 phase with a 3 phase motor. you cant control the speed on a single speed motor. Even if you could you lose 1/3 of the power output of the motor to gain variable speed. IE if you have a 1.5 hp motor setup with a VFD your only getting 1 HP out.