BeverFever Posted July 1, 2015 Posted July 1, 2015 I am an HV/AC technician and I have easy access to 1075RPM and 825RPm, 240V motors. Could I make a ball mill with these motors, or are they far too fast? I'm not an expert on electrical motors, but could I underpower or use another method to slow them down some? I know that most of you have made your own ball mills out of used motors, so hopefully you will know more than I. I would probably use a closed condenser motor over an open motor.
marks265 Posted July 1, 2015 Posted July 1, 2015 Is it a single phase or 3 phase motor. General usage motors are usually 1765 rpm so with yours running a little slower you would have to account for this in your pulley arrangement. A TEFC (totally enclosed fan cooled) is always best.
Arthur Posted July 1, 2015 Posted July 1, 2015 There are suggestions for optimal drum RPM based on diameter, but 60 - 90 RPM is often a fair guess. Take advice (there's lots here!) on the RPM for your drum after specifying the drum bore and the ball size. Remember that the motor to powered roller is one speed reduction and the roller to drum is another reduction. Maybe you will not want much reduction each time.
marks265 Posted July 1, 2015 Posted July 1, 2015 Single phase motors are easy enough to wire up as long as you have a place to plug your mill in for 240V. Because of the slower speeds you may want to watch your current load. You won't be gearing down as much as the faster motors and it may work a little harder depending on the application. I still think you would be more than fine though. Once again, it s about what you have access to. I personally use a freq drive that powers up with 120V and use a 3 phase 480v motor. The freq drive gives great control for speed control. I hate DC motors because of the brushes (for pyro reasons). DC gives good speed control as well, but sparking brushes don't thrill me. Anyway I have a 2K Honda generator and plug my mill into a 120V outlet and I'm in business.....for a full day in the pit. It's hard on the back but great on the powder buckets!
Blackthumb Posted July 2, 2015 Posted July 2, 2015 Find an old treadmill. Usually a variable speed dc motor with the controller board....taking one apart now for star roller.
Arthur Posted July 2, 2015 Posted July 2, 2015 For pyro use I'd be keen to get low sparking motors, certainly NOT brush motors. Induction or synchronous motors are best. I'd also use a motor at it's intended speed so that any cooling is up to standard -even fit a fan! Motors on speed controllers may not have good cooling at all speeds.
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