Ken Kelley Posted April 2, 2008 Share Posted April 2, 2008 I am researching motors to use for a low-speed horizontal disc grinder. I'm an electrical dummy so I'm fair lost in the weeds in this subject area. However, I do understand dimly that DC motors are best for applications requiring torque over speed and found this motor on Ebay 150231105735. It appears to be what I need but before I plunk down $49 + $12.50 shipping charges I would like to know what those of you with electrical experience think of this machine. Thanks, Ken Quote Link to comment Share on other sites More sharing options...
Ice Czar Posted April 3, 2008 Share Posted April 3, 2008 while Im not all that great at this game, I think youll need something more than a 12V DC motor for a grinder linkElectric Gear Motor 12v Low Speed 50 RPM Gearmotor DC - eBay (item 150231105735 end time Apr-05-08 13:14:21 PDT) Quote Link to comment Share on other sites More sharing options...
Mills Posted April 3, 2008 Share Posted April 3, 2008 If you elaborate on your application you may get a better response. I have no experience with DC but My Drill press has a lot of torque on the bottom end through gearing and it works nicely. DC may be a better choice for speed control. Quote Link to comment Share on other sites More sharing options...
Don A Posted April 3, 2008 Share Posted April 3, 2008 What is the normal horsepower rating on a treadmill motor? I assume that those are DC because of their speed controls. I only ask because I have access to one that is headed for the dump and the motor is still good. I see a lot of them being thrown out from time to time. They would be a good resource for scrounged motors if they have what it takes. Don Quote Link to comment Share on other sites More sharing options...
Mills Posted April 3, 2008 Share Posted April 3, 2008 Don there are several folks around who have successfully used the treadmill components. Usually as a belt grinder w speed control. I think that it is best to keep the wiring harness and all, for that is already ready to go. Don't treat it like a washer or dryer and simply snag the motor and trash the rest. Quote Link to comment Share on other sites More sharing options...
Ken Kelley Posted April 4, 2008 Author Share Posted April 4, 2008 Thanks for you input everyone. However, since I first asked this question my electric motor education has increased by leaps and bounds through contact with a feller on Blade Forums and some judicious wandering around the internet. I found a forum site called the Practical Machinist. One of the subforums addresses the variable speed motor issue in detail. It seems that the best way to go for a variable speed set up is to run a 3 phase motor using a Variable Frequency Device. The VFD is a bit on the pricey side but the motors are relatively cheap. Too much detail to go into here but the VFD/3 phase motor combo definitely seems to be the way to go for my grinder purposes as opposed to the DC idea. Ken Quote Link to comment Share on other sites More sharing options...
Ice Czar Posted April 5, 2008 Share Posted April 5, 2008 assuming that 3 phase is available, because phase converters are also pricey If your going to employ a Variable Frequency Drive Id highly suggest you provide it a nice cool dust free home, At the shop when ours finally fried, it wasnt replaced. ($700)3 Phase Inverters Home Made 3 Phase (disclaimer: Have no idea how well this may work) Quote Link to comment Share on other sites More sharing options...
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