motors again.

Joined
Feb 11, 2003
Messages
14
I've been researching past posts to try to figure out what kind of motor to get for my Coote, but I can't figure out why everybody is going with the DC motors. A friend told me it was probably so you can vary the speed, but why is that so good? I only have 110VAC in my surburban garage--is it even possible to run 220, just so I can convert again to 120DC (I have no idea what I just said)? Why is the DC motor worth all this trouble? Will a simple AC motor be alright until I have a real shop someday?
 
An AC motor works fine. Just get the step pulleys, so you can change speeds. The thing is, with pulleys, you have to stop what you are doing to do this. With a DC motor, and control, you simply turn a dial to vary the speeds, from crawling, to very fast, and anything in between.
Variable speed can get expensive, so you want to make sure first. I hesitate to recommend treadmill motors, as their listed horsepower is really, really optimistic. I have seen 11/2-2 HP models that are smaller tham any grinder motor I have ever seen.:eek:
You can have a 220V line run from your electrical panel, to the shop. Most electricians would do that easily. ;)
 
Coty,

I've no doubt that Mike is right. A real DC motor is probably the best - if you have the $$. Personally, I've hooked up a treadmill motor/FB Electronics Controller.

The whole setup was < $225. RLinger shopped around on ebay and got a controller for < $100 - his total was more like $150.

I don't know how long it will last but so far so good (I added a fan off an alternator for cooling - works fine and creates quite a breeze :eek: ). Enough power? I can't slow the thing down. Don't know if it is a real 2hp, but it is enough.

A pulley + AC motor setup would be about the same or less than what I paid. Probably more reliable too. However, I don't like moving belts. I like turning the little knob to tune it for what I'm doing at the moment. A variable speed setup will just spoil you that's all.

As far as why variable? For flat out stock removal crank it up. Then for finer belts you can slow down. You'd be suprised how fast you can burn a tip with a 400 grit belt at full speed (well I was anyway). I've started sharpening on the grinder too. Slow speed is just the ticket. I never could do it at 3000 sfpm.


Steve
 
My total was $119 for 2 HP motor and Regenerative DC Drive. The motor came used (the same Leeson motor Itrade has) and the DC Drive came new in factory box. It all runs from the 115 V AC house outlet.

A good AC motor with step pulleys will work fine for you, of course. I like the idea of getting that RPM way down for fine grit belts for that final finish grind. Although, I haven't had a chance yet to try that.

Roger
 
I'm with these guys above, have recently set up with the same motor and an eBay controller. I have variable drive on my main grinder too, would never ever go back to one speed. Fine grit belts last much longer at slow speed, and one big difference many people overlook is the learning curve for grinding is much easier when you have the belt slowed way down. There is no way I'd ever go back to one speed - my original single speed grinder is now used for sharpening pencils and not much else...

Dave
 
Coty, some of the equipment in my shop I built using used motors. The one thing I learned quickly was to shop for closed motors. My old open end motors didn't last long because of dust; they fried pretty quick.I would use variable speed motors if I had them, which unfortunately I don't.
 
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