1.75 hp D.C. Motor for SB 9??

i disagree my dc treadmill motor will not stall but the poly v belt will slip (1 3/4 hp motor
 
I was thinking of doing that with my enco mill , it's 1HP and under powered in my book. I don't think it would be to much power for the 9" lathe . My worry is do they run hot and need more cooling then a.c. motors. As a kid who's burnt out dc motors it's a factor in my brain.
 
Thanks all, for your replies. The price for motor and controller, plug and play is $200. This particular motor is the only one the guy has, apparently. I see Grizzly now charges $150 plus tax and shipping on their high end 1/2 hp fully enclosed machine tool motor. So not much difference in my cost. More for 3/4 hp and 1hp.

I plan to mount a motor on the standard SB countershaft motor mount assembly and run an automotive serpentine belt between the cone pulleys. Maybe leave it set up on an optimal speed range on the pulley and use variable speed control when necessary. This works fine on my 7" x 36 Dalton lathe - using the same style SB countershaft assembly.

Also suppose I could scratch around eBay or CL and save 50 bucks for a used motor. But, getting tired of making do with old used equipment - partixularily electric motors that let the magic smoke out soon after landing in my shop.

Think I will explore this D.C. Motor thing a bit more - confirm max RPM limit, variable speed control, etc. if a nice, cheap 1/2 or 3/4 horse AC shows up locally in the next few days, then D.C. would be moot.

Glenn
 
you will be sorry for not going with the 1.75 hp dc, i have done 2 lathes with this setup, and no problems. The first was a atlas 10", which i sold , now i own a 9" wide bed south bend. The first 1 i used the treadmill controller and it worked great, this one i'am using a danfoss 2000, really no difference. Be sure to use the fan, they will run hot on the slow speed, and keep the counter shaft setup. I also have my band saw dc powered running off the same controller.

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Kernnigo, What fan do you speak,of? Is there a an internal fan, or should I add one? If so, how big and where is it placed etc?

I emailed the seller and am likely going to pick it up a few days. He will put an internal limit switch inside the controller to limit the max rpm to 1750. (The motor is rated at 6000 RPM! I don't want that speed ever to kick in around this lathe). Plus an external control to adjust speed during operation, plus a digital tach. If the digital tach is a workable solution, I think I will put one on my old 1919 Dalton Lathe, and another on my 21" camelback drill press. The DP needs a motor installed, but has power down feed on the quill. Iam thinking it will be useful to tweak speeds on this big machine, if the downfeed still proves workable.

The SB guys in 1925 that made this particular lathe would never have imagined how it would be powered and tweaked whilst turning work a hundred years in the future!

Thanks very much for your comments and encouragement to move ahead with the DC setup.

Glenn
 
yes you need a external fan, running slow rpm it will over heat and kick out thermal overloads

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He will put an internal limit switch inside the controller to limit the max rpm to 1750. (The motor is rated at 6000 RPM!
Sounds a little slow to me. I would think you would want it to be capable of approx 3000rpm so you can slow it, and speed it up without changing it. if you limit to 1750 you cannot take advantage of your higher speeds since you will have to adjust the belt.
Tonight I used the highest speed cones while in back gear. I needed to take some big honking cuts but wanted to get it done as quickly as I could. So I went to back gear and fast for torque and speed.

you may not need the 3000, but 1750 is too slow...
 
Glenn is this a treadmill setup the guy is selling or something else? Have you any pictures?
Mark
 
i believe your 9" south bend spindle is only rated 1000-1200 rpms max, you will burn it up any higher
 
i believe your 9" south bend spindle is only rated 1000-1200 rpms max, you will burn it up any higher

But we are not talking the spindle speed, he is still using the motor drive unit with reduction already built in.
 
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