VS treadmill motor setup

[TomServo]

I started a new thread for this instead of continuing to hijack the jet mini VS thread - I bought a treadmill motor from surplus center and the 8 amp controller. Today I had a chance to install it with my Taig lathe... pictures ensue..

One note - I am not done installing it - i'm going to use some 1/4" plywood to enclose the motor and provide somewhere to mount a small fan. The motor came with a heavy cast steel flywheel with a fan built in but i decided it was simply too dangerous to use this way..

On to the testing! I tossed an ebony blank on my mandrel and turned it round - the motor runs great! the torque with the motor spinning below ~250 RPM is a bit wimpy, but we're talking a spindle speed of about 90 RPM. I wish I had some way to measure the spindle speed accurately. Something to note, in my setup I spin the motor CCW (it's a CW motor), which should not be a problem with DC motors, but to get it to start spinning 'backwards' I have to turn it on, and slowly turn the speed knob from slow to fast, then it starts right up. Not a big deal, and frankly, is probably a Good Thing for safety. No oops-I-bumped-the-switch spontaneous startups. More tommorow when I've actually turned a full pen with it.

Front view: I used a light switch for power on/off control. I bought the 5k potentiometer at radio shock.. Fwd/Rev switch will be forthcoming, when I find my toggle switch


Top/side view: I put a spring to add extra tension. The motor is mounted on a piece of plywood (well, two pieces of 1/4" epoxied together) and the plywood is hinged for easy belt changes. The hinge pin is a removable type, and I will mount another half hinge behind the lathe bed so I can reverse the headstock to turn a bowl.

 

[btboone]

Gosh Brian, it seems dangerous to be jogging while turning. [] Looks like the motor should work pretty well. If it is wimpy on the low end, a flywheel could help that. It could be smaller than the one that came with it.

 

[Dario]

Nice idea...I think I have a similar motor lying around somewhere

 

[TomServo]

boone: I'm looking to bring EXTREME PEN TURNING into the limelight as the hardcore extreme sport that it is I can't wait to try out the Taig in reverse headstock "mode" - I mounted the lathe on a chunk of 1 1/4" MDF, so I can probably get away with mounting a toolrest directly on that board. since I can dial the speed way down, I can round out a bowl blank at as low as 100 RPM or possibly less.

Dario: the controller board was $29 from surplus center.. you can find similar ones on ebay also... it's rated for 8A @ 130V - the motor I have here is rated for 2 1/4 HP @ 230V and 1 1/8 HP continuous duty @ 130V - not sure of the amperages, but a typical DC motor 78% eff, 8A @ 130V is approx 3/4HP.

edit: the dark stuff on my workbench is leftover PR - whenever I've been fooling around with casting resins, I put the leftover on my workbench or lathe board - sure the color ends up a bit rainbow, but it keeps the MDF from staining with oil

 

[TomServo]

Just wanted to update - I made a couple pens today, the motor worked beautifully! I was able to run the lathe at under 30 RPM when sanding - sanding with the grain takes more effort but I feel it's worth it.. nice to have the piece rotating slowly enough to do it!

 

[TomServo]

Wanted to post an update - I cooked the speed controller the other day. I think a combination of "big motor" and "not so big controller" rolled together with the light duty expected of the controller caused a failure.. Nothing spectacular, it just won't put out voltage anymore. I spent $50 on two industrial units on ebay - these should do the job much better. I'll update when I've tried them out.. and I may sell the second one..

 

[Fred in NC]

Tom, probably fried the output transistors. They can probably be replaced. The transistors generate a lot of heat which must be dissipated. Most of these PWM controllers need additional heat sinking at the transistors. A small fan will help too.

 

[TomServo]

Fred: The controller never got warm - the motor did after 4 hours of turning, but the controller didn't even get past room temperature.. the body of the unit is a heataink (of limited capacity). I think the problem is that I was demanding more than it could give on occasion (when I was cutting some aluminum, and stalled the spindle), and it would overload/freak out and the motor would stutter. When I turned it off, and back on, it'd work fine again, but it made the lights flicker to the stutter, so I'd say it was probably pulling too hard on the diodes, or SCRs... I may try to repair it. Still haven't gotten the new controllers yet - I'll probably hook up my 1/4 HP AC motor (ol faithful) to get some critical work done before x-mas

 

[TomServo]

The new motor controllers arrived yesterday - after I'd put my induction motor back on, and turned my first! slimline. They're very high quality, come with a pot, spade terminals and are mounted on a piece of very well anodized 1/4" aluminum. They're definitely new in box, as advertised by the seller - with manuals. I'll hook one up in the morning (more pens to turn!) and post pics, and impressions.

 

[TomServo]

No pics still, but the new controller works great - very smooth control, very good speed control, it'll start the motor at any speed in both directions.. I put a reversing switch on it - you can't reverse it while the controller is on, of course. The controller doesn't even get warm... It'll drive the motor quite a bit past the 5000rpm, probably like 6500. I turned back the "MAX" speed setting to compensate. I can turn the spindle at about 15 rpm with smooth travel.

 

[TomServo]

I promised more pictures, and here they be


Motor controller behind the "control board"


Controls are good!