Thread: Mars Lathe DC motor conversion.

Originally Posted by Michael G

If I had to use a treadmill motor I think I'd probably make up a large bolt on heatsink that would be in very good contact (thermal paste and so on) with the stator and then use a fan to blow as much air as I could across it. A finned Al flywheel on the rotor would probably not hurt either.

Michael

The cooling has to be applied directly to the armature.

A heat sink won't do that. The cooling effect would be too late to prevent damage to the windings.

You need lots of air blowing through the unit to keep the windings cool.

So a 12 V bilge blower is what I will be using.

Nice motor I got, but will have to modify the mounting bracket quite a bit, so the job can wait until I have less interesting things to do.

Rob

So, is anyone still using the DC treadmill motors?

I'm not, I still have a 1hp motor but it needs new bearings. I would be very tempted to put it on a drill press if I found one that needed a new motor. I almost bought a tough with no motor but decided against it. The on off use that they get on the lathe is just too much for them I think. A proper baldor dc motor may be a different story but they are just too expensive.

Cheers,
Ew

Originally Posted by Gammaboy

So, is anyone still using the DC treadmill motors?

I fully intend to.

I have a 1.5 HP heavy duty treadmill motor ready to go.

All I need to do it is get some time to hook it up, but that's a long way off at the moment.

The DC inverter is all there from the last DC motor which I "cooked"

I was going to use a cheap bilge blower to cool it, but that's no go as they can't be run continuously.

So it looks like I need either a powerful hair dryer or a small dust extractor to get air through the casing.

Has to be cheap.

Rob

Are DC motors smoother than single phase? As smooth as 3 phase?

Hi Bryan,
As smooth as a 3 phase is at 50Hz, but they don't seem to have rough spots like the 3ph motors i have do at certain frequencies with a VFD. The torque also comes in really differently, the motor will start to load up and then the power comes on in one big hit and just keeps on delivering. That probably has something to do with the controller too though.

Cheers,
Ew

Thanks Ewan. I have a treadmill motor and wondered if it would suit the TC grinder (currently 1~).
Sounds like they need a lot of airflow and that may not be healthy on a grinder.

What speed will it need to run at? If its 2800rpm or so i don't think it would be a problem with the original paddle fan. The main reason we went to separately powered fans is so they didn't overheat at lower revs. Also with the TC grinder you won't need a brake or be putting high loads on and off the motor so i don't think you will have a problem. As for clean air, a bit of ducting from the back of the motor away from the grinding dust should work fine.

Ew