Good U$59 motor

[Achiles]

i think it´s a good motor for the price:
BLWR235S-36V-4000-04

[kayakerca]

i think it´s a good motor for the price:
BLWR235S-36V-4000-04

My first winder stepper motor (for the winding aspect) had rated torque of 47 oz./in. and I could stop the motor before AWG 42 wire would break. I changed the motor to one with rated torque of 376 oz./ in. which worked just fine. The motor you are referring to has rated torque of 62 oz./in. I think you could find that that motor may not provide sufficient torque to be used effectively for winding. That said, I could be way off on this and it wouldn't be the first time that's happened. If you like it, give it a try.

[David King]

It's good because it's a brushless DC servo motor not a stepper and presumably it has an encoder and will keep trying to get to the proper count no matter how many times you stall it.

[Joe Gwinn]

How much torque is needed for winding?

I built my own Schatten-style winder some years ago. The motor wasn't large, and the max torque was something like 7 in-oz, measured at the bobbin by clamping a long arm onto the bobbin axle and letting the far end of the arm press down on the pan of a scale. This torque was adequate for winding fine wire.

The max winding tension for AWG #42 is something like 35 grams (according to the BAE Wire tables, from memory). There are 28 grams per ounce, so that's 35/28= 1.25 ounces. A typical bobbin is 3" long by 0.5" wide, so the maximum lever arm is 1.5", and the max torque is (1.25)(1.5)= 1.875 oz-inches. A similar calculation can be made for other wire gauges. The thicker the wire, the bigger the motor needed.

Significant torque is lost in the mechanical components between motor and bobbin. For example, back in the day, I had two purchased motors of the same make and model, differing only in the kind of bearings used, plain oiled bronze sleeve or ball bearing. The ball-bearing motor delivered significantly more torque than the bronze bearing. A winder will usually have more bearings than just the motor. In a Schatten-style winder, there are the two bearings that support the bobbin axle. In my winder, these bearings were also plain bronze. All in all, it's safest to buy a motor with a factor of two or three more torque than needed at the bobbin, to be sure that enough torque always makes it to the bobbin. A too-large motor can be tamed by reducing the drive voltage. A too-small motor cannot be helped.

[David Schwab]

I was able to stop the motor on my Schatten just by gripping the wire tight. The wire wouldn't break either. It was a fairly weak motor. But I was able to wind pickups with it just fine.

The new motor is faster, which is better.