Hi,

This post is more of a curiosity at the moment with potential to become something if I find a solution/idea. I am an extreme novice to all of this, especially motors and controlling them so please be gentle and patient. I most likely wont know many of the terms you use so please explain it to me like I am a child and just put yourself in my shoes before going on rants about my skills/knowledge.

I'm wondering as to weather or not a coreless motor can be controlled in small movements, like 35 degrees in one direction and then reverse back to its original spot? I am extremely limited on space otherwise I would try a servo and control it that way however there just simply isn't space for that. I would not be surprised if the function I am after is just not possible, like I said, currently its just curiosity that could lead into a potential project if it is possible.

I've attached a link to motor that I was looking at that would probably fit for your size reference or if you can suggest something better.

https://www.aliexpress.com/item/100...0544031&spm=a2g0o.ppclist.product.mainProduct

Thanks.

 

Welcome to AAC.

With a position sensor you could do it more or less. But it will require working out they dynamics of the motor and probably using an H-Bridge to electrically brake the motor or return it from overshoot.

There are very small steppers that would be more suited, depending on the torque requirements. This is a random example.

 

Agree with Ya’akov. A stepper motor is what you want.

 

Welcome to AAC.

With a position sensor you could do it more or less. But it will require working out they dynamics of the motor and probably using an H-Bridge to electrically brake the motor or return it from overshoot.

There are very small steppers that would be more suited, depending on the torque requirements. This is a random example.

Thanks for the quick response! I cant imagine the torque requirements are very high. So a stepper motor is more suited? Fine by me as long as I can find one that fits.

Agree with Ya’akov. A stepper motor is what you want.

Thanks as well! That confirms it for me, a stepper motor it is.

How does this one look? It was just one of the first I saw and it looks extremely tiny so I can definitely go bigger, but the smaller the better so would this one work?

https://www.aliexpress.com/item/100...0545381&spm=a2g0o.ppclist.product.mainProduct

 

Hard to tell since no torque or step size is given.

 

Hard to tell since no torque or step size is given.

I could be talking nonsense here but is it not 18 degrees for step angle because its 2 phase? Or is that not irrelevant?

 

No, the step size depends on the number of magnetic poles, not the number of phases. Standard steppers are 1.8°.

 

No, the step size depends on the number of magnetic poles, not the number of phases. Standard steppers are 1.8°.

Okay, well they’re pretty cheap, would it be somewhat safe to assume they’d be standard? Does 4 wire have anything to do with it?

 

The alternative, using a coreless motor, would be to have a gearbox, and use a smaller motor. As mentioned already, if the motor dynamics could match the application, and if there were adequate feedback resolution, and if the load was quite constant, then there is a chance it could work well enough.

 

Okay, well they’re pretty cheap, would it be somewhat safe to assume they’d be standard? Does 4 wire have anything to do with it?

I would not. I would find one that gives specs. The four wires are for the two phases. You move the motor one full step by going through the 4 combinations of polarity for the two coils in a specific sequence.

What is this thing going to be moving? I can’t imagine it has much torque.

 

I would not. I would find one that gives specs. The four wires are for the two phases. You move the motor one full step by going through the 4 combinations of polarity for the two coils in a specific sequence.

What is this thing going to be moving? I can’t imagine it has much torque.

Ahh I see. Its just going to rotate a small bit of plastic, probably no more than 10g in weight. I did find one with the step angle at least. 22.5°

https://a.aliexpress.com/_mr9uS6W
I might just buy some anyway since they’re cheap, see how it goes with this and go from there. At least I’ll have an idea of what works