smallest highspeed stepper motors?

Thread Starter

gewimduck2

Joined May 11, 2018
3
In my project I've been using galvo scanners for rotating small mirrors but they seem like an overkill at this point for several reasons:

1) Even though I use the slowest and smallest scanners out there, they are still over 100 grams each, in a device where every gram matters,

on top of that, their drivers are rather large (8cm x 6cm) and need special dual rail +-12V power supplies and +-5V DAC circuits to run. These all require space of their own and I need everything take up as much little space as possible.

2) While they can achieve the rotation speeds I need they seem to exceed it. The cons of using galvos which is space for all the electronics seems to outweight the pro of the high speeds which aren't used to the fullest anyway.

Since steppers just need one 3.3, 5 or 12V PSU and one stepper driver I thought I'd give them a try.

The smallest steppers I am aware of which are readily available are NEMA 14, which is huge for this.

The requirements are simple:

1) torque is extremely low as a small 10x10mm 1mm thick mirror is rotated which is glued onto it.

2) acceleration and rotation speeds are important and demanding though: 50 ms for a 5 degree rotation

I've found a stepper but the rotation speed is abysmal for this. The 28BYJ-48

I guess my questions are these two:

1) Can small enough steppers meet this criteria (low torque but high speed requirement) at all?
Bigger motors seem to achieve the desired result

2) which stepper(s) should I check.

3) can they not make those loud sqeaky noises like in CNCs and 3d printers?

 

Papabravo

Joined Feb 24, 2006
14,403
Small and high speed are requirement that are in fierce opposition to each other. When you make the motor small you limit the torque. When you try to operate a high speed you quickly run out of torque. This is probably why RC planes do not use stepper motors. I don't know if RC servos will work for you, but if you've never considered them you should give them a try.
 

Thread Starter

gewimduck2

Joined May 11, 2018
3
Like I said my torque requirements are very low.

rc servos are a bit slow and too noisy. Their torque is pretty impressive but useless here
 

Thread Starter

gewimduck2

Joined May 11, 2018
3
First one looks perfect form wise and very well may work, but I cant find a datasheet or a way to contact the seller.
 

Alec_t

Joined Sep 17, 2013
11,640
Do you need to rotate the mirror to an arbitrary angle with a precision of a fraction of a degree, or just move it rapidly between two fixed positions? If the latter, then a small solenoid might do the job.
 
First one looks perfect form wise and very well may work, but I cant find a datasheet or a way to contact the seller.
Good luck on finding a data sheet...I had to measure the coil ohms myself and that was a while ago. You might find some value in searching on Ebay for similar ones. I have seen similar ones in many places, including there. I guess my thinking is that they are cheap enough to buy a couple and test. The surplus market can be cheap, but otherwise lacking.
 

MisterBill2

Joined Jan 23, 2018
6,998
Alec T certainly asked the right question, which reduces to how accurate and how fast does it need to be? The performance requirements control everything else. There are also piezo electric actuators that are very fast, but with limited motion and a higher cost. It all gets back to performance requirements.
 
Top