Decoding stepper motor model numbers

Sorry guys, but steppers aren't my thing at all. Other than the obvious Nema numbers, I have no clue what the rest of the number mean so it's difficult for me to search for what I need.

I'm after some more stepper motors Nema 23 2A 1.8 degree and 8.6V (though I don't know just how critical that voltage is, it should be a 12V supply). It needs to have a relatively high holding torque. The motor recommended is Nema 23 57BYGH310-D which is available from Circuit Specialists at a very good price in my opinion. Job done at US$23.89 each. BUT to ship them out to me here in Oz is basically extortion! The single price wasn't too bad, but once I ordered more the shipping seemed to go up exponentially. I'll get in contact with them to check what's going on with their shipping calculator, but in the meanwhile hoped somebody could help with alternatives? I guess the codes actually mean something, and if I could find out what I may be able to find closer alternatives. I haven't been able to find anything on the net so I'd be grateful for some direction with this.

Thanks

A high voltage rating on a stepper motor like the 8.6 volts is an indication the speed will be very limited and torque will fall off rapidly. Steppers are inductive devices that generate back emf which looks to the driver like a high resistance. So low inductance motors will perform better for a given driver voltage, and increasing the drive voltage greatly improves torque as the speed goes up. My homebuilt uses nema 34 rated 2 volts and I drive them with 80 volt rated drivers on a 68 vdc power supply. I get over 1500 rpm without a problem.

Ok thanks Gary, I may have to do a bit more reading about steppers and the voltage rating. Well just steppers in general. I've only really assembled stuff before where the steppers have been supplied, and haven't scratch built where I've needed to make the selection.

Speed isn't important in this instance. The application is a small rotary table so it's not even like these would be running continuously. Maybe a little for a 4th axis type setup, but generally it will be indexing. That's why I figured the holding torque was relatively important. Frankly NFI what I'm doing here, but the design I'm working off (and a clone of that also) uses the above motor so I figured why reinvent the wheel.

Gary (or others) why was a stepper motor with a relatively high rated voltage suggested for the application I'm intending? Would it have a higher torque than an otherwise similar motor but lower voltage? What are the advantages/disadvantages of the different voltage rating motors?

I'm using a TB6560 to drive these, so If I understand correctly, I could run virtually any rated voltage stepper at 12V and most of them even at 24V just so long as I limit the current to not more than the stepper motor's max? I was thinking of a 2.8A 3,2V motor @ 1.9 Nm. Any thoughts on that? I hoped it would be close enough for government work to the suggested motor.

I'm not locked in to 12V and would I be better to run this at 24V? I was going to use 12V as it's easy to get, but noticed the driver board suggested 24V.

Good reading here. Also drives well matched to motors. In general, you get what you pay for with drives and controls.

Support | GeckoDrive

Ok thanks for that Bruce. I'll study that site when I get a chance. In the meanwhile I just need to get one Nema 23 motor ordered. I think I may have been over thinking it, and I don't think this application really needs the torque others had been using. I think one person used an xxx motor, then a whole pile of people just followed along. The motor will be going through a 90:1 ratio and I think once the transmission is finessed it won't have a huge amount of friction, nor will it be able to be back-driven by cutting forces etc. I'll just order a more common 2.8A motor with a smaller torque. I'll just get the one at this stage and if it's not enough I can re-order a larger one and use this one elsewhere.

Thanks for those who provided the help and direction.