Re: Stepper motor speeds

At 23:58 03/11/2002 +0000, you wrote:

>At 4:26 PM +0000 11-03-02, turbulatordude wrote:
> >Size 42, 300 to 600 RPM, 800 in-oz or more low-speed torque.
> >Size 34, 600 to 1,200 RPM, 150 to 450 in-oz low-speed torque.
> >Size 23, 1,200 to 2,400 RPM, 50 to 150 in-oz low-speed torque.
> >Size 17, 2,400 to 4,800 RPM, less than 50 in-oz torque.
>
>This seems too fast to me. Perhaps you would comment on this. Looking
>at a 23 frame motor, in half step mode (400 steps per rotation), 1200
>RPM means 480,000 steps per minute or 8,000 steps per second. I am
>currently experimenting with 23 frame motors on Sherline tools using
>both the Xylotex bipolar driver and a unipolar driver of my own
>design. I'm stalling out at 3300 steps per second tops. It seems
>unlikely that this tool will ever run twice as fast as I'm seeing,
>and you list 1200 RPS as the low end.
>
>I'm feeding both drivers with 24 volts.

Supply voltage, probably. As Mariss keeps reminding us, double the supply
voltage & you double the top speed. Unfortunately, you are close to the
limit for what the Xylotex board will handle, so you are not going to get a
doubling of top speed here unless you can use motors with higher current
ratings (which will have lower inductance). In other words, get as close to
the 35V, 2.5A/phase limits as you possibly can.

Interestingly, one of the things that the numbers above seem to indicate is
that gearing down a size 23 motor by 2:1 gets you pretty much the same
place as using a size 34 motor driving direct, and potentially for less money.


Regards,
Tony