Re: Stepper motor speeds

At 04:32 04/11/2002 +0000, you wrote:

>I did some research on the 23 frame motors we're using. They come from
>Shinano:
>http://www.shinano.com/stepper.htm
>
>You can download a data sheet for the 23 frame motors and torque
>curves are provided. Typical step rates are nowhere near 1200 RPM.
>Typical values are 800 to 2000 pps. At 200 steps/rotation this is
>equivalent to 600 RPM tops, and most are closer to 300 RPM.
>
>This makes me think I'm not doing so badly with 3300 pps. I'd still
>like to hear from anyone getting faster rates from 23 frame motors.

Brian -

I have a Taig mill that uses Taig's own unipolar/bi-level chopper drive -
it seems to max out at about 0.3 IPS, which is about 2400 (half)
steps/second. The motors are relatively low current, high voltage (200
oz-in motors but only 1A/phase) - may explain why the performance is not as
good as your figures.

My DivisionMaster automatic indexer, which uses L297/L298 with a 19V
supply, can drive size 23 motors at up to around 5000 half-steps/sec.

One factor here is that the indexer is probably seeing a much smaller load
(72:1 or 90:1 worm drive, relatively light table with ball bearings
everywhere, vs 20 TPI leadscrews & significant sliding friction to
overcome). Another factor worth looking at may well be jitter (or lack of
it) in the pulse train - as someone else has observed in this thread,
variations in pulse timing look to the motor like demands for rapid
acceleration/deceleration, and therefore affect the max speed that you can
attain without losing steps.


Regards,
Tony