Re: [CAD_CAM_EDM_DRO] Steppers

Gene wrote:

>Sometimes I see people on the list talking about motor speeds in excess
>of 1000 rpm. How is this achieved? I can get nowhere near that.
>
>

It requires 3 things, I think:

1. the motors have to be well matched to the machine, meaning bigger
than most people
use. I put size 34 motors on a 150-Lb minimill, because I already had
the salvaged
motors. I was using a 49 V power supply.

2. Good stepper drives. The Gecko 201A is a pretty good drive, and
solves a number
of performance problems with other drives.

3. A very smooth train of step pulses, with extremely small variation
in time between
successive pulses, and also smooth acceleration and deceleration.

I demonstrated my Universal Stepper Controller at the 2003 NAMES show,
with it
spinning those size 34 motors at 1440 RPM, which translated to 90 IPM
when it drove
the 16 TPI leadscrews with a 1:1 belt drive.

Part of the trick is the USC produces a train of step pulses far
smoother than any software
ever could, as its step timing can be set with 100 nS granularity. Even
when pushing 48,000
microsteps/second out to the Gecko drive, the resolution was 1 part in
200, or half a percent.

For comparison, using EMC's freqmod step generation scheme with a 16 uS
period, you can't
even generate steps that fast.

Jon