Re: [CAD_CAM_EDM_DRO] Approx max rpm for this stepper motor?

In a message dated 05-Apr-01 19:18:30 Central Daylight Time,
janders@... writes:

> I have a pair of Vexta PH299-01-A7 34 frame motors I want to use on this
> lathe slide setup I'm putting together. When I got these, I was told
> somewhere between 320-480 oz/in, can't remember. Dataplate only says
> 3V, 4A. Using Compumotor OEM 650 drivers at max current, anyone care to
> hazard a guess how fast I might drive these, RPM-wise, assuming I can
> generate the pulses fast enough?
>
>

It almost-certainly makes a difference if they are bipolar, but I'm GUESSING
they are unipolar (6 wires). This is a standard winding-size for unipolar.
You can see the specs for the Superior Electric M)-92-FD08 which is also
3V/4A. Probably exact competitive swap. RPM-wise, depends upon how-well you
can make your software or controller ACCELERATE and DECELERATE. The graphs
in the S.E. catalog show the "max. limits", and I am thinking (too lazy to go
look, to confirm) this motor can be stepped up to, oh, 3000 RPM, but ONLY if
you have a very fine driver and proper software!

If you expect only to "begin stepping" at some fixed rate, and "stop
suddenly", and expect no skips or missed steps, the max. possible with
"average" lead-screw load for this size motor is somewhere in the ballpark of
400 Hz. I know. I have a home-brew CNC lathe using the MO-92-FD08 for
years, now, and that's the way it is!

I have also recently completed two new ones using KML092F07 motors (bipolar)
and they are about TWICE as much torque, but slightly LESS DC-power-in! Much
more efficient motors, jus' like da book say!

I dunno anything about the Compumotor OEM-650 drivers, nor whether they are
unipolar, R/L, or chopper. So, no comment on that question.

Lotsa luck! Don't drop 'em! Jan Rowland, Troll


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