Re: [CAD_CAM_EDM_DRO] stepper controller - help

In a message dated 11/16/2002 8:36:48 AM Central Standard Time,
dmauch@... writes:

> Not quite correct. The 65V is the maximum voltage that the manufacture
> recommend those motors to run at. Those motors have a per phase resistance
> of 1.52 ohm so the actual voltage would be about 3.5V. So I would recommend
> a 36VDC power supply up to 65V maximum. But if you use the L298 then you'd
> better stick with the 35VDC power supply.

Dan: For quite a time, now, I have been slightly frustrated that 98% of the
members of our group are more "machinists" than "E.E.'s", so they clearly
have NO clue how a stepper with windings rated at, say, 4 amps, 3 volts, need
a 24 to 80 VDC supply. The concepts of "current-limiting", voltage-dropping
either via the nasty huge "L-R resistors" of the old "six-wire unipolar days"
or the more recently-espoused "chopper drive" technique float way above most
of our heads.

Now I readily admit I am too ignernt to explain all this adequately in few
words, but I am CERTAIN some E.E.'s in here like you, Mariss, etc., can do so
admirably. Thus, it seems a short "tutorial" on what L-reactance does when
stepping-rate exceeds three or four steps per second, and how modern drives
"deal with that" (and why 24 VDC or more is needed in a supply for "four volt
windings", etc.) would be very, very useful to us "in here"!!! Am I right,
guys?

Jan Rowland, old troll


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