Alt-BEAM Archive

Message #03109



To: Wouter Brok w.j.m.brok@stud.tue.nl
From: Steven Bolt sbolt@xs4all.nl
Date: Sun, 9 May 1999 08:25:45 +0200 (CEST)
Subject: [alt-beam] Re: non-block-wave signal for steppermotor



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On Sat, 8 May 1999, Wouter Brok wrote:

> In general stepper motors are driven with block-form waveforms at the
> inputs. I don't think this is favorable from the energetic point of view;
> what I mean is this: When one input of a bipolar stepper-motor is made high
> (suppose this is the driving voltage level, so all the others are low) the
> motor-axis will turn in the appropriate direction because it is attracted
> by the powered coil. At a certain point however the axis is at the position
> from where on the powered coil will slow the axis down. At that point the
> input which was high should be made low and the next input should be made
> high as to power the next coil so that the axis is attracted to the next
> position. However, I do think it doesn't happen this way generally: the
> input will be made low just to late, so the motor-axis will be slowed down.
> This results in a waste of energy.

The common waveform for single-coil bipolar steppers (as found in
clocks) is like this:
__
| |
---| |---| |----
| |
--

With a certain minimum gap between the alternating pulses.
A good and often used alternative is the waveform caused by putting
a capacitor between a high going pulse and the coil:

|\
| \
---| \---| /---
| /
|/


Attached are examples of the circuits used.

Best,

Steve

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# sbolt@xs4all.nl # Steven Bolt # popular science monthly KIJK #
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Attachment: stepper_driver.gif

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3110 Sun, 09 May 1999 09:57:30 +0200 [alt-beam] Re: An organized list of most of the recent top topics beam@corp.sgi.com Wouter Brok >Personalities (BEAM People)
> Have you introduced yourself yet?

No, actually I haven't yet (being the last one):

Wouter Brok 22 yrs old.
Place: Eindhoven, The Netherlands.
Study: technical physics, Eindhoven University of Technology
Music: portishead, tool, the sneaker pimps, moloko, the cure ...
Respect: Alexander Shulgin
Job: Fysicawinkel (physics-shop): helping people by measuring noise and
vibrations caused by neighbours, roads, companies so that they can go to
court or go to the townhall to get thing changed, as well as answering
physics question ('I made up a perpetuum mobile, can you check it for me?',
etc)
Hobby: electronics, BEAM, for the rest I don't have time for anything
because of my job, study and girlfriend (not in that order perhaps).

Thank all of you for being active on this list; I enjoy it.

Regards

Wouter Brok



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