Newsgroups: comp.robotics
Path: brunix!uunet!gatech!asuvax!ennews!mcdphx!schuch
From: schuch@phx.mcd.mot.com (John Schuch)
Subject: Re: Stepper motors
Message-ID: <1993Apr5.213803.10285@phx.mcd.mot.com>
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Organization: Motorola Computer Group, Tempe, Az.
References: <1pdah8INNqdc@dns1.NMSU.Edu> <1993Apr1.181351.18276@magnus.acs.ohio-state.edu> <64@mlb.win.net>
Date: Mon, 5 Apr 1993 21:38:03 GMT
Lines: 20

In article <64@mlb.win.net> mbayern@mlb.win.net (Mark Bayern) writes:
> 
>>In article <1pdah8INNqdc@dns1.NMSU.Edu> mcole@scotty (COLE) writes:
>>>I am having trouble driving a stepper motor.  I am driving each of the
>> Could be that you're trying to drive them too FAST. I have found that many
>Its the standard stepper resonance problem -- as was stated in
>......
>into position.  The rotor actually 'rings', and if you can plot
>rotor position accurately enough you can see this. Resonance

Actually, if you have an o-scope it's pretty easy to see the ringing.
Just place a low-ohms resistor (one or two ohms) in series with one
of the windings as a current shunt. place the scope across the resistor.
Run the motor at a constant speed and adjust the timebase accordingly.
The ringing is easier to see at lower speeds (around 10 steps/sec).
The ringing generates back-emf which you can see on the scope.

John


