RE: [CAD_CAM_EDM_DRO] wave drive

I had thought (until I read Art's post) that, from the perspective
of the motor, microstepping IS effectively wave driving. Although
a modern microstepping controller uses PWM to achieve efficiency
in the electronics, the motor sees the average current supplied.
In the limiting case of microstepping (with many many microsteps),
over the course of a full cycle of steps the motor winding sees a
complete sinusoid (while the other winding sees a cosinusoid). As
the microsteps come into a more reasonable range (8, 10 or 16 usteps
per full step), the average current waveform is limited to discrete
steps, but the levels still reflect the sinusoidal pattern.

Other than for reasons of efficiency, I could make a pair of class
AB linear driver amplifiers that supplied DC currents to the motor
in the same ratios and still get the same positioning effect.

How does this differ from wave driving?

John Haddy
Sydney, Australia

> -----Original Message-----
> From: Art [mailto:fenerty@...]
> Sent: Wednesday, 17 December 2003 10:55 AM
> To: CAD_CAM_EDM_DRO@yahoogroups.com
> Subject: Re: [CAD_CAM_EDM_DRO] wave drive
>
>
>
> > i have a question about stepper motor
> > if i need high speed from unipolar motor do i need
> > 1 wave driving
> > 2 half step
>
> 3) MIcroStepping...
> >
> > 2 what is the benefit of using wave driving?
> > hope to get answer quiqly i finished my machine and decide which way
> > to drive it (the best way)
>
> There is none. Well, I suppose the electronics are easier, but poor
> performance is typical from wave drive in most instances..
>
> Art
>
>
>
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