Re: What passes as Pulse Width Modulation in DC Motor Control?


"Jamie" <jamie_ka1lpa_not_valid_after_ka1lpa_@xxxxxxxxxxx> wrote in message
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Rich wrote:


"Rich" <notty@xxxxxxxxxx> wrote in message
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Okay, the only circuits I can find use tachometer control. I've not seen
any PWM circuits that speed regulate using the monitoring of voltage
across armature, or current through armature.


I stand corrected: I think this is one:

http://electronicdesign.com/Articles/Print.cfm?ArticleID=5763

Only one I seem to have found. I'll see if I can make it work with my
12v 2.5A DC brushed motor.

Wow, you finally found a PWM motor, circuit.

btw, that's not reversing.. (regenerative).

My original spec was for a bi-directional, PWM, constant speed, and *not* to
rely on a tachometer.

My motors seem to be designed for one direction only, so I'll ditch the
bi-directional requirement.

It also may be that perhaps PWM might not be so critical for slow speed. I
think I'll build two circuits:

http://electronicdesign.com/Articles/Print.cfm?ArticleID=5763

PWM, constant speed, no tachometer.

http://electronicdesign.com/Articles/Print.cfm?ArticleID=6199

Not PWM, consant speed, no tachometer. But it might be perfectly okay.

http://electronicdesign.com/Articles/Print.cfm?ArticleID=6168

I might even do this, just to mess with tachometer. But there will be plenty
of other tachometer-based circuits.

But, in general I seem to have found it hard to discover a circuit that's
PWM with constant speed control, that's *not* tachometer based.

.

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