Re: [CAD_CAM_EDM_DRO] Re: L298 goes boom - AWO?

In a message dated 05-Aug-02 21:05:23 Central Daylight Time, KM6VV@...
writes:

> Now what I'm wondering, if the motor currents are off in either Gecko's or a
> Camtronics board (or other L298 driver), is the circuit protected against
> spinning the motor shaft (as in using a handwheel on the tailshaft of the
> motor)?

OK, ya talked me INTO it! I'll throw in MY 2¢ worth: I have just completed
my first "stepper motor thing" using the Gecko G210 drives (I have built
LOTSA unipolar machinery using my own drivers, plus a couple of early
Superior Electric drives). I built two lathes with recent Superior Electric
KML-092 motors using THEIR driver-box/PS. The Gecko drives have a "disable"
terminal, which, when GROUNDED, "open" the windings. It may be my
imagination, but it SEEMS that the motors spin even MORE freely
("finger-spinning") when the Gecko drives are DISABLED, than when the motors
are not connected at all! (Note: Those of you who have not fiddled with
steppers very much: If you simply short the wires of a stepper together, it
makes it QUITE difficult to "spin" the shaft! I do NOT mean this, here!)
The S.E. drives have the "All Windings Off (AWO)" input, which, as I recall,
can be made either HI or LO, depending how you CONFIGURE the inputs when you
install things. I haven't fiddled with the AWO switches I dutifully
installed on my control-panel much, but the couple of times I DID use them,
they ALSO seem to "open" the motor-windings even more than just shutting
things down. Hmmm... One of you electrical sages TELL us: Is this
possible, or only my learning-challenged imagination??? Jan Rowland


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