Re: [CAD_CAM_EDM_DRO] New file uploaded to CAD_CAM_EDM_DRO

In a message dated 23-May-01 22:20:51 Central Daylight Time, KM6VV@...
writes:

> Possible change: Put the TIP120's with their emitters to ground, and
> pulling the "coil ends" down the Collectors would then all go to +24v,
> through a 10 ohm (or appropriate) L/R resistor. I haven't built the
> circuit, I just found it! OK, whose gonna try it? Jan? Bill??
>

Gawrsch, yes! I had forgotten this was an emitter-follower circuit! UGH!

The emitters SHOULD be @ ground, and the Collectors to the windings! Then,
the commons to the motor-windings (taps) should be THROUGH the low-R, high-W
resistors to +24 VDC!!! Of course!

General Instrument sells (did sell?) an IC... 29G41??? that had four
"phase-outputs" for driving Darlingtons, an half-step input, and "all
windings off" input, I think. It was much more useful for doing
stepper-drives (unipolar!) than kludgery, but it cost as much as a year-old
Toyota! 18-pin DIP. I used a dozen before I "grew up" and began buying
"store-bought" ready-made driver/power-supply packages. I am now looking
seriously at the Gecko circuits! Look nice! We'll see...



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