Re: stepper current

--- In CAD_CAM_EDM_DRO@y..., JanRwl@A... wrote:

> In a message dated 26-Apr-01 06:51:29 Central Daylight Time,
> rsidor@t... writes:
>
>
> > Question do I set the current for .5 amps now due to
> > twice as many ampere turns?
> >
>
> No, you can still push one amp through 'em. But maybe they will

heat up a

> bit more than before, since "all the copper" is conducting.

However, the

> MAIN consideration is that the INDUCTANCE is now FOUR times as

great

> (proportional to the square of the number of turns), so the maximum
> stepping-rate will be SEVERLY reduced. You just have to

experiment, since

> there would be no "specs" for this lashup, it never having been
> intended/anticipated by the original motor's designers.
>
> So long as you don't exceed twice the max. (half-) coil voltage at
> stand-still, and never exceed 1 amp, I guess all should be OK, if

you don't

> need to step faster than, say, 200 or 300 steps/second.
>
> My first experience with steppers was with unipolar motors (center-

tapped

> windings), and I got a "feel" for the kind of torque at a given

current and

> coil-voltage. Then a couple of years back, I built two lathes with

bipolar

> motors of the same physical size as those unipolars I had used

before, and

> WOW! They have FOUR times as much torque, and use LESS current at
> stand-still (driver drops current back to 50% after several

milliseconds of

> no steps being received). MUCH better! My max stepping-rate on my

machines

> is about 450 sps.
>
> Lotsa luck! Jan Rowland
>

Thanks for the info. I am beginning to see that there is a need to
experiment to get the best performance from each type of motor.

>
> [Non-text portions of this message have been removed]