[CAD_CAM_EDM_DRO] Re: Stepper Motor Power Calculations

Well then, that would be a good reason to ignore the advice I saw the other
day on one of these boards, suggesting that it's ok to run them hot until
they almost sizzle. I suspect that at high speeds the inductive reactance
gets so high that the voltage required to overheat the motor would be more
than the switching components could handle anyway, which is probably why we
don't see motor drivers with better high speed performance. I guess this is
one of those cases where there is a good reason nobody has done it already.

--Phil M.

----- Original Message -----
From: "Vlad Krupin" <vlad.cnc@...>
To: <CAD_CAM_EDM_DRO@yahoogroups.com>
Sent: Monday, January 23, 2006 5:32 PM
Subject: Re: [CAD_CAM_EDM_DRO] Re: Stepper Motor Power Calculations


> On 1/23/06, Phil Mattison <mattison20@...> wrote:
> [snip]
>
> > I would think
> > that the motor current ratings are for holding current, and could be
> > substantially exceeded when stepping at high speed without damaging the
> > motor, since heat dissipation is the main reason for current limitation.
>
>
> It is, indeed the main limitation. Out of curiosity I did some searching
and
> came up with this table: http://www.kjmagnetics.com/specs.asp
>
> Those are some seriously low temperatures! It shows that it does not take
> much heat to permanently damage a neodymium magnet. Depending on the motor
> design, I think, the magnets may have a hard time transferring heat to the
> body of the motor. You may not even realize that your motor is at risk
until
> it is too late.
>
> (probably 99% of you knew that already, but just how low the safe
operating
> temperature can be was news to me. So I figured I'd share what I found and
> maybe save somebody a bit of extra grief)
>
> Vlad
>
> [snip]
>
> --
> Vlad's shop
> http://www.krupin.net/serendipity/index.php?/categories/2-metalworking
>
>
> [Non-text portions of this message have been removed]
>
>