RE: [CAD_CAM_EDM_DRO] Re: L297/L298

> Subject: [CAD_CAM_EDM_DRO] Re: L297/L298
>
>
> --- In CAD_CAM_EDM_DRO@yahoogroups.com, "Phil Mattison"
> <mattison20@...> wrote:
> >
> > I've been experimenting with various designs for bipolar
> > stepper motor drivers and I'm curious if anyone has had a
> > similar experience. Is it just my perception or is the
> > L297/L298 combo a piece of junk? It seems no matter
> > how I configure it the thing just runs way hot if it
> > carries anything near its rated current.
>
> Phil:
>
> I'll give a somewhat contrarian point of view here.
>
> The L298 is a bi-polar device and consequently
> generates more heat in operation than its FET
> counterparts (e.g. A3977.) With a good heat sink,
> a fan and operated within specifications, L298's
> operate just fine.
>
> From a price point of view, they are still quite
> competitive with their FET IC counterparts. For
> example, the L298 can be purchased from Jameco
> for less than $3 quantity 1. A heat sink for
> the multiwatt15 package can be obtained from
> Mouser for about $1 (Mouser #: 532-655010B3400G ~$1).
> Of course, you also need some free wheel diodes like
> the 1N5822, but those are inexpensive as well.
>
> From a convenience point of view the FET IC's win
> hands down. If you are only building one, the FET's
> are the way to go. If you are thinking about building
> hundreds, it is not as easy to dismiss the L298.
>
> The L297 is at best a half step chip. These days
> a micro-step solution tends to be preferred. It
> is fairly easy to dump the L297 and replace it with
> a microcontroller. My most recent table top drive
> electronics are posted on-line at the following URL:
>
> <http://gramlich.net/projects/cnc/axis4/index.html>
>
> It works just fine. I make chips with my Sherline
> CNC conversion using the driver above. I'm still
> tweaking my total software toolset, but the basic
> microstepper stuff using the L298's works quite well.
> No, I can't step at 500kHz, but realistically I doubt
> that most table top machines need to run quite that
> fast. My driver won't win any IPM drag race derby's
> but it will make chips just fine.
>
> This is probably not be the consensus view on L298's.
>
> -Wayne
>
>
>
>
>
>
>
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