CAD CAM EDM DRO - Yahoo Group Archive

RE: [CAD_CAM_EDM_DRO] Re:low cost stepper driver

Posted by John Dammeyer
on 2012-10-02 22:15:21 UTC
Adrian,

Rarely does a connector or a switch disconnect immediately.

Also, a stepper motor has two windings which makes it a form of
transformer. If there is lots of current flowing through one of the
windings and you only disconnect that one the collapsing magnetic field
generates a whopping big voltage spike in the second winding which is
still coupled to the driver transistors. No visible spark will be seen.

Again, there's no guarantee that both windings are disconnected at exactly
the same time (we're talking micro-seconds here) when there is power
flowing through them.

John


"ELS! The Solution"
Automation Artisans Inc.
http://www.autoartisans.com/ELS/
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> -----Original Message-----
> From: CAD_CAM_EDM_DRO@yahoogroups.com
> [mailto:CAD_CAM_EDM_DRO@yahoogroups.com] On Behalf Of artgartg
> Sent: Tuesday, October 02, 2012 12:00 PM
> To: CAD_CAM_EDM_DRO@yahoogroups.com
> Subject: [CAD_CAM_EDM_DRO] Re:low cost stepper driver
>
>
>
> --- In CAD_CAM_EDM_DRO@yahoogroups.com, "John Dammeyer"
> <johnd@...> wrote:
> >
> > You cannot guarantee that when you unplug a powered stepper
> motor that the
> > connector or switch won't have the contacts bounce on/off for a few
> > micro-seconds or even milli-seconds. During that time the
> stepper motor
> > windings behave just like the ignition coil and the
> resultant high voltage
> > spike will kill the drives.
> >
>
>
> This is what I was wondering. I appreciate that you get a
> back-EMF spike when it's disconnected, but it's
> *DISCONNECTED* - it's not the driver transistor switching off
> so it shouldn't reach the driver. But intermittent
> connections (or a spark that jumps the gap, as Tony
> suggested) is possibly the reason.
>
> I note that some good quality drivers have tranzorbs which
> can presumably absorb more energy than the internal diodes
> (and also don't dump it into the power supply).
>
>
> -adrian
>
>
>
>
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Discussion Thread

turbulatordude 2012-06-25 17:51:22 UTC low cost stepper driver Ron Thompson 2012-06-26 04:33:51 UTC Re: [CAD_CAM_EDM_DRO] low cost stepper driver Jamie Cunningham 2012-06-26 04:55:38 UTC Re: [CAD_CAM_EDM_DRO] low cost stepper driver Tony Smith 2012-06-26 06:06:24 UTC RE: [CAD_CAM_EDM_DRO] low cost stepper driver Ron Thompson 2012-06-26 06:53:07 UTC Re: [CAD_CAM_EDM_DRO] low cost stepper driver Tony Smith 2012-06-26 07:16:46 UTC RE: [CAD_CAM_EDM_DRO] low cost stepper driver Dan Mauch 2012-06-26 07:43:39 UTC RE: [CAD_CAM_EDM_DRO] low cost stepper driver jeffalanp 2012-06-26 11:54:37 UTC Re: low cost stepper driver Nelson Collar 2012-06-26 12:58:22 UTC Re: [CAD_CAM_EDM_DRO] Re: low cost stepper driver Dr Stuart Harrison 2012-06-26 15:00:53 UTC RE: [CAD_CAM_EDM_DRO] low cost stepper driver jeffalanp 2012-06-26 16:38:30 UTC Re: low cost stepper driver Nelson Collar 2012-06-26 18:18:08 UTC Re: [CAD_CAM_EDM_DRO] Re: low cost stepper driver jeffalanp 2012-06-27 11:50:50 UTC Re: low cost stepper driver David G. LeVine 2012-06-27 17:33:58 UTC Re: [CAD_CAM_EDM_DRO] Re: low cost stepper driver John Dammeyer 2012-06-28 17:35:07 UTC RE: [CAD_CAM_EDM_DRO] Re: low cost stepper driver Lester Caine 2012-06-30 06:45:37 UTC RE: [CAD_CAM_EDM_DRO] low cost stepper driver John Dammeyer 2012-06-30 06:50:12 UTC RE: [CAD_CAM_EDM_DRO] Re: low cost stepper driver artgartg 2012-09-30 19:44:58 UTC Re: low cost stepper driver Ron Ginger 2012-10-01 04:23:09 UTC Re:low cost stepper driver turbulatordude 2012-10-01 04:41:13 UTC Re:low cost stepper driver Jamie Cunningham 2012-10-01 05:01:05 UTC Re: [CAD_CAM_EDM_DRO] Re:low cost stepper driver rwwink 2012-10-01 06:13:45 UTC RE: [CAD_CAM_EDM_DRO] Re:low cost stepper driver Jeffrey Birt 2012-10-01 06:49:39 UTC RE: [CAD_CAM_EDM_DRO] Re:low cost stepper driver John Dammeyer 2012-10-01 08:34:28 UTC RE: [CAD_CAM_EDM_DRO] Re:low cost stepper driver David G. LeVine 2012-10-01 12:22:27 UTC Re: [CAD_CAM_EDM_DRO] Re:low cost stepper driver Tony Smith 2012-10-01 13:15:24 UTC RE: [CAD_CAM_EDM_DRO] Re:low cost stepper driver Ron Thompson 2012-10-01 13:59:56 UTC Re: [CAD_CAM_EDM_DRO] Re:low cost stepper driver turbulatordude 2012-10-01 16:57:37 UTC Re:low cost stepper driver Dr Stuart Harrison 2012-10-01 20:27:49 UTC RE: [CAD_CAM_EDM_DRO] Re:low cost stepper driver Tony Smith 2012-10-01 22:51:44 UTC RE: [CAD_CAM_EDM_DRO] Re:low cost stepper driver Lester Caine 2012-10-02 00:23:21 UTC Re: ***SPAM*** [CAD_CAM_EDM_DRO] Re:low cost stepper driver wotisname 2012-10-02 04:20:51 UTC Re:low cost stepper driver artgartg 2012-10-02 12:10:13 UTC Re:low cost stepper driver artgartg 2012-10-02 12:10:41 UTC Re:low cost stepper driver artgartg 2012-10-02 12:10:56 UTC Re:low cost stepper driver Joe 2012-10-02 12:11:27 UTC Re:low cost stepper driver Stephen Muscato 2012-10-02 12:31:11 UTC Re: [CAD_CAM_EDM_DRO] Re:low cost stepper driver John Dammeyer 2012-10-02 22:15:21 UTC RE: [CAD_CAM_EDM_DRO] Re:low cost stepper driver Tony Smith 2012-10-03 02:46:10 UTC RE: [CAD_CAM_EDM_DRO] Re:low cost stepper driver turbulatordude 2012-10-03 04:36:09 UTC Re:low cost stepper driver Tony Smith 2012-10-03 08:31:49 UTC RE: [CAD_CAM_EDM_DRO] Re:low cost stepper driver