RE: [CAD_CAM_EDM_DRO] Re: Stepper Dissasembly

It's all a matter of knowledge,experience and attentiveness to detail. The
experienced person will test the "free" motor before trying to use it with a
driver, even if it is from a college lab discard pile. As far as burning
through six controllers, the word 'insanity' comes to mind. It is the insane
person who tries the same thing several times, and expects a different
result.

-- Carol & Jerry Jankura
Strongsville, Ohio
So many toys, so little time



-----Original Message-----
From: Chris Stratton [mailto:stratton@...]
Sent: Tuesday, May 29, 2001 9:45 PM
To: CAD_CAM_EDM_DRO@yahoogroups.com
Subject: Re: [CAD_CAM_EDM_DRO] Re: Stepper Dissasembly

> Hi,
>
> I understand your point of view, but I have to deal with situations
> when "junk goes wrong".
>
> I had someone (no one on this group) that hooked up and destroyed 6
> drives in succession on a motor he had liberated from a dumpster. I
> had him send me the offending motor and it had a shorted turn on one
> phase. An ohmmeter wouldn't show it but an inductance bridge did.
>

Ouch! Still, shorted turn or not, the chopper shouldn't put more
current through the winding than it is programmed to, should it?

You do have an excellent point about ohm meters. Mine is useless for
low-resistance stepper coils.

I agree though that a 'free' motor must be weighed against the time
invested and the risk to other equipment.