Re: Frozen stepper motor shaft

A motor that has a shorted turn in a winding will also act like
a 'frozen shaft'. Usually an Ohmmeter will not help; if a winding has
100 turns of wire and only a single turn is shorted, the drop in
resistance will be only 1%. The only give-away is the very high
torque required to turn it.

Mariss


--- In CAD_CAM_EDM_DRO@yahoogroups.com, "iseechipsfly"
<menglish@s...> wrote:

>
> Thanks guys for the feedback... Andy, looks like your suspicion of
> corrosion is the culprit. They were stored in their foam containers
> and there was no indication of exterior corrosion. I checked the
> resistance and it was about 3 Ohms lower than the other motors. I
> removed the outer covers (one at a time) and found some mild

pitting

> from the stator windings on the aluminum covers. There is more
> evidence of the corrosion between the stator and the rotor with a
> very light rust color on portions of each. The good news...

initially

> I thought two were frozen... turns out I only have one new paper
> weight.
>
> Again Thanks - Mike
>
>
>
> --- In CAD_CAM_EDM_DRO@yahoogroups.com, "Andy Wander"

<awander@v...>

> wrote:
> >
> > ...I guess if I'm going to be so pedantic I should be
> talking "ounce-force", huh............?
> >
> > I have seen motors that got wet in storage, where water seeped in
> along the shaft, and froze things up. (the ones I saw were not
> steppers, but you never know, right). The corrosion was not

apparent

> on casual inspection, as it was pretty much confined to the part of
> the shaft INSIDE the bearings.
> >
> > Andy Wander
> > Verrex Corporation
> >
> > -----Original Message-----
> > From: CAD_CAM_EDM_DRO@yahoogroups.com
> [mailto:CAD_CAM_EDM_DRO@yahoogroups.com] On Behalf Of Alan Marconett
> > Sent: Saturday, January 21, 2006 9:35 PM
> > To: CAD_CAM_EDM_DRO@yahoogroups.com
> > Subject: Re: [CAD_CAM_EDM_DRO] Frozen stepper motor shaft
> >
> > Hi Andy,
> >
> > I agree that it's not oz divided by inches, but it's not oz MINUS
> inches either! I'll probably be OK when it comes to the

equations.

> Each to his/her own! ;>)
> >
> > The RUST on the shaft/end bells would surely be an indication of

a

> serious problem! The shafts I've seen on steppers seem to be of a
> pretty good steel, I've seldom (if ever?) seen any rust there.

Bent

> shaft, dented end bells (different name?) as others have mentioned,
> would also be serious. But I just took it that they were new/used,
> and might actually be OK (hope so!).
> >
> > Alan KM6VV
> > Déjà Vu!
> >
> >
> >
> > This communication including any attachments, are intended
> > for the exclusive use of the addressee(s) and contains
> > confidential or copyrighted materials. Duplication,
> > distribution or reproduction is strictly prohibited by law
> > without written permission of Verrex
> >
>