Re: DC motor controller - CW ?

--- In CAD_CAM_EDM_DRO@yahoogroups.com, "John Hansford" <kz1927@...>
wrote:

>
> Hi Dave,Ron,
>
> Pictures...
> http://www.flickr.com/photos/26361144@N00/
>
> I took the CW to mean the nut would probably fly off if it ran
> the other way. I opened it ...Nothing flew apart.
>
> What's the Bad news...How _BAD_ could they be as servos?
>
> I wouldn't have noticed the very slight cogging if I weren't
> trying to find it.
>
>
> John

Hi John,

Look at your picture 02. it shows the end of the shaft, 17mm, as
well as a 1/2-13 left hand thread.

what the treadmill used to have, is a large cast iron pulley with a
multi grouve belt. the pulley was small, probably under 1-1/2" dia,
but the flywheel was large, 7 inches or so, and cast iron.

My point was, that if you ran the motor in reverse, the flywheel would
unscrew. Once you use the 17mm shaft instead of the threaded part,
the problem goes away.

Dave

>
>
>
> --- In CAD_CAM_EDM_DRO@yahoogroups.com, "turbulatordude"
> <dave_mucha@> wrote:
> >
> > --- In CAD_CAM_EDM_DRO@yahoogroups.com, R Rogers <rogersmach@> wrote:
> > >
> > > John,
> > >
> > > See the "CW" for rotation on the motor tag? That means it's
> > intended to spin only one direction. Possibly the brushes are mounted
> > angular or offset to the shaft allowing only one direction of
> > rotation. If thats the case it will not work, for long anyway.
> >
> >
> > I think the CW could mean one of two things. As you mentioned, the
> > burshes are not mounted perfectly symetrical, but rather optimized so
> > spinning on one directin is more efficent or powerful, or some such.
> >
> > The would mean the brushes are not dead-on-balls-accurate (an industry
> > term) 180.00 degres.
> >
> > The other possibility is that the thread on the screw is such that if
> > the motor spun the opposite way, the pulley would just spin off.
> >
> > Since these are custom motors, the label could reflect either of the
> > above.
> >
> > Testing would show the differences.
> >
> > Dave
> >
>