[Robotgroup] Stepper Motor Help..?

[Nick Pietraniec]

The cd rom drive is a good idea...  The problem with ramping up the
speed with gears is that you'll have to slow down the stepper motor even
more to provide the necessary strength to move those gears.  you could
get a lot of torque out of low rpms though, so it might be worth
checking out...  However, the motion could be a little jerky

On Wed, 2006-12-06 at 12:37 -0600, Marc Emerson wrote:
> Maybe try a motor out of a cd rom drive. They are 3 phase motors and
> have driver chips for controlling the rpm's. rpm feedback is provided by
> hall effect transistors.
> 
> 
> -----Original Message-----
> From: robotgroup-bounces at puremagic.com
> [mailto:robotgroup-bounces at puremagic.com] On Behalf Of Vern Graner
> Sent: Wednesday, December 06, 2006 12:30 PM
> To: Austin Robotgroup Mailing List
> Subject: Re: [Robotgroup] Stepper Motor Help..?
> 
> Nick Pietraniec wrote:
> > I'd be really surprised if you could get that kind of speed out of a
> > stepper motor, especially if it's driving the platter.  Torque on a
> > stepper motor will drop down to almost nothing when they start going
> > fast.  Based on my understanding of stepper motors and my (limited)
> > experience, if you got 300rpms, well, that's probably pretty "fast"
> 
> Some googling has reveled that, for the most part, about 300 rpm is tops
> for stepper RPM w/o going to extreme measures... I wonder if I could
> just use a gear train to "ramp it up"...?
> 
> The new bracket design is much lighter so maybe we could just use a 4x1
> gear set to bump from 250 to 1000 rpm?
> 
> Hmm.. time to talk to the amazing Rick!! :D
> 
> Vern
>