Re: Specs on Sigma Stepper for Series I Bridgeport?

Forgot to mention: I'm running about 60vdc -65vdc

--- In CAD_CAM_EDM_DRO@yahoogroups.com, "Lee Studley"
<indigo_red@q...> wrote:

> Hi Mike,]
> Like Ray says 80v. For steppers, you can overdrive the voltage

rating

> ( more of a continous DC rating really ) by 20x or more, which is a
> common practive to improve the slew rate of the coils. This means

you

> pulse the voltage way up to bring the current up to a limit as
> quickly a possible.
> Your 53vdc supply will be perfect as it gives headroom for
> powersupply voltage into the geckos which can pump up if the

steppers

> coast and act like generators into the supply.
>
> You are lucky, most have to go thru hoops to derive a usable supply
> when using the original transformers etc. My mill used 160vdc into

the

> steppers, then back it off to about 12vdc holding once the current
> limit was reached.
>
> I got these specs somewhere and they may be similar to your stepper:
> Sigma Instruments 21-4266D200-F022
> specs as follows
> 8 leads
> Torque at 50 SPS 910 oz/in bipolar, 20% less for unipolar.
> Holding torque 1100 oz/in, 20% less for unipolar.
> Detent torque 38 oz/in.
> Phase current amps unipolar 9.0, Bipolar 12.7
> Phase restance .21 ohm.
> Phase inductance 1.6mH.
> Rotor inertia 37.1 oz-in squared.
> Weight 19 lbs.
> series 21 = High speed, high torque thru 4500 rpm.
> 4266 = 4.2" dia and 6.6" long 2 stack rotor.
> 200 steps per rev.
>
>
>
>
>
>
>
>
> --- In CAD_CAM_EDM_DRO@yahoogroups.com, "Mike Mueller"
> <mueller914@y...> wrote:
> > my concern is whether or not the Sigmas require over 13.25vdc, if
> so, then the powersupply is not of high enough voltage (powersupply
> to be at a minimum 4X of the motor) unless I read the manual

wrong ...

> >
> >
> > Mike
> >
> >
> >
> > --- In CAD_CAM_EDM_DRO@yahoogroups.com, "Raymond Heckert"
> <jnr@a...> wrote:
> > > My understanding is that the Geckos will handle up to 80 Vdc.
> > >
> > > RayHex
> > >
> > > ----------
> > > > From: Mike Mueller <mueller914@y...>
> > > >
> > > > thanks !!!
> > > >
> > > > do you know the voltage for the sigma motors? my powersupply

is

> 53vdc,
> > > not too sure if the G201 will be happy at that voltage.
> > > >
> > > > thanks again,
> > > >
> > > > Mike