Re: 8-wire stepper: series is 1/2 the amps.Strange but True

Hi Lee,
Won't series winding (full winding) RESISTANCE be TWICE the amount
of the single coil (1/2 coil), while your series winding INDUCTANCE
be FOUR times that of the single coil (1/2 coil)?

With series winding (full winding), you have twice the number of
turns of wire being energized as half winding, so you use half the
amount of current to acheive the same holding torque.

Jeff
http://www.xylotex.com

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

> Hi,
> I would in my early days have agreed until Mariss gave me new
> insights into motor inductance:
>
> When wiring stepper coils in series, or full winding, the amperage
> is 1/2 the plate rated( I think this plate rating is for a single
> coil energized), this is due to the inductance being twice the
> amount than that of a single or 1/2 coil. Using V=L di/dt and stick
> a fixed dt=1 (1sec) relation in there to simplify the thought
> process, and setting V equal to the fixed motor drive voltage.
> V is proportional to L * di where di is a change in current. So if
> you double the L value( 2coil in series) then di ( or I) had to
> decrease by 1/2 if V is fixed. This relation shows the ability of

an

> inductor to oppose a change in current.
>
> So 1 amp full series, or 2amp single or 1/2 coil.
> Do the experts agree?
> -Lee
>
> --- In CAD_CAM_EDM_DRO@yahoogroups.com, "forumtvm" <forumtvm@y...>
> wrote:
> > "WUKSTA" <gerry@z...> wrote:
> >
> > > After reading all the posts on this subject I am a little
> > confused.
> > > I have three Vexta (Oriental Motor) PK268M-02A steppers that
> will be
> > > driven by Gecko 201 drives. These steppers are 187 in/oz.;
> 2A/phase;
> > > 4.5V; 2.25 ohms/phase; .9 deg; 6 wire motors. If I run these
> motors
> > > "Half Coil" would I run them @ 2amps or 4amps? With my cheap

volt

> > > meter, I get a resistance of 4.8 ohms full coil & 2.5 ohms half
> > coil.
> > >
> > Hi Gerry,
> >
> > I believe it should be 2Amp. Your cheap voltmeter I believe has
> > confirmed that - 4.5V / 2.5 ohm = ~2A
> >
> > Peter