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

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