Re: .9 deg/step motor

--- In CAD_CAM_EDM_DRO@y..., "jeffdavis516" <cadman@p...> wrote:

> --- In CAD_CAM_EDM_DRO@y..., Jon Elson <elson@p...> wrote:
> > jeffdavis516 wrote:
> >
> > > Does anyone know why a Vextra 8 wire .9 deg per step stepper

motor

> > > would not work correctly with a bipolar driver? I have tried

this

> > > motor with Dan Mauch's 2 Amp driver and it only goes back and
> forth
> > > when I jog the axis. I know that the driver works because I
> tried a
> > > normal 1.8 deg per step motor and that stepper works fine.
> >
> > Are you absolutely sure that you have to coils wired correctly?

if

> you
> > have them wired up to the wrong phases, it will not move properly.
> > You might start with just half of the coils, and see which ones

make

> > it work right. If you have it wired either in series or parallel
> with
> > just one of the windings backwards, it nullifies the flux for that
> > winding, and the motor will behave just as you describe.
> >
> > Jon
>
> Hi Jon,
>
> Sorry it took me so long to get back with you. I was able to get

the

> motor to run correctly if as you say I only use two of the four
> phases. If I use phase A and B or C and D but I can't seem to make
> the motor work when I try to combine all four phases. I have tried
> series and parallel using Mariss wiring diagram PDF file to no
> avail. I will keep looking, maybe I did something wrong. Servos

are

> so much easier. :)

Have you got the manufacturer's wiring diagram of the motor? The
coils need to be connected in pairs - the two "A" coils connected
together, and the two "B" coils - not one "A" and one "B". For series
wiring, you need to wire the end of the first "A" coil to the start
of the second "A" coil, and same for "B"; for paralell, wire the
pairs start to start & end to end.

If you get one of the coils reversed, or don't pair them correctly,
the result is that the effect of the coils cancel each other out -
you get humming/buzzing (and heating!) but no useful movement.

Regards,
Tony