Re: Unipolar or Bipolar?

Hi German,

You are correct. if you can put out 10kHz pulse on a simple drive,
you get 10kHz steps. if you use a microstepping drive, that figure
gets divided by the microstepping rate.

Gecko's are 10, so, you would get 1kHz. Others are half step, 8th
step and so on.

The low amps of your steppers makes your options much wider than if
you had say 3 amps. Then your choices would be much more limited.

Another point is that if you wire your motors in series, you only
need half the current from the drive. If you use a single coil on a
6 wire, or parallel on an 8 wire you need the full volts.

One thing I was considdering was that if you ever want to go up in
power, you will need to either increase voltage or amps. a Voltage
increase can be done if you are not at the peak of your motors
envleople or the available drivers.

amp increases mean new motors. my thought process would then mean
new drives unless you had a high amp drive.

by my estimates, a 30 volt drive for 2.5 amps can handle motors up to
75 watts. a 70 volt drive at 7 amps can handle up to 210 watts. On
my stepups, I am using 5V 1.5 Amp steppers an 1.7V 4.7amp both wired
series for half the amperage. But I am not usig them on a milling
machine.

Dave






--- In CAD_CAM_EDM_DRO@yahoogroups.com, "g_f_bravo_g <factor@f...>"
<factor@f...> wrote:

> Dave,
>
> Many thanks for your response and clarify my concepts about
> unipolar/bipolar.
>
> As understand apply high voltage to the motors with bipolar
> configuration is better than unipolar controller even with the same
> high voltage.
>
> If I use microstepping with bipolar, I obtain smoother response,

but

> what happen with the maximum speed, is same that full step or I am
> wrong?
>
> German
>
> --- In CAD_CAM_EDM_DRO@yahoogroups.com, "turbulatordude
> <davemucha@j...>" <davemucha@j...> wrote:
> > With the high voltage, you would be better served with something
> over
> > 60 volts.
> >
> > The motors themselves are not bi-polar, or uni-polar, only how

you

> > power them makes them bi-polar or uni-polar. Then they are only
> > connected bi-polar or connected, uni-polar.
> >
> > Bi-polar will offer better performance.
> >
> > so that puts you into the chopper, bi-polar, 60-80 volt range.
> > the low amps means you could use quite a few drivers, check the
> > ratings.
> >
> > Microsteping will offer much smoother response and does not cost

a

> > lot more.
> >
> > I think that with the high stepper voltage, you might be better
> with
> > a Gecko, but that is just my opinion.
> >
> > Dave