> How are you driving the motor? PIC can't possibly
> deliver enough current to drive it directly. I used
> 12V/1.2A motor in a project and it had so much torque
> that I couldn't stop it with hand.

Use power MOSFETs --- it would be useless to drive a motor directly from a
PIC, and near suicide to drive one of your rating with signal BJTs. To err
on the side of caution, make sure you use 220-ohm resistors in series
between the PIC and the MOSFET gates (since 25 mA is the nominal max current
source for a PIC pin). Alternately, you may want to look into using MOSFET
drivers. Also, if you use different (higher) logic/drive voltages, make sure
you isolate the PIC properly.

Cheers,
Ishaan





> Samo
>
>
> --- CVT-SSS <cvt@CVT-SSS.COM> wrote:
> > Hi folks,
> >
> > May anyone help me on how to increase the torque of
> > an stepper motor ?
> > I am using a six wire unipolar stepper motor,
> > 4.1VDC, 1.8 degree per step
> > 1.1 Amp from SANYO DENKI.
> > I have a program for the pic16f84a, who sends the
> > following sequence pulses:
> >
> > to coil a1: 1000
> > to coil b1: 0010
> > to coil a2: 1001
> > to coil b1: 0100
> >
> > each pulse has 10 mSec and works well, but the
> > stepper motor do not work
> > with load.( mechanically attached to the capacitor
> > axis )
> >
> > I need to use this stepper to control a vaccum
> > capacitor from Jenning Co. to
> > tune a loop antenna
> >
> > In somewhere I read is possible to send a pulse to
> > two coils at same time,
> > but don4t remember whre.
> >
> > regards,
> >
> > Augusto
> >
> > --
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>
>
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