At 05:19 PM 9/20/1999 +0200, you wrote:
>
> Hi all,
> I'm an Italian electronic engineer, and they ask me if it is possible have
> information on rotation of a motor without using an optical encoder!! I have
> already made the project of controlling a motor in PWM with PIC16C62 and with
> the encoder, but now I would like to eliminate the encoder. Is anybody out
> there that have experience with this and can help me???



Marco (that is what they call you, no?  I have a student Gianmarco, he insists
on Marco - perhaps that is USA version).

If you have very good ADC, you can watch the inrush currents on your FETs.  At
first I recommend you plot current vs. position of the armature.  After you do
this some time, you will actually be able to do "timing" of the motor to adjust
to the load, which eliminating the optical or hall sensors.

You are using a brushless motor, right?

Andy

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Andy Kunz               Life is what we do to prepare for Eternity
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andy@rc-hydros.com      http://www.rc-hydros.com     - Race Boats
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