["Followup-To:" header set to sci.electronics.misc.]
On 2005-11-07, Eric Meurville wrote:
CWatters wrote:

"Eric Meurville" wrote in message
...

Hello,

We are seeking a solution to monitor contactlessly (up to 10-15mm or
more if possible) the position of a small cylindrical rotor (diameter
1.6 mm, length 2 to 4mm) diametrically magnetized spinning up to 300 Hz.
The solution must not be too sensitive to misalignment of rotor and
sensor (e.g. up to +/-45°).

All propositions and comments are welcome.


What's making it spin? Can you monitor that or do you expect some slip?

Modern brushless DC permanant magnet motor controllers monitor the position
of the rotor using unpowered windings as a sensor coil.





The rotor is excited by an external rotating magnetic field generator
composed of a 3-Phi coil and 3 PWM generators.

external to the implantee?

so you have to cancel that field out before you can read its position,
any nearby magnetic materials are going to muddy the water no matter how
finely you tune the sensor.

--

Bye.
Jasen