Patent ID: 6642710
Filing Date: 2003-11-04
Classification: F15B,G01B,G01D

Abstract:
A position sensor comprising:an excitation winding which, when energised, is operable for generating an electromagnetic field; a sensor winding electromagnetically coupled to said excitation winding, for sensing electromagnetic fields; a compensation winding electromagnetically coupled to said excitation winding; and an electromagnetic field modifying member electromagnetically coupled to said excitation winding for modifying the electromagnetic field generated by said excitation winding; wherein said field modifying member and said windings are relatively moveable along a measurement direction between first and second positions and are arranged (i) so that the electromagnetic coupling between said excitation winding and said sensor winding varies as a function of the relative position of said field modifying member and said windings between said first and second positions; and (ii) so that the electromagnetic coupling between said excitation winding and said compensation winding does not vary with said relative position between said first and second positions, whereby a signal obtained from said compensation winding can be used to provide compensation for variations in the signal output from said sensor winding which are not caused by said relative position.