Patent ID: 6232739
Filing Date: 2001-05-15
Classification: G01D

Abstract:
An apparatus for determining a position of a rotating member of an electric machine including a target wheel having a plurality of teeth, separated by slots, angularly spaced around a periphery thereof, said target wheel being configured to be mounted to the rotating member, and a sensor assembly proximate said periphery having a plurality of sensors each configured to generate a respective output signal that transitions between first and second states at the passage thereby of each leading and trailing edge of said teeth, and a processing circuit generating a position signal in response to said output signals, characterized in that:each sensor being spaced from an adjacent one of said sensors by a predetermined distance; and,said processing circuit having a first mode of operation wherein a first number of said plurality of output signals are utilized to generate said position signal, said processing circuit further having a second mode of operation wherein a second number of said output signals different from said first number are utilized to generate said position signal, said processing circuit being configured to switch from said first mode to said second mode when said rotating member reaches a first predetermined speed.