Patent ID: 6211588
Filing Date: 2001-04-03
Classification: G01D,H02K

Abstract:
A brushless electromotor comprising:a rotor having a permanently magnetized propulsion magnetization zone with at least one pair of magnetic poles,a stationary coil assembly with at least one stator coil, said rotor being rotationally movable by magnetic fields of said at least one stator coil, said rotor having a permanently magnetized measuring magnetization zone; anda sensor disposed in the range of the magnetic field of said measuring magnetization zone, said sensor comprising an arrangement of at least five field-sensitive elements which are sensitive to the magnetic field and are integrated on a semiconductor chip in a row and are each coupled to circuitry on said semiconductor chip, with at least four of said field-sensitive elements covering a period of the measuring magnetization and with at least one of said field-sensitive elements being a redundant field-sensitive element arranged outside said period of the measuring magnetization, and in which said at least five field-sensitive elements cover more than one period of the measuring magnetization, so that a position of the rotor can be determined with high precision from an output signal of said field-sensitive elements, which is generated by the action of the magnetic field of the measuring magnetization zone, by numeric correlation of the measuring signals with a predetermined reference curve corresponding to one or several period(s), wherein a total number of said field-sensitive elements is equal to an integral power of two plus at least 1 redundant field-sensitive element and wherein a number of said redundant field-sensitive elements is from 10% to 50% of said integral power of two.