Rotor angle detection via shaft iron remanence for the balancing process of small rotors

A magneto-resistive sensor for measuring the rotor position angle is introduced, which is based on the remanence of the ferromagnetic rotor shaft. Based on a mathematical model of the remanence field, a sensor concept for rotor positioning is developed. Several magnetization methods for obtaining a dipole field are discussed and were tested. A sensor prototype SR70 of company SchenckRotec^reg, Darmstadt/Germany, is presented, showing that an accuracy of 1deg (mechanical) for rotor positioning is possible, which allows the use of the sensor for the balancing process.