Partial Anisotropy of Non-Oriented Electrical Steel Sheet as Cause of Shaft Voltage of Induction Motors

Shaft voltage is commonly found in induction motors. Shaft voltages occur in the motor, which is supplied by frequency inverter, but also in motors supplied directly from electrical network. The authors most often deal with occurrence of shaft voltages when supplying by frequency inverter. The literature also contains a lot of knowledge about the causes of shaft voltages, which occur during supplying directly from electrical network. In most cases, electrical or magnetic circuit unbalances due to motor design or shaft eccentricity are discussed as a cause of shaft voltages. Our article deals with the occurrence of shaft voltages due to the asymmetry of the magnetic circuit, which was caused by the partial anisotropy of the sheets, from which the stator and rotor packets are composed. The article also deals with the solution - by removing such magnetic asymmetry and thus induced shaft voltage.