APPARATUS AND METHOD FOR REDUCING BEARING CURRENT

摘要

The object of the invention is an apparatus and method for reducing bearing current in an electrical machine. A stator with its magnetic circuit is supported on the frame of the electrical machine, and a rotor with its magnetic circuit is arranged at an air gap away from the stator on an axle shaft supported on the frame of the machine by bearings. The stator of the electrical machine comprises a magnetically conductive yoke (20) and the main magnetic flux of the machine is closed through the stator's magnetic circuit, the air gap and the rotor's magnetic circuit. According to the invention, the machine is fitted with at least one closed suppression winding (40), essentially arranged around the stator (20) of the machine so that the main magnetic flux of the machine goes through the coil ring formed by the suppression winding (40) and the total electromotive force induced by the main flux in the closed suppression winding (40) is essentially zero.