Experimental testing and theoretical analysis of phenomena which appear in induction motors supplied from inverters indicated that in rotors appears shaft voltage so bearing currents can appear too. However question not completely explained was problem of qualitative and quantitative affecting on raceways bearings condition of induction motors supply from PWM inverters. In order to resolve this question performed following experiment: six new induction motors of the same type supply of following way: - two motors supply directly from mains; - two motors supply from PWM inverter; - two motors supply from PWM inverters but the shaft motors were grounding using the brushes. Past one year of motors work bearing were cutting in order to make analysis of raceways bearings condition. The results of experiment were following: " The surfaces of raceways bearings of motors supply from main were smooth and shine, were not damages." The surfaces of raceways bearings of motors supply from inverter but the shaft motors were grounding using the brushes were smooth and shine too. " However on the surfaces of raceways bearings of motors supply from inverter found a traces of acting of bearing currents in the form of frostings and spark tracks. These damages were not big, they were good seeing on the optical increase. The photo below presents the example of this damage. In the paper are presented the results of experiments and discussed reasons and conditions of created damages on surfaces of induction motors bearings supplied from inverters.