Patent ID: 7511450

Claim:
A method of maintenance for a motor driving system having a frequency converter and a motor, wherein an output power from said frequency converter is applied to motor windings of said motor to drive said motor, said method comprising the steps of: obtaining first characteristics and second characteristics, wherein said first characteristics indicate a relation between a rise time of a voltage to be applied to the motor windings and a value of a voltage at which a partial discharge will not occur between motor windings, and said second characteristics indicate a relation between inductances of reactors provided between the frequency converter and motor and a change in said rise time of the voltage; obtaining, based on the first characteristics, a surge voltage suppressing rise time of a voltage output from the frequency converter is obtained at which the partial discharge is suppressed from being generated between motor windings; obtaining, based on the surge voltage suppressing rise time and the second characteristics, an inductance satisfying the surge voltage suppressing rise time; and arranging a reactor having the obtained inductance between the frequency converter and the motor.