Method for monitoring the condition of the motor winding insulation

Abstract

The paper presents some results of the investigation of an induction motor stator winding insulation leakage currents which are generated by rectangular voltage pulses with frequencies of 100–2000 Hz. The authors consider the possibility of recording the leakage current parameters and the dependence of these parameters on the amplitude and frequency of the voltage pulses with the aim of using this information to monitor the state of isolation. It is shown that the proposed way makes it is possible to obtain relatively large values of leakage currents which simplifies the operation with them. However, to reliably determine the amplitude of the leakage current peaks, a relatively long measurement period with a large number of transmitted pulses is necessary. Otherwise, the equipment is required that provides a sufficiently high resolution (sample time of the order of 10(1e−6) seconds or less).