Investigation of the degradation process and failure mechanisms of AC contactor in the electrical endurance experiment

The longer electrical lifetime and higher reliability of AC contactors are forever demanded for industrial customers. It is known the occurred failure events of contactors are mainly caused by the long-term arc erosion of contacts. However, the determination of sensitive parameters and associated degradation process are still hot topics in this field. In this work, the waveforms of contact voltage, contact current and coil current of AC contactor were recorded explicitly in the electrical endurance experiments. The degradation of electrical performance parameters, including arc energy and opening time, are extracted from the recorded waveforms. In addition, the effects of opening time difference among three individual phases on the electrical performance and arc erosion were discussed. The method could be beneficial to accurately evaluate the health status of AC contactor and predict the residual usage lifetime.