Correlation between arcing phenomena and electromagnetic noise of opening electric contacts

The authors observed the electromagnetic noise and surface change for a Cu-C electric contact as a simulation model of a commutator motor. In case of Cu-C (anode-cathode), the duration of sporadic burst noise generates from arc discharge. The patterns of the burst noise at the start of the arc are classified into three types, and the pattern of surface change corresponds to each pattern. When burst noise duration increases, the melted area has a wide distribution on the electrode surfaces and the authors have found a correlation between burst noise and the electrode surface area. From these results, the authors proposed a method of noise control by controlling the melted area and showed a fundamental noise control technique by electrode design with consideration of the electrode form.