Discussion on terminal voltage waveform at detection of poor contact of low voltage switch by ultrasonic wave method

Abstract

We have proposed a detection method of poor contact of the low voltage switch by an ultrasonic wave. In this paper, poor contact was artificially made putting dried grass, cherry tree, flour, and alumina, between two terminals of a model switch, and the ultrasonic wave was applied under the current flowing by the maximum 5A. From the change of magnitude and waveform of the terminal voltage, it was shown that the contact state of switch can be judged.