Failure mechanism of high frequency electromechanical horn induced by cyclic intermittent arc behaviour

The high frequency electromagnetic (EM) horn with mechanical contacts is a type of energy transducer. It sounds through its diaphragm, which is excited by the high frequency and pulse electromagnetic excitation. The pulse current generated by the high frequency making/breaking actions of mechanical contacts produces electrical arc produced during the process, which brings huge effect on the reliability and electrical life time of the horn. In this paper, the integrated experiment system was designed for the electrical life time of the high frequency EM horn, by which the degradation process of action current, peak value current, contact resistance and time parameters evolved was analysed. The failure reason and mechanism of the horn was discussed. The conclusions are of great value for further improvement of reliability of the EM horn production.