The vibration signal during the breaking process of a circuit breaker contains a wealth of mechanical features

so mechanical fault diagnosis of the equipment can be studied by extracting the vibration signal. In this paper

for a 12 kV AC medium-voltage vacuum circuit breaker

its vibration signals in normal and fault conditions are collected by the self-made on-line monitor of circuit breaker. The short-time energy method

the total energy analysis method and the information entropy method are employed to analyze and process the vibration signals. This monitor device can capture characteristic information of vibration event and distinguish normal or fault state

hence it can be taken as a tool for implementation of on-line fault diagnosis technology of circuit breakers.