Analysis on contact failure of instrument and control switch in nuclear power plant

For understanding the law that the trend of contact resistance follows the changed current, an equipment which was made up of an intelligent multi-function data acquisition, cooperated with PC programs, for measuring contact resistance was developed. The scanning electron microscopy(SEM) and Energy Dispersive Analysis System of X-ray were used to analyse the microstructure of contact. By observing the microcosmic appearance and analysing the component of contact, the failure reasons was confirmed.