A new method of condition monitoring on electrical contact endurance of power switch

Prediction of the remaining electrical endurance of a power switch is important for the reliable performance of power switches. The erosion of contact material is one of the most important indexes for the electrical life of a contact. Previous methods of contact material life prediction are introduced. They mainly consider the relationship between erosion volume and current amplitude. A new idea is presented to diagnose the life of electrode material from the waveform characteristics of the make and break currents. LabVIEW is used to sample and store the current and voltage signals. Current waveforms, break/make current arc duration and contact resistance are discussed. As a result, the occurrence probability of fluctuating phenomena of the break current, contact resistance and make arc duration change with the number of contact operations. The break arc duration is determined by the break current.