A Study of the Effect of Aging on the Operation of Switching Devices

An experimental study was conducted to determine whether equipment aging affects the vulnerability of electric switching devices to malfunction caused by vibratory stresses in the range of seismic frequencies and acceleration amplitudes. The study included a vibration test before and after a program of accelerated aging designed to simulate forty years of service in areas outside the containment of a nuclear power generating station. Gamma irradiation, thermal aging, electrical/mechanical cycling and simulation of operating basis earth- quakes were included in the program of accelerated aging. Malfunction was defined as spurious opening or closing of contacts for times in excess of 1 ms during the vibration tests.