Analysis of Electrical Life Distribution Characteristics of AC Contactor Based on Performance Degradation

Electrical life is an important performance indicator of ac contactor, and it is influenced by various factors, among which the most important one is arc erosion caused by arc current. This paper proposes a general contact erosion model based on arcing phase angle to simulate the electrical life distribution characteristics of ac contactor under random breaking operations. For the same type of ac contactor, different individuals have different electrical life due to the manufacturing dispersion, so the normal distribution is utilized to simulate the manufacturing dispersion under $3\sigma $ standard. The simulation results show that the electrical life distribution is closely related to the manufacturing dispersion degree. When the dispersion degree of manufacturing processes is relatively low, the electrical life obeys three-parameter Weibull distribution. Otherwise, the electrical life of contactors obeys normal distribution. Finally, the electrical life test is performed, and the test results are consistent with the theoretical analysis results. The abovementioned conclusion provides theoretical foundation for the reliability evaluation and experimental study of ac contactor.