Simulation study on arc motion process of 38 A low-voltage AC contactor under AC-4 conditions

In the process of breaking an AC contactor, the ablation of the contact by the arc current is an important factor affecting its electrical life, so the evolution of arc shape in the arc extinguishing chamber has an important influence on its breaking performance. To explore the influence of arc motion characteristics on its breaking characteristics, based on the theory of magnetohydrodynamics and considering the contact motion process, a three-dimensional air arc simulation model is established for the arc extinguishing chamber of an AC contactor with a fixed current of 38 A and the arc motion characteristics of the arc during breaking are analyzed. To verify the accuracy of the simulation model, a test platform was built. Under the same breaking conditions, the arc shape, arc voltage, and arc current were measured, and the experimental results were consistent with the simulation results. On this basis, an optimization scheme of the arc extinguishing component is proposed and its influence on the arc motion process is analyzed.