A Method for Calculating and Realising the Dynamic Characteristics of an Electromagnetic Contactor

A contactor is a low-voltage switchgear device widely used in the power system. This study provides a method for the calculation and implementation of the dynamic characteristics of contactors through self-developed manual programming. The computation is divided into two calculations: the current and the motion. In the current calculation, the input parameters include the voltage waveform and other necessary parameters of the main circuit. The program then calculates and outputs the magnitude of the current at each time point; The motion calculation program is used to determine the position of the contactor's moving iron core at each time step by iterating the position and velocity. Combining the current results, the electromagnetic force acting on the moving iron core is calculated, and displacement and velocity are determined and outputted. Through experimental measurements, the start-up time and closing time of the moving iron core in both experimental and simulated scenarios differed by less than 5%, which falls within an acceptable range. Therefore, employing our method as a general numerical computation method for analyzing the dynamic characteristics of contactors is feasible.