Energy Conservation Model for Electromechanical Transient Characteristics of Electromagnetic Actuators

Fault diagnosis and bounce reduction of electromagnetic actuators require one to obtain the electromechanical transient characteristics (ETCs) in real-time. ETCs can be measured by sensors, but due to their large size and intrusiveness, the approach has its limitations. Acquiring ETCs through finite element method (FEM) could be an alternative, except that FEM is known to be time consuming. In contrast, real-time measurement of coil current is not subjected to these restrictions, yet, it has not been properly utilized for calculating ETCs. In this regard, this paper analyzes the source of the armature kinetic energy, and thus proposes a model based on energy conservation (ECM), describing the relationship between the mechanical and electrical characteristics. Based on the model, ETCs can be calculated from coil current, moving part mass, and the static counterforce. To exemplify the effectiveness of the procedure, an electromagnetic contactor is considered, and the results obtained using the ECM are found fairly consistent with that obtained using sensors. The merit of the proposed ECM lies in its non-intrusive nature and its ability to circumvent the time-consuming FEM in calculating ETCs.