Study On The Influence Of Ambient Temperature On The Protection Characteristics Of Hydraulic Electromagnetic Release

Hydraulic electromagnetic circuit breaker is one of our most commonly used low voltage electrical appliances.It uses hydraulic electromagnetic release as the core component.Due to its good protection performance,wide temperature range and low power consumption,it is especially suitable for overload protection and short circuit protection of communication equipment,railway signal equipment and various automatic terminal equipment.The action time of the hydraulic electromagnetic release is determined by the interaction of electromagnetic attraction,spring force and damping force.Although the performance of methyl silicone oil used in the hydraulic electromagnetic release is relatively stable,it has been found that when the ambient temperature changes,the tripping time of the circuit breaker changes greatly,and the change is more obvious under low temperature conditions.Based on this,the influence of ambient temperature on the protection characteristics of hydraulic electromagnetic release is proposed.In this paper,the transient thermal analysis of the electromagnetic system of the hydraulic electromagnetic release was carried out in cold and hot state;the viscosity curve of the damping fluid was fitted,and the damping force of the iron core in the delay tube was analyzed;the dynamics simulation was carried out and compared with the measured results.The influence of ambient temperature on its protection characteristics was analyzed.Firstly,the three-dimensional model of the hydraulic electromagnetic release electromagnetic system was built by Pro/E software,and it was imported into ANSYS Workbench for the transient thermal analysis of the electromagnetic part of the hydraulic electromagnetic release in the hot and cold state.At the same time,the heat generation and heat dissipation of the model with temperature were considered The temperature field and temperature time curves of various parts under different ambient temperature and different currents were obtained,and the influence of ambient temperature on the temperature of the damping fluid was obtained.Real-time measurement of the temperature of the coil part of the tripper when different currents were applied,which verified the correctness of the transient thermal simulation results.Then,the viscosity temperature characteristics of the damping fluid were measured and the viscosity temperature curve was fitted.Analyze and determine the viscosity temperature equation of the damping fluid used in the model to correlate the temperature of the damping fluid with the viscosity.The delay tube model was established and the model was simulated in the FLUENT software for the different viscosity at different temperatures.The damping force at each viscosity was simulated.Finally,the data obtained in ANSYS Workbench and FLUENT were embedded into the multi-body dynamics simulation software ADAMS to simulate the protection characteristics of the hydraulic electromagnetic release,and the action time was obtained when the ambient temperature was different and the current was different.The simulation curve was compared with the actual measurement curve to verify the correctness of the simulation and analyze the cause of the error.According to the analysis,the influence of the ambient temperature on the protection characteristics of the hydraulic electromagnetic release was obtained,and the feasible optimization direction was proposed.The research in this paper provides a basis and direction for optimizing the overload protection characteristics of hydraulic electromagnetic circuit breakers.At the same time,it has important reference value for ensuring the reliability of circuit breaker products and the maintenance of terminal equipment in high and low temperature environments.