The Thermal Analysis Of The Miniature Circuit Breaker DZ47-63C1

As a king of terminal protection electrical components for low voltage power supply anddistribution network, the miniature circuit breaker breaking ability is directly related to thesecurity of electrical appliances and equipments. Long time working, mechanical and dielectricstrength of miniature circuit breaker internal metal and insulation materials decreased, and theminiature circuit breaker breaking ability degraded. At the same time, degradation of metal partsattribute parameters,such as resistivity, density, specific heat capacity, so that the thermal effectwith same work current changed. Therefore, it is significant to analyze the key metalliccomponents of miniature circuit breaker.First of all, energy loss of the miniature circuit breaker contact mechanism was studied.Three-dimensional model of contact mechanism was established in Ansoft software, and thesimulation mathematical model was given. The thermal simulation of contact mechanism onstate and breaking process was based on measured current. Considering the eddy current loss, thevalue of energy loss and the distribution of power loss of the contact mechanism in the on-statewas calculated. Considering the case of arcing, the value of the energy loss of the contactmechanism in breaking process was calculated.Secondly, energy loss of the miniature circuit breaker electromagnetic tripping mechanismwas studied. Three-dimensional model of electromagnetic tripping mechanism was established inAnsoft software, and the simulation mathematical model was given. The thermal simulation ofelectromagnetic tripping mechanism on state and breaking process was based on measuredcurrent, getting the value of energy loss of the coil and static and dynamic core.Finally, simulation research on electrical-thermal-structure was done in bimetal mechanism ofminiature circuit breaker. Three-dimensional model of bimetal mechanism was established inAnsys software, and the simulation mathematical model of electrical-thermal and thermal-structure was given. The electrical-thermal-structure coupling simulation of bimetal was basedon measured current, getting the distribution of temperature, stress,displacement and the value ofenergy loss.The excitation source of miniature circuit breaker on-state and breaking process arerespectively the working current and breaking current. The excitation current formula by themeasured current time series were obtained by MATLAB. The current level related to1-11A,atotal of11current rating.