| Overload relay is widely used in overload protection of various motor. Its performancedirectly affects the performance state of the motor. When overload relay works, in order toensure that its maximum temperature does not exceed the allowable limit temperature, andto improve the reliability of the product, it is very necessary to study on the heatingsituations of overload relay under various working conditions. So research on thermalanalysis of overload relay has a very important significance for its safety running.In this paper, typical overload relay JR36-20is taken as the research object. The heatconduction of the thermal bimetal system and the heat convection of the outer surface areconsidered. By use of the finite element software ANSYS, the three-dimensional model ofthe thermal bimetal system is established. The coupling analysis of the thermal-electric-structure is carried out. The temperature distribution, stress distribution and displacementdistribution of the bimetal’s free end are acquired. The results show that the temperatureand the stress are not uniform distribution. The influence of the environment temperatureon the temperature field of thermal bimetal system is studied on. The results show that thetemperature rise of thermal bimetal system changes relatively small within its allowableenvironment temperature range. By experimental method and empirical formulas, thesimulation results are verified. The reasons of error are analyzed to provide basis on thedesign of overload relay. |
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