Study on motor over-load protection based on heat accumulation-emission model

This paper analyzes heat accumulation-emission of asynchronous motor,then establishes a dynamic mathematical model by discrete Fourier transform. It can reflect dynamic changes of motor thermal accurately and continuously,so as to prevent thermal rising too high felicitously. Compared with traditional inverse-time protection,the model can reflect heat accumulation caused by load changes more accurately and more acutely. An intelligentized protector using ARM IPC2131 is designed based on the model. A long time on-site operation proves its feasibility.