摘要：电动机在工农业中有着广泛的应用，因此对其保护技术的研究具有重要的意义。在电动机的各种故障中，最普遍的现象是电动机因过载而被烧毁。因此，为能够真实地、及时地反映出电动机运行时其内部绕组的温度变化情况，使电动机更好地得到保护，本文采用热网络法建立了电动机热网络模型。基于热网络模型，分析了电动机内部各节点的温升分布情况，并为进一步分析电动机内部的局部过热提供了依据，从而提高了电动机保护的精度和可靠度。本文以三相异步电动机为试验样机，根据电动机内部结构和发热源的不同，将电动机的定子铁心、定子槽绕组、定子绕组端部、转子导条和转子铁心五个部分分别作为节点，建立了五阶热网络模型。

关键词：电动机; 热网络模型; 过载保护
Abstract: Electric motor is widely used in industry and agriculture, and therefore the study on motor protection technology has great significance. It is the most common phenomenon among various faults of motor that the motor is damaged caused by overload. In order to reflect the temperature changes of the internal windings truly and timely, a motor thermal network model was built based on the method of thermal network. According to the thermal network model, the temperature of internal nodes was analyzed in detail, which provided the basis for the local overheating analysis of the motor.Thus, the accuracy and reliability of the motor protection were improved. Threephase asynchronous motor was taken as the experimental prototype. According to the internal structure and different heat source of the motor, the motor was divided into five parts as five nodes respectively, which were stator core, stator slot winding, stator end winding, rotor cage and rotor core. As a result, a fifthorder thermal network model was built.

Key words: electric motor; thermal network model; overload protection