异步电动机过负荷保护模型的研究

Study on the Model of Asynchronous Motor Overload Protection

本文在分析电动机传统的反时限过负荷保护的基础上,根据导体中流过电流时的发热、散热微分方程得到了累加定子电流的反时限过负荷保护动作方程,经简化后得到累加定子电流的实用的反时限特性递推公式。该递推公式真实地反映了异步电动机过负荷时的发热情况,体现了温升越高散热越快的散热状态。

Based on analyzing the traditional inverse time-lag overloading protection of motors,an inverse time-lag operating equation with accumulating stator current is achieved in this paper,according to the differential equation of the heating and cooling while the current flows into the conductor. Then the equation is further simplified to recurrence formula, which represents the thermal condition of the induction motor really, and reflects that the higher temperature rises,the more rapidly the motor cools.