中文摘要：

分析了异步电机在启动、稳态、失电三种运行状态下的转子断条故障情况,根据电机启动过程中故障特征频率的特点,提出一种基于短时分数阶傅里叶变换（STFrFT）的转子故障诊断方法.采用STFrFT对定子启动电流信号进行时频分析,解决了故障信号和工频信号难以分离、不易提取的问题.实验结果表明,该方法不仅能有效检测出故障信号,而且能反映出故障特征频率的变化趋势.

英文摘要：

This paper analyses the rotor broken-bar fault in asynchronous motor under three operating states including start-up,steady-state and power failure.According to the features of fault character-istic frequency during motor starting,a rotor fault diagnosis method is put forward based on short-time fractional Fourier transform (STFrFT).Time-frequency analysis of the stator starting current signal is processed by STFrFT,which solves the problem that fault signal and power frequency signal are difficult to be separated and extracted.Experimental results show that the proposed method can not only detect the fault signal effectively,but also indicate the changing trend of the fault characteris-tic frequency.