Abstract—At present, one of the most effective methods for detecting dangling bars in squirrel-cage rotor windings of induction motors operating under severe starting conditions is the spectral analysis of stator current in a steady-state operation mode. The existing methods of testing in starting modes are not sensitive enough or their study has not been completed, although it is precisely such methods that allow diagnostics of machines that cannot be inspected in the steady-state operation mode. The purpose of this article is to develop a method for monitoring the state of rotor windings in induction motors operating under severe starting conditions based on the stator current in the starting mode, which is an urgent task. The studies were carried out both on digital models of an induction motor, developed in the Ansys software package, and on an experimental stand with a low voltage supplied to a low-voltage motor to increase the duration of its start. Signal processing is performed in the Matlab software package using the short-time Fourier transform. It is shown that only in the presence of a broken rotor bar, the amplitude of the harmonic component of the order coinciding with the number of motor pole pairs sharply increases at the lower side frequency; this indicates the presence of damage. It is shown that the developed technique for monitoring the condition of rotor windings in induction motors operating under severe starting conditions is more sensitive to broken rotor bars than the existing methods; this makes it possible to timely detect damage to rotor windings and prevent sudden failures of induction motors.

摘要-目前，检测在严格启动条件下运行的感应电动机的鼠笼式转子绕组中悬空条的最有效方法之一是在稳态工作模式下对定子电流进行频谱分析。在启动模式下进行测试的现有方法不够灵敏或尚未完成研究，尽管正是这种方法允许对在稳态运行模式下无法检查的机器进行诊断。本文的目的是开发一种方法，该方法基于启动模式下的定子电流来监测在严酷启动条件下运行的感应电动机中转子绕组的状态，这是一项紧迫的任务。这些研究都是在Ansys软件包中开发的感应电动机的数字模型上进行的，并在实验台上向低压电机提供低压，以增加其启动时间。使用短时傅立叶变换在Matlab软件包中执行信号处理。结果表明，只有在转子条断裂的情况下，与电动机极对数相对应的阶次谐波分量的振幅才在下侧频率处急剧增加。这表明存在损坏。结果表明，与现有方法相比，用于监测在严酷启动条件下运行的感应电动机中的转子绕组状况的已开发技术对损坏的转子条更为敏感。这样可以及时发现转子绕组损坏，并防止感应电动机突然故障。