Development of IoT-Based Device for Nonintrusive Measurement of Rotational Speed of Induction Motors

In this research, the authors developed a compact, portable IoT-based device for measuring the vibration of the electric motors. The vibration signals of an electric motor can be used for the prediction of malfunctions of a motor by utilizing machine learning algorithm. In addition, the developed device is capable of precisely measuring the rotational speed of an induction motor. This paper focuses on the measurement of rotational speed of an induction motor by using the developed IoT-based device. In this paper, the rotational speed measurement principle of the device is theoretical studied by discrete Fourier transform (DFT) of measured magnetic signals and vibration acceleration signals. Moreover, experiments are conducted to evaluate the performance of the device. It is demonstrated that the device can real time measure rotational speed of an induction motor and display the results in an application running on a smartphone. The measurement error of the device is less than 2.3% for wide range measurement of rotational speed of an induction motor. The results prove that a compact, simple to operate, low-cost device is successfully developed for nonintrusive measurement of rotational speed of an induction motor.