Embedded system for speed estimation by means of sound analysis in three-phase induction motors

Abstract

Electric motors consume a large portion of the electric power generated. Three-phase induction motors are the most used in industries, for their robustness, reliability and easy operation. They are inserted in the most diverse processes as the main electromotive force. Measuring speed directly on the motor shaft is no trivial task, because it requires time and additional cost due to adaptations of speed transducers to the axis, which causes costly stops to the process in which this motor is inserted. For this reason, manufacturers and research centers around the world have been developing speed estimation methods based on sensorless techniques. The speed measurement in motors can be used for various applications from vector control of the machine to failure analysis. In this work, a new method was developed and installed in an embedded system to estimate the speed in threephase induction motors through the FFT motor sound analysis. This technique proved to be reliable, showing good accuracy in comparison to the measured speed on the shaft, demonstrating the effectiveness of the method and applicability in other areas of technical and scientific relevance such as analysis and prevention of bearing failures or any mechanism involving shaft rotation.