Measure System Evaluation About Squeal Noise in Deep Groove Ball Bearings of Electric Motors

Companies aspire for leading position through competitive products that meet customer requests. Electrical rotating machines require, in addition to high efficiency, and continuously reduce noise levels to meet customer demands. The origin of the noise present in the motor needs to be known to work on reducing it and consequently increase the machine performance, making the product more reliable for each specific application. Bearing deterioration is the main factor that contribute to mechanical failures in electric motors. The evaluation of bearing behavior through noise and vibration analysis makes it possible to perform improvement studies and even machine intervention to increase its service life. Squeal noise is one of the noise types observed in bearings, characterized by its usually intermittent behavior and by apparent metal-to-metal sliding. A credible measurement system to quantify the desired measurand is a premise for any improvement work. Faced with the exposed, this paper contains the study of three different measurement systems to define which system can quantify the squeal noise in deep groove ball bearings used in induction electric motors. The systems studied are: sound pressure level, acceleration spectrum, and demodulation of acceleration spectrum. The present study evaluates these measurement systems through planned experiments, using the Six Sigma methodology by using Measurement System Analysis tool. These systems are analyzed for measurement stability, discrimination, repeatability, and reproducibility. An empirical noise evaluation is also performed. This enables a comparison between subjective values and results with the different measurement systems studied, helping to define which system best quantifies the squeal noise.