Accelerated life test for identifying potential failure modes and optimizing critical design parameters in a journal bearing

Accelerated life tests (ALT) are useful in identifying potential failure modes of products at the design stage, before they are put to use in practical situations or environments. Early failures have adverse effect on both the image and the market share of the manufacturer. An ALT was carried out to identify failure modes and optimize critical design parameters of a 1/2 hp induction motor used in home appliances. Previous ALTs studies showed early failures in the journal bearings. The journal bearing of the motor is made of alloy bushings lubricated through a window in the bushing. The positioning of the window was found as a critical design parameter that affected proper lubrication, which ultimately determines the life of the motor. The ALT was designed to determine the optimal position of the window that produces the maximum life for the motor. This was done by carrying out tests at higher loads and at different window positions. A Weibull.m MATLAB program was developed and validated with published data to analyze the data in this study. An optimal position for the lubrication window was found based on the ALT test results.