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Reliability of automotive parts has been one of the most interesting fields in the automotive industry. Especially small DC motor was issued because of the increasing adoption for passengers' safety and convenience. This study was performed to develop the accelerated life test method using Inverse power law model for small DC motors. The failure mode of small DC motor includes brush wear-out. Inverse power law model is applied effectively the electronic components to reduce the testing time and to achieve the accelerating test conditions. Accelerated life testing method was induced to bring on the brush wear-out as increasing voltage of motor. Life distribution of the small DC motor was supposed to follow Weibull distribution and life test time was calculated under the conditions of B₁₀ life and 90% confidence level.

As motors used for automobiles use battery-stored electricity, most motors are of the small-sized DC variety, of which typical failures are primarily classified into brush wear, coil burn-out, and bearing damage. From such failures, it is required to understand the failure mechanism due to the brush wear as it relates to the life of DC motors, as a result of the wearing defects. As the lifespan of DC motors is strongly associated with brush wear and as the effect factors of brush wear relate to several mixed actions, it is necessary to conduct research on the analysis of the effects of such wear processes. This study aims to analyze the main effect factors emerging from a brush wear test of the blower motor, a representative DC motor used in automobiles. The main effect factors of brush wear are associated with both mechanical wear and electrical wear. For examples, there are voltage, current, rotation speed, spring load, and temperature effects on the operational and environmental conditions. This study was intended to examine the effects of these major factors on brush wear through a brush-wearing test for each factor. With an adequate analysis of these effects, the extracted acceleration factors for DC motors may be applied to the development of an accelerated life test method for DC motors.