fa عمومى General پژوهشي Research In this paper, some deficiencies of previously conducted studies are pointed out. These are including unreliability, dependent to motor and bearing specifications, lack of precision, drawbacks of experimental tests and etc. Here some important works will be reviewed. The proposed method which is based on wavelet decomposition and tracing the trend of statistical features variations, has overcame most of these deficiencies. Experimental results validated the proposed method. Finally, an approach to enhance detectability and precision in realistic industrial applications which is based on comparing power factor and temperature of tested and industrial application cases, will be presented. Mechanical fault, Single point defect (SD), Distributed defect (DD), Wavelet decomposition, Trend of variation 48 58 http://ijrare.iust.ac.ir/browse.php?a_code=A-10-25-16&slc_lang=fa&sid=1 Seyed Javad Hoseini 180031947532846001602 180031947532846001602 Yes Student of Electrical Railway Engineering, Iran University of Science and Technology, Student of Electrical Railway Engineering, Iran University of Science and Technology, Seyed Mohammad Mosavi Gazafroudi 180031947532846001603 180031947532846001603 No Iran University of Science and Technology/School of Railway Engineering Iran University of Science and Technology/School of Railway Engineering