Identifying root causes of failures in small electric motors

Accurate identification of root causes helps not only to prevent reoccurring failures but also the efficacy of the insurance claims settling process. Hence FM Global Research has undertaken a study to identify root causes of failures in small electric motors. The study involves a detailed literature review and the development of the Lightning-induced overvoltages (LIOV) matrix. This matrix was developed to evaluate the damage potential of individual indirect strikes by accounting for strike current magnitude and strike distance. This paper provides guidance to aid in identifying the root causes of motor failure under the categories: 1. Electrical insulation aging, 2. LIOV´s, or 3. Artificial surges.