Rotor hot spot detection and resolution in large oil and gas industry motors

Several motors are declared expendable every year due to inaccurate diagnosis or unresolved high vibration. From experience, the cause of these motors being removed from service is mainly due to hot spots on the rotor, which eventually causes this excessive vibration. Accordingly, this paper will introduce several maintenance testing measures when dealing with Induction Motor rotors impacted by such hot spots. Even though Induction Motors are considered the workhorse of modern industry, and their rotors being very reliable in terms of their design and average life, the hot spots will cause a rotor bow phenomena. In the Oil and Gas industry, a rotor bow cannot be tolerated, since it could lead to extended downtime, and associated production loss. Industrial plants must safe guard against such conditions by developing their plant engineers´ technical knowledge, which would include basic information about the symptoms and causes of the rotor bowing phenomenon. This paper will also detail a testing measure applied at a large oil and gas company for identifying and attempting to resolve rotor bows due to hot spots.