Date of Graduation


Document Type


Degree Type



Statler College of Engineering and Mineral Resources


Industrial and Managements Systems Engineering

Committee Chair

Bhaskaran Gopalakrishnan.


Energy is an extremely valuable resource which should be used carefully. After realizing this in the 1990's DOE started various energy efficiency measures in order to reduce the energy consumed by US industry. Motors use almost 50 percent of the electricity in the United States. If motor efficiency could be increased then energy consumption could be reduced. There have been efforts to increase motor efficiency over past decade which lead to development of premium efficiency motors. Designed motor efficiency is normally above 90 percent so motors do not waste energy. However, motor efficiency decreases when load factor is less than 50 percent. Therefore measures need to be taken to make the motor sizes properly fit the application load profile so as to improve operational efficiency. Based on plant assessment experience plant personnel have very limited data on motor loading. The decisions concerning motor sizing are usually based on judgment or the slip method. Accurate load determination methods such as input power measurement involve working around high voltages hence have safety issues. These methods are time consuming and expensive. The purpose of this research was to develop a method of sizing electric motors which is simple to use, economical, safe and accurate. This research collected data during fifteen energy assessments conducted at variety of facilities using the motor load monitoring method as well as by using a stroboscope method. A statistical analysis of the data was conducted to determine if a relationship exists between slip method and input power measurement load factors, so that prediction of accurate load factor can be made based on the load factor obtained by slip method. The model was built and validated based on mathematical and electrical engineering principles.