B.L. Wilson, Oil Dynamics Inc.
An electric motor is similar in some respects to a resistor in that its power rating is a function of the maximum operating temperature of the materials. In electrical apparatus, as far as temperature is concerned, it is permissible to overload the device as long as the safe operating temperature is not exceeded (Ref 1). The temperature of the device is a function of the temperature of its environment and its ability to transfer heat to its surroundings. To be accurate, the horsepower rating of an ESP motor should take this into account. This paper reviews the major factors controlling the generation and the dissipation of energy in a ESP motor and presents a work sheet for approximating the maximum well temperature an ESP motor for acceptable run life.