An accurate low-cost method for determining electric motors´ efficiency for the purpose of plant energy management

As the cost of energy increases it is increasingly more important to remove inefficient motors from operation. The first step toward achieving this goal is to estimate accurately the existing motors´ efficiencies to determine how much saving will be achieved by using more efficient motors. The problem with estimating the efficiency of motors in the field is the practicality and cost associated with measuring the output power. This paper describes the results of a very-low-cost and accurate method for determining the motor efficiency without the need for removing the motors and without the need for measuring the output power or torque. Test results indicate that the novel method has an accuracy of over 99%. As a result of the high accuracy it is possible to estimate the potential savings with great confidence.