Summary

Over 60 percent of electricity in the United States is consumed by electric motor drive systems. Generally, a motor drive system consists of several components; a power supply, controls, the electric motor and the mechanical transmission system. The function of an electric motor is to convert electric energy into mechanical work. During the conversion the only power consumed by the electric motor is the energy losses within the motor. Since the motor losses are in the range of 5-30% of the input power, it is important to consider the total system of which the motor is a part.

This chapter deals mostly with electric motor drive systems and provides practical methods for managing motors.

One of the "MotorManager" methods is the Motor Performance Management Process (MPMP) which effectively evaluates the performance of existing motors and identifies opportunities to link them to organizational goals. It is a primary tool to evaluate, measure and manage motors and a logical, systematic, structured approach in reducing energy waste, fundamental to efficiency in a competitive market. With minor changes, this process can be used to evaluate other electrical and mechanical equipment.

Considerable attention must be paid to the efficiencies of all electric equipment being purchased today. This is true not only for motors but for transformers of all types and other electrical devices.

To guard against the waste of electrical energy, manufacturers of dry type transformers are designing them with lower than normal conductor and total losses. The reduction in these losses also lowers the temperature rise of the transformer resulting in improved life expectancies as well as a reduction in the air conditioning requirements.

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