115 Motor

The origin of the electric motor can be traced back to 1831 when Michael Faraday demonstrated the fundamental principles of electromagnetism. The purpose of an electric motor is to convert electrical energy into mechanical energy.

Electric motors are efficient at converting electric energy into mechanical energy. If the efficiency of an electric motor is 80%, it means that 80% of electrical energy delivered to the motor is directly converted to mechanical energy. The portion used by the motor is the difference between the electrical energy input and mechanical energy output.

A major manufacturer estimates that US annual sales exceed 2 million motors. Table 11.1 lists sales volume by motor horsepower. Only 15% of these sales involve high-efficiency motors.3

Table 11.1 Polyphase induction motors annual sales volume.

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