Electric motor is the machine reserved to transform electrical energy into mechanical energy, kinetic energy. In the field of industrial drives, it is estimated that 70 to 80% of the electric energy consumed is transformed into mechanical energy by electric motors. Considering an average yield of 80%, about 20% of industrial electricity is transformed into losses in the engines.
According to the type of power source sfh40a carter the electric motors can be divided into motors of direct and alternating current.
DC motors are known for their precise speed control. They are higher cost motors and need a direct current source, or a device that converts ordinary alternating current into continuous. AC motors are the most commonly used, because the distribution of electrical energy is usually done in alternating current. It is estimated that 90% of the motors manufactured are squirrel cage induction motors.
In the selection of the engine several factors will be decisive and the importance of these factors will depend on the use to which the engine will be subjected and the possibilities of the investor as well as the power supply, environmental conditions, load requirements and conditions of service, consumption and maintenance.