Electrical Drives

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Electric drives are defined as a form of machine equipment designed to convert electrical energy to mechanical energy and provide electrical control of the process. In very simple words, the system which controls the motion of electric motor is called electric drives.

The first electric drive was devised in Russia in 1838 when B.S. Lakobi tested a DC electric motor supplied from a storage battery and used it to drive a screw propeller on a boat. However, adoption of electric drive was delayed for a lack of reliable source of electric energy. Even after the development of industrial DC generator in 1870, efforts to introduce the electric drive were spontaneous and without practical significance.Today a substantial percentage of the electric drives in operation are used in transportation.

Electric drives comprises of

Source - Electric energy source. It may be single phase or three phase. Single phase supply for single phase motor and three phase supply for three phase motor.

Load - It is usually a machinery designed to accomplish a given task such driving a centrifugal pump.

Motor - It is a device which converts electrical energy to mechanical energy.

Power Modulator - It modulates power from source to motor in a manner that motor is imparted or improve speed torque characteristics required by the load.

Control unit - Provides control for power modulator.

Input command signal - Adjust the operating point of drive from input to control unit.

Sensing unit - Perform sensing of drive parameters such as motor voltage, current and speed required either for protection or for closed loop operation.