Electrical Generator

Electric generator is a device which is used to generate electricity. It is a device which converts mechanical energy into electrical energy. Whereas the reverse conversion of the electrical energy into the mechanical energy is done by motor; the electric generator and motors have several similarities.

The heart of the central power system is the electric generator. In principle, a generator is a loop of wire rotating in a magnetic field. The principle of the generator was discovered in 1831 by famed British scientist Michael Faraday. He found that as the loop of wire cut across the field lines of the magnet, electric current began to flow in the wire. If the loop of wire was rotated continuously, a continuous flow of current would result.

The discovery of this simple principle eventually led to the effective harnessing of electromagnetic en­ergy (+) and to a radically changed world. The loop of wire rotating in the magnetic field has evolved into the huge electric generators that now produce electricity for entire cities. Virtually all central station power plants produce alternating current (AC). As the loop of wire rotates in the magnetic field it goes through a complete circle, halfway through each rotation the polarity of the current reverses and the current flows in the opposite direction. Thus the current is continually fluctuating back and forth. If the loop makes a complete rotation 60 times in one second, it is producing 60 cycle AC current. This AC current is the one most commonly supplied in the United States. While direct current (DC) could be supplied by making a few engineering changes in the generator, AC has been found to be far more practical for high-voltage, long-distance transmission. A particularly important point is that AC voltage can easily be increased or de­creased through the use of transformers. This flex­ibility allows the power company to adjust voltages to the users' needs.

Questionnaire:

• What is electrical generator? Explain.