How Does an Electrical Generator Works

Converting Mechanical Power to Electricity

    Generators use the process described above to convert mechanical energy into electricity. The mechanical energy is what turns the shaft upon which the electromagnets are mounted, and there are a variety of sources used to provide this mechanical, turning motion. Most power plants are thermal power plants. These use a source of heat, such as burning fossil fuels or a nuclear reaction, to boil water into steam. The hot jet of steam passes through a turbine, turning its blades and providing a source of mechanical power, which is then transferred to the generator to turn the shaft. Wind turbines capture the kinetic energy of the wind to turn the shaft, whereas hydroelectric plants do the same thing with the energy of moving water. A portable generator does not burn gasoline to boil water in the same way that a thermal power plant does, but instead uses the mechanical power of an internal combustion engine to turn the shaft.


    The Components of an Electric Generator

        Modern electric generators are made up of a spinning rotor, which is generally a circuit made of copper. This rotor spins perpendicular to a magnetic field generated around the rotor. This magnetic field can be generated by either permanent magnets or electromagnets. As the rotor spins relative to the magnetic field, it produces current in accordance with Faraday's law of induction. This current is the source of the electrical energy from the generator. The law of induction states that any changes in a system's magnetic field will create voltage. In terms of the law, the voltage is called electromotive force, which is practically a more descriptive synonym for voltage. The magnetic field changes due to the spinning of the copper circuit in the magnetic field.
    The Rotor's Spin

        In many cases, electrical generators, also called turbines, are built near hydroelectric dams. This is because the dam uses the energy of the flowing water to spin the rotor of the electric generator. Another method of spinning the rotor is with the spinning blades of a wind turbine, which generate electricity. Any electric generator uses mechanical energy to turn the rotor, which in turn creates electrical energy. Even the portable generators that can be bought at a store use a combustion engine of some sort to move a piston that turns the rotor.
    Harnessing the Energy Produced by a Generator

        As the generator creates a current, there must be a way to harness this current and transport it to a power station for distribution across a grid. The way this occurs is through the transfer of the electromagnetic energy created by the spinning rotor to an electrical load. This electrical load is the terminal that takes in the current generated by the generator and transfers it to a circuit. Generally, brushes are used to absorb the electricity from the rotor and connect it with an electrical load, which then sends the energy right on through to the power station and to your home. The brushes strip off the electrons generated from the electromagnetic induction as a result of the spinning rotor.