Monday 16 September 2013

Spinning

    In most forms of electric generation, mechanical rotating energy is turned into electricity in coal, nuclear and geothermal power plants, where water is heated into hot steam, which is then used to turn a turbine---a device like a giant fan. In hydroelectric generation, flowing water turns the turbine, and in wind power, the wind turns it. The turbine is hooked up to a generator, which actually produces the power.

The Generator

    The generator has a rotating magnet surrounded by coils of wire. As the magnet turns around, the direction of its magnetic field flips from negative to positive and back again. This field permeates the wire. When wire is permeated in this way by a moving magnetic field, it creates a moving current in the wire. This current is called AC, or alternating current electricity, because it changes from positive to negative to positive continuously instead of flowing in one direction.

Step It Up

    The power is then put through a device called a step-up transformer. When a wire coil with a changing current running through it is put next to a coil without current running through it, the current from the first wire produces a current in the second. If the second coil has more turns of wire than the first, it receives a higher voltage current than the first wire. A set of coils working this way constitute a step-up transformer.

Cables and Substations

    Voltage needs to be stepped up because it might have miles to travel before it gets to your house. Voltage is like pressure---it controls how hard the electricity pushes. Electric wire is a pretty good conductor, but it resists the flow of electricity somewhat. Having high voltage keeps the electricity flowing efficiently without slowing down or losing power. If the electricity has very far to go, it might pass through a substation, where it is boosted again on the way to its destination.

Step It Down

    When the electricity gets to your house, it is run through a step-down transformer. In the United States, this reduces it to 120 volts, but in most other countries, the electricity comes in at 210 to 240 volts. Either way, the electricity is at a much safer level then in the electric main. Even if you were to accidentally get an electric shock from it, it probably wouldn't seriously injure or kill you.The electricity runs through a power meter that records how much you use, and then into the fuse box or circuit breaker in your house. From there, it flows into all the power outlets and built-in appliances.

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