Power Generation Basics
Alternating Current (AC) - flow of electrical charge reverses direction periodically, in North American households this reverses polarity 60 times in a second, therefore we say it has a frequency of 60 Hertz or 60 cycle.
Above: Single phase AC, the white is voltage and the blue is current
Alternating current shown above is single phase, which means that it has only one source, but you can add together alternating current from other sources, sending it all on the same wire as long as the different electrical sources are well controlled. This helps with producing an almost solid flow of electricity similar to direct current. When many different sources of alternating current are used, this is called multiphase generation. In the graphic below you will see how three phase power looks:
3. Sending Electric Power:
The problem is that electric power looses voltage over distance. Early Pioneers Thomas Edison and Oskar Von Miller solved this by simply using higher voltages which could make the trip, but this soon proved impractical. Alternating current had much more potential to travel over distance because the voltage could be changed - high voltage for a long distance segment, and lower voltage for smaller local powerlines. DC power has reemerged as the best way to send power over distance in the form of HVDC (High Voltage Direct Current) however AC power remains the most common method.
Left: Typical high voltage you see around your city carries 100 kV to 750 kV.
Power Transmission:
Each material has a different conductivity (ability to transmit electric power). Silver, Aluminum, Copper and Gold are some of the best conductors out there. Carbon nanotubes are also conductive and are a cutting edge technology. The thickness and type of wire you use varies depending on which application you are using it for.
Power Conditioning:
With AC power you can transmit over distance, but you must have a way to control the properties of electricity. Using certain devices you can control voltage, amplitude, frequency and the shape of the wave form. Power conditioning is all about manipulating the energy to make it ready to send over distance, then make it ready to perform work using the end device. Click on the item in the graphic below to learn more about it.
Of course the whole point of electric power is to make it do work for humanity, learn about the major devices below which make our world a better place!
Electric Motor:
Electric Motors convert electric power into motion.
Computer:
Computers are made of many interesting parts designed by electrical engineers.
Light and Lasers:
Electricity is converted into visible light and is used for everything from ambient light to industrial processing of materials and communications.
Manipulating electricity to make it work for you is the essence of electrical and most forms of mechanical engineering, be an engineer and build cool things!
