Alternating currently working has a reversing, alternating or oscillating polarity.
It can be stepped up and transmitted over a very long distance.
Most of industries instruments relies on AC. It is usually transmitted over long distance via aluminium cables through thousands of metres from it source.
Most of the world's heavy machinery is powered by AC
Sources and generation of AC.
Alternating current don't occur anaturally, it can be generated from an AC magnet motor and a DC-AC converter also known as inverter.
Magnetic AC motors.
Pure AC can only be generated from motors. Most of the world's alternating electricity is generated from the conversion of mechanical power to electricity.
When coils of insulated copper wire wound a soft iron amarture is made to spin in a magnetic field, electricity is induced into it as the magnetic field knocks out electrons from the copper winding at great speed. The induced current in the coil flows to an external circuit by means of slip ring. The amount of voltage produced depends on the number of turns, the speed and the magnetic field strength.
In real life, magnetic AC motors produces electricity when their shaft is rotatated at high speed. The force use to rotate an AC motor is either by hydro power or internal combustion engines common examples are listed below;
1. Hydroelectric turbine.
Power is generated from water made to turn a dynamo by means of turbine. Dam is built with concrete and stones across a big stream of river, it stops the flow of water and stores it to make a big pool of water.
A little hole is made at the wall and water is made to fall on the turbine which then converts water motion into rotary motion of the turbine.
The rotary motion of the turbine is use to drive the AC Motor by means of belts and gears. The power generated from the motor is then stepped up to thousands of voltage and then transmitted over a very long distance, and then it's stepped down into the required voltage in the consumer grid. A disadvantage of hydro electric power is that, it is cost to maintain and it's usually affected by seasonal changes
2. Wind turbines.
It is a very efficient and clean way of generating electricity from air.
Wind turbines are constructed in form of fan blades, when air flows across it, it moves in a rotary motion which is then used to drive magnetic motors and generate clean and green AC power. The only draw back of wind turbines is that it only works in with much flow of winds.
3.Steam turbines.
This type of power source uses heat energy to heat up water to form steam. The steam produced is passed through a turbine or pistons which rotates a shaft connected to an AC do with belts or gear systems.
Usually coal and gas which are now little used are used for heating yo large volume of water, they have been replaced with nuclear energy from radioactive materials. Nuclear power lasts longer, just a little fuel is enough to power up the steam engine for more than a year.
4. Gasoline generator.
Electricity, is generated from the rotary motion of pistons connected to dynamos with belts or gears. The generator's piston works by igniting a mixture of petrol and air under high pressure which then release hot gas and pushes upward and downward a rod connector connected to a circular disk which is later converted to rotary motion.
5.Power inverters.
DC power from batteries or solar cells is converted to AC with a DC-AC oscillator circuit. Transistors in oscillators are used to switch on and off DC at a very high speed to produce AC. The AC produced is usually a square wave form, advanced inverters can produce pure sine wave AC. The DC power source are usually from batteries charged by solar cells or AC- DC converter circuit fed with AC.
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Electronics