Generators are machines that help convert mechanical energy to electrical energy by using a motor. Nearly all generators are used to store electric power and generate alternating current, which reverses polarity at a fixed frequency. Since a lot of generators are attached to a power network, they must work at the same frequency. Therefore they are known as synchronous generators. http://0-www.school.eb.co.uk.library.hct.ac.ae/eb/article-9106042. Here are some types of generators.
Engine Generators:
Engine-generator is the combination of electrical generator and an engine to form a single piece of equipment. It includes fuel supply, constant speed regulator, cooling and exhausts systems. There are a lot of types of engine generators; they include small, hand-portable generators that can supply over one hundred watts of power. Regardless of the size, generators may run on gasoline, diesel, natural gas, propane, bio diesel or hydrogen.( http://en.wikipedia.org/wiki/Engine-generator) Engine generators are used sometimes when the utility power is not available.
Emergency generators:
They are used as an emergency power supply. They can be used in houses, shops or also when people go camping they use them for some of their stuff during power outages. Emergency generators come in two types, standby and portable generators. Standby generators are connected to your electricity permanently; they also have permanent fuel tanks and produce a large amount of kilowatts, while portable generators are used in isolated areas and come in smaller sizes therefore they produce fewer kilowatts. http://www.ehow.com/about_4588606_emergency-generators.html
AC & DC generators:
A single-phase generator is usually limited to 25 kilowatts or less and generates AC power. DC generators are classified as shunt, series or compound-wound. Most of the DC are compound-wound type; shunt generators are used as battery chargers and as exciters for AC generators. Series generators are usually used for street lights. http://www.engineersedge.com/motors/generators_types.htm
Signal generators:
These are five major types which generate sine waves useful in measuring the response of loudspeakers, amplifiers, microphones, transducers and acoustic sine. They are used for testing radio receivers and they measure signal to noise ratio. http://0-www.school.eb.co.uk.library.hct.ac.ae/eb/article-9067716
Automobile Generators:
Automobiles like cars, buses and trucks need direct-voltage supply to start. In today’s vehicles electric power is created by an alternator mechanically attached to the engine. The alternator normally has a rotor field coil with current through slip rings. The rectifier is used to change the power from alternating to direct form. http://0-www.school.eb.co.uk.library.hct.ac.ae/eb/article-45817
Permanent-magnet generators:
They are simple in that they don’t need any system for their delivery of field current. They are extremely dependable. However, they don’t cover for controlling the output voltage; one of the examples is the wind turbine where the generator output of changeable voltage and frequency is submitted to a power system through an electronic frequency convertor. http://0-www.school.eb.co.uk.library.hct.ac.ae/eb/article-45818
Motors and generators are a bit similar; they both force electrons in the windings to flow through the electric circuit. Before electricity was discovered people were using electrostatic generators, which generated very high voltages and low currents. In the years 1831-1832 Micheal Faraday discovered the operating principle of electromagnetic generators, and later it was called Faraday’s law; he also was able to build the first electromagnetic generator. (http://en.wikipedia.org/wiki/Electrical_generator).
Bibliography:
1-http://0-www.school.eb.co.uk.library.hct.ac.ae/eb/article-9106042
2-http://en.wikipedia.org/wiki/Engine-generator
3-http://www.ehow.com/about_4588606_emergency-generators.html
4-http://www.engineersedge.com/motors/generators_types.htm
5-http://0-www.school.eb.co.uk.library.hct.ac.ae/eb/article-9067716
6-http://0-www.school.eb.co.uk.library.hct.ac.ae/eb/article-45817
7-http://0-www.school.eb.co.uk.library.hct.ac.ae/eb/article-45818
