Showing posts with label Module(1). Show all posts
Showing posts with label Module(1). Show all posts
Monday, June 27, 2011
5:10 AM | Posted by
Anonymous |
Electric power systems are real-time energy delivery systems. Real time means that power is generated, transported, and supplied the moment you turn on the light switch. Electric power systems are not storage systems like water systems and gas systems. Instead, generators produce the energy as the demand calls for it.
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Sunday, June 26, 2011
The Three Types of Electrical Loads
Devices that are connected to the power system are referred to as electrical loads.
Toasters, refrigerators, bug zappers, and so on are considered electrical loads. There are three types of electrical loads. They vary according to
their leading or lagging time relationship between voltage and current.
The three load types are resistive, inductive, and capacitive. Each type has specific characteristics that make them unique.
Understanding the differences between these load types will help explain how power systems can operate efficiently. Power system engineers, system operators, maintenance, personnel, and others try to maximize system efficiency on a continuous basis by having a good understanding of the three types of loads. They understand
how having them work together can minimize system losses, provide
additional equipment capacity, and maximize system reliability.
The three different types of load are summarized below.
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Saturday, June 25, 2011
DC Voltage and Current
Direct current (DC) is the flow of electrons in a circuit that is always in the same direction. Direct current (one-direction current) occurs when the voltage is kept constant, as shown in above Figure. A battery, for example, produces DC current when connected to a circuit. The electrons leave the negative terminal of the battery and move through the circuit toward the positive terminal of the battery.
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Friday, June 24, 2011
Electric Power and Electric Energy are very important Expression you need to know.
Power
The basic unit (measurement) of power is the watt (W), named after James Watt (1736–1819), who also invented the steam engine. Voltage by itself(only)does not do any actual work. Current by itself does not do any real work.
However, voltage and current together can produce real work. The product of voltage times current is power.
P = V * I .........equation (1)
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Thursday, June 23, 2011
Before we start we have to know some basic Concepts and common Expression.in this lesson we will speak about voltage and current.
Voltage
Voltage is the potential energy source in an electrical circuit that makes things happen. It is sometimes called Electromotive Force or EMF. The basic unit (measurement) of
electromotive force (EMF) is the volt. The volt was named in honor of Allessandro Volta (1745–1827), the Italian
physicist who also invented the battery. Electrical voltage is identified by the symbol “e” or “E.” (Some references use symbols “v” or “V”.
Voltage is the potential energy source in an electrical circuit that makes things happen. It is sometimes called Electromotive Force or EMF. The basic unit (measurement) of
electromotive force (EMF) is the volt. The volt was named in honor of Allessandro Volta (1745–1827), the Italian
physicist who also invented the battery. Electrical voltage is identified by the symbol “e” or “E.” (Some references use symbols “v” or “V”.
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Benjamin Franklin is famous for his discovery of electricity.
He started studying electricity in the early 1750s. His observations, including his kite experimentation, verified the nature of electricity. He knew that lightning was very powerful and hazardous. The famous 1752 kite experiment featured a pointed metal bit on the top of the kite and a metal key at the base end of the kite row. The row went through the key and attached to a Leyden Jar. (A Leyden jar consists of two metal conductors separated by an insulator.)
He held the row with a short section of dry silk as insulation from the lightning energy. He flew the kite in a thunderstorm. He initially noticed that various loose strands of the hemp row stood erect, avoiding one another. (Hemp is a perennial American plant used in rope making by the indians.) He proceeded to feel the key with his knuckle and received a little electrical shock.
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