Electrical Engineering Tour

How Nuclear Power Plant Works ?

2012-12-12T20:15:00.000-08:00

Nuclear Energy Power Plant
The Potential Of Nuclear Energy

how a nuclear power plant works?
Why nuclear?, what is nuclear energy, nuclear and the environment, top 10 facts, learn more, nuclear glossary, the pressurized water reactor(PWR): containment structure, pressurizer, steam generator, control rods, reactor vessel, turbine, condenser, generator., boiling water reactor(BWR).
http://www.cleansafeenergy.org/CASEnergyClassroom/HowaNuclearPowerPlantWorks/tabid/170/Default.aspx

types of nuclear reactors
Boiling water reactor, boiling water reactor, pressurized water reactor, liquid metal fast breeder reactor, control rod structure, reactor core, feedwater pump, steam turbine, condenser. primary loop, secondary loop, primary liquid sodium cooling loop, intermediate liquid sodium cooling loop, water and steam loop to turbine.
http://hyperphysics.phy-astr.gsu.edu/hbase/nucene/reactor.html

nuclear physics fission and fusion
Introduction to nuclear energy, with lecture and discussion : nuclear energy : chemistry analogy, binding energy. fission energy : reactions, resources, status. fusion energy : reactions, resources, wastes.
http://acdisweb.acdis.uiuc.edu:16080/NPRE201/coursematerial/nuclear_physics/lecture20.html

nuclear power reactors
Several components common to most types of reactors : fuel, moderator, control rods, coolant, pressure vessel of pressure tubes, steam generator, containment. several different types of reactors : pressurised water reactor, boiling water reactor, pressurised heavy water reactor, gas cooled reactor, light water graphite reactor, fast neutron reactor. floating nuclear power plants, primitive reactors, primary coolants, water, helium, carbon dioxide, sodium, lead, molten fluoride salt, heat transfer for different primary coolants, use of water for cooling.
http://www.uic.com.au/nip64.htm

the story of nuclear energy fission and fusion
Formula by famous scientist Albert Einstein, the equation says, Einstein's voice explaining. nuclear fission, nuclear fusion : deutrium, tritium, neutron, helium, energy.
http://www.energyquest.ca.gov/story/chapter13.html

video power plant tour
Take a virtual power plant tour, what you will need for the tour, tour tips, start the tour : view the entire tour from start to finish, start in the fuel section, start in the water section, start in the electricity section.
http://www.srpnet.com/education/tour/

inside a nuclear reactor
Controlling, coolant, fuel, moderator, shield, steam, electricity, test your knowledge.
http://schools.matter.org.uk/Content/NuclearReactor/NuclearReactorApplet.html

energy information administration
Nuclear power plants operating in the united states as of december 31, 2005, EIA data on reactors, EIA data on nuclear generation, nuclear and uranium forecasts, nuclear regulatory commission.
http://www.eia.doe.gov/cneaf/nuclear/page/at_a_glance/reactors/states.html

the virtual nuclear tourist, nuclear power plants around the world
Current hot topics, terrorism concerns, location, private spent fuel storage, russian enriched fuel, effects of low levels of radiation, transportation of nuclear waste, decommissioning of nuclear plants, reprocessingm advanced reactors, inside the nuclear power plants, US locations plant maps, plant status events assesment operational experience NRC plant assesments reactor oversight, sample preliminary safety analysis report, world locations plants, web searches for specific us power plants.
http://www.nucleartourist.com/

Pressurized Water Reactors
http://www.nrc.gov/reactors/pwrs.html

nuclear power plant operations
Reactor system, Pressurized Water Reactor System, Protective Barriers.
http://www.hsem.state.mn.us/HSem_view_Article.asp?docid=251&catid=3

The History and Inventor of Nuclear Power plant

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In 100 BC an Alexandrian Greek speaking philosopher by the name of Ctesibius
invented the piston - pump.
In 1606, Italian scientist Giovanni Batista della Porta of Naples heated water in a flask until the water turned into steam.

In the 1600's several scientists continued work on steam powered pumps. Robert Boyle proposed the steam engine in 1678.

In 1680's a gunpowder explosion was used to heat water. Jean de Hautefeuille tried to up water, and Dutch astronomer Christiaan Huygens tried a piston in a

cylinder.

In 1712, Thomas Newcom and John Calley built their first successful steam engine.

In 1769 Nicholas Cugnot built the first mechanically propelled road vehicle

In 1789 Uranium was discovered by Martin Klaproth, a German chemist, and named after the planet Uranus.

In 1895 Ionising radiation was discovered by Wilhelm Rontgen by passing an electric current through an evacuated glass tube and producing continuous X-rays.
In 1896 Henri Becquerel found that pitchblende an ore containing radium and uranium caused a photographic plate to darken. He went on to demonstrate that

this was due to beta radiation electrons and alpha particles helium nuclei being emitted.
In 1896 Pierre and Marie Curie gave the name 'radioactivity' to this phenomenon.
In 1898 isolated polonium and radium from the pitchblende. Radium was later used in medical treatment.
In 1898 Samuel Prescott showed that radiation destroyed bacteria in food.
In 1902 Ernest Rutherford showed that radioactivity as a spontaneous event emitting an alpha or beta particle from the nucleus created a different element.

He went on to develop a fuller understanding of atoms.

In 1905 This was the first experimental confirmation of Albert Einstein's paper putting forward the equivalence between mass and energy, which had been

published.

In 1919 he fired alpha particles from a radium source into nitrogen and found that nuclear rearrangement was occurring, with formation of oxygen.
Niels Bohr was another scientist who advanced our understanding of the atom and the way electrons were arranged around its nucleus through to the 1940s.

In 1911 Frederick Soddy discovered that naturally-radioactive elements had a number of different isotopes radionuclides, with the same chemistry.
In 1911, George de Hevesy showed that such radionuclides were invaluable as tracers, because minute amounts could readily be detected with simple instruments.

In 1932 James Chadwick discovered the neutron.
In 1932 Cockcroft and Walton produced nuclear transformations by bombarding atoms with accelerated protons.

In 1934 Irene Curie and Frederic Joliot found that some such transformations created artificial radionuclides.
The next year Enrico Fermi found that a much greater variety of artificial radionuclides could be formed when neutrons were used instead of protons.

In January 1939 Frisch then confirmed this figure experimentally
1939 developments sparked activity in many laboratories. Hahn and Strassman showed that fission not only released a lot of energy but that it also released additional neutrons which could cause fission in other uranium nuclei and possibly a self-sustaining chain reaction leading to an enormous release of energy.

In 1900 Work on radioactive minerals found in central Asia began
Enrico Fermi (1901-1954), an Italian American physicist who won the 1938 Nobel Prize in Physics .
Otto Hahn (1879-1968), a German physical chemist who won the 1944 Nobel Prize in Chemistry.
Enrico Fermi (1901-1954), an Italian American physicist who won the 1938 Nobel Prize in Physics Otto Hahn (1879-1968), a German physical chemist who won the

1944 Nobel Prize in Chemistry Lise Meitner (1878-1968), an Austrian Swedish physicist Hyman G. Rickover (1898-1986), a Polish American naval officer

Discovering Fission Nuclear fission involves the splitting of an atomic nucleus, leading to the release of large amounts of energy. Nuclear fission was discovered in Germany in 1938 by Otto Hahn after he had bombarded uranium with neutrons and observed traces of radioactive barium. Meitner and her nephew, Otto Robert Frisch, were able to calculate the enormous energy that would be released in this type of reaction. They published their

results early in 1939. Nuclear fission was quickly verified in several laboratories.
Danish physicist Niels Bohr soon demonstrated that the rare uranium 235 (U-235) isotope is much more likely to fission than the common uranium 238 (U-238) isotope, which makes up 99.3 percent of natural uranium.

In 1909 St Petersburg Academy of Sciences began a large-scale investigation
1917 Revolution gave a boost to scientific research and over 10 physics institutes were established in major Russian towns, particularly St Petersburg, in the years which followed.

In the 1920s and early 1930s many prominent Russian physicists worked abroad, encouraged by the new regime initially as the best way to raise the level of expertise quickly. These included Kirill Sinelnikov, Pyotr Kapitsa and Vladimir Vernadsky.

In 1931 Kirill Sinelnikov returned from Cambridge to organise a department at the Ukrainian Physico-Technical Institute FTI in Kharkov which had been set up in 1928.

In 1933 became the Department of Nuclear Physics under Kurchatov with four separate laboratories.
In 1940 saw great advances being made in the understanding of nuclear fission including the possibility of a chain reaction. At the urging of Kurchatov and his colleagues, the Academy of Sciences set up a "Committee for the Problem of Uranium" in June 1940 chaired by Vitaly Khlopin

In June 1942 the US Army took over process development, engineering design, procurement of materials and site selection for pilot plants for four methods of making fissionable material.

In August 1943 an agreement was finally signed by Mr Churchill and President Roosevelt in Quebec.
In December 1951 The first nuclear reactor to produce electricity (albeit a trivial amount was the small Experimental Breeder reactor (EBR-1) in Idaho, in

the USA, which started up.

In October, 1956 It began producing about 90 megawatts of electric power.
In December 2, 1957, on the fifteenth anniversary of the first controlled nuclear chain reaction, the Shippingport Atomic Power Station in Shippingport,

Pennsylvania, became the first full-scale commercial nuclear power plant in the United States.

In September, 1959 The Dresden Nuclear Power Station, completed by Commonwealth Edison.
In 1973, forty-two plants were in operation producing 26,000 megawatts, fifty more were under construction, and about one hundred were on order.
In 1986, more than one hundred nuclear power plants were operating in the United States, producing about 60,000 megawatts of power.

In December 1993, the total number of nuclear power plants in the United States is 109, collectively producing 610 billion kWhs of electricity.

10 Largest Nuclear Power Plants In The World

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1. Kashiwazaki-Kariwa Nuclear Power Plant 8,212 Mega Watts

Niigata prefecture, Japan

Towns of Kashiwazaki and Kariwa

Has seven nuclear reactors.

The station is about 220 km northwest of Toyko

The plant, owned by Tepco, was built in 1985

2. Uljin Nuclear Power Plant 6,157 Mega Watts

Gyeongsangbuk-do province, South Korea

Has six nuclear reactors have been built to withstand 6.5 magnitude earthquakes

3. Yonggwang Atomic Energy Plant 6,137 Mega Watts

Yonggwang, South Korea

Has six nuclear reactors that each produce over 900 megawatts of power.

The plant, which began operation in 1978

4. Zaporizhzhia Atomic Energy Plant 6,000 Mega Watts

Enerhodar, Ukraine

The plant has six generators that The world’s worst nuclear disaster. About 400 times more radiation than the atomic bomb dropped over Hiroshima during World War II.

5. Gravelines Nuclear Power Plant 5,706 Mega Watts

Gravelines, France

The six reactors came online between 1980 and 1984 and the plant recently completed quite a milestone

It generated its 1000 billionth kilowatt hour of energy.

Local fish farmers use the water that carries waste heat from the plant to help raise European sea bass and other fish.

The warm water helps the fish grow faster.

6. Paluel Nuclear Power Plant 5,528 Mega Watts

Normandy, France

The second largest of its kind in France with four reactors that generate over 1,300 megawatts of power each hour.

The rest of the country’s nuclear stations are located away from the coast and get their cooling water from rivers.

About 11 of the 15 inland plants have evaporative cooling towers to lessen the need for fresh water.

7. Cattenom Nuclear Power Plant 5,448 Mega Watts

Cattenom, France

The station is owned by Electricite de France (EDF),Europe’s biggest power generator and the world’s second biggest utility company.

In April, about 2,000 people protested outside the site along with thousands across the country over the dangers of nuclear power.

France is one of the largest consumers of nuclear power, with 75 percent of its electricity coming from the source.

8. Bruce Nuclear Power Plant 5,090 Mega Watts

Inverhuron & Tiverton, Canada

The largest nuclear plant in North America.

The station takes up 2,300 acres near Lake Huron in Ontario.

It has eight nuclear reactors, but only six are operational.

The company is on track to restart the other two reactors by 2012, adding another 1,500 megawatts of power to the station. Once all eight are operational, the station will become the world’s second largest nuclear plant by capacity.

9. Oi Nuclear Power plant 4,710 Mega Watts

Fukui prefecture, Japan

Owned by Kansai Electric Power Company (KEPCO)

One of Japan’s largest utilities.

The plant houses four nuclear reactors that each generate over 1,000 megawatts of power per hour.

KEPCO has come under fire in the past for incidents at its nuclear plants.

In 2004, five employees were killed at its Mihama nuclear plant from a burst of steam, which was blamed on neglected safety checks.

In 2006, two employees were also injured in a plant fire.

10. Fukushima Daiichi 4,696 Mega Watts

Okuma, Japan

The world’s 10th largest nuclear station before Japan’s catastrophic earthquake and tsunami.

The plant started operations in 1971 and has six nuclear reactors, which were badly damaged on March 11.

Tepco had planned two more reactors at the site, but the company now plans to abandon these and scrap the site entirely.

Most of the reactors are old boiling water reactors (BWR) based on a GE design.

In February, Tepco admitted to the Japanese nuclear safety agency that it had submitted false inspection and safety reports.

Nuclear Power Plant Advantages and Disadvantages

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What Are Advantage and Disadvantages of Nuclear Power Plant

Advantages of A Nuclear Power Plant
1. Breeder reactors create more usable fuel than they use.
2.A nuclear aircraft carrier can circle the globe continuously for 30 years on its original fuel while a diesel fueled carrier has a range of only about 3000 miles before having to refuel.
3.Current nuclear waste in the US is over 90% Uranium. If reprocessing were made legal again in the US we would have enough nuclear material to last hundreds of years.
4.They can be sited almost anywhere unlike oil which is mostly imported.
5.Almost 0 emissions (very low greenhouse gas emissions.
6.A single nuclear reactor can produce a substantial amount of power. A nuclear reactor produces much more power per unit weight of nuclear fuel than conventional energy sources like coal and oil. The production of nuclear power does not release carbon dioxide into the atmosphere and hence does not contribute to global warming.
7.Nuclear power plants don't take up much space. This allows them to be placed in already developed areas and the power does not have to be transferred over long distances.
8.Nuclear power plants already exist and are available worldwide. So in comparison to, for example, nuclear fusion, the technology does not have to be developed first.
9.Another advantage of nuclear power is that nuclear energy is by far the most concentrated form of energy, so it can be produced in large quantities over short periods of time.
10.Nuclear power generation does emit relatively low amounts of CO2. Nowadays global warming because of the greenhouse gases is a hot topic. The contribution of nuclear power to global warming is relatively little.

Disadvantages of A Nuclear Power Plant
1.Mishaps at nuclear plants can render hundreds of square miles of land uninhabitable and unsuitable for any use for years, decades or longer, and kill off entire river systems
2.Early nuclear research and experimentation has created massive contamination problems that are still uncontained. Recently, for instance, underground contamination emanating from the Hanford Nuclear Reservation in Washington State in the U.S. was discovered and threatens to contaminate the Columbia River
3.Nuclear plants are more expensive to build and maintain.
4.Nuclear reactors are particularly vulnerable to terrorist attacks. The construction cost of a nuclear reactor is high. It takes a significantly long time to construct nuclear plants. At present, the reserves of uranium, a critical nuclear fuel, are limited in the world. Nuclear plant workers may be exposed to high levels of radiation, which can cause cancer and other ailments.
5.Nuclear reactors only last for about forty to fifty years, so where they are extremely productive, they break down and are costly to replace.
6.It is a high risk power supply. Of course a nuclear power plant has a very high security standard, but it is impossible to build a plant with a 100% security. We all know what horrible consequences there will be if an error or accident occurs in this plant.
7.A nuclear meltdown can often occur which will release massive amounts of radiation into the community.
8.nuclear energy can create more problems than they solve. Nuclear mishaps do not happen very often, but when they do, it creates a catastrophe that can damage the country and surrounding area for years to come.
9.The technology used for generating nuclear power can also be used for producing nuclear weapons. The country of North Korea is a classic example of this. The technology still does not exist to use nuclear power in relatively smaller devices like automobiles.
10.These plants also consume large amounts of water, which can damage marine life and affect the wildlife population in the area.

Free PDF Download Advantages and Disadvantages
Energy & the Environment
Advantages Nuclear fuel does not make harmful greenhouse gases. You only need a very small amount of nuclear fuel to make a lot of energy Disdvantages The waste that is produced when using nuclear fuel is radioactive and very harmful. It needs to be disposed of carefully Nuclear power stations are at risk from terrorist attack and sabotage. World uranium supplies may run out in about 50 years.

Free Download The Danger of Nuclear Power Plant

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The Risk and Danger of Nuclear power plant should everyone know why? because its affects in the human race, our health, our family etc. by way of teaching or learning I have here list of a free download pdf file from different site.
A dangerous waste of time greenpeace
The nuclear power industry is attempting to exploit the climate crisis by aggressively promoting nuclear technology as a “low-carbon” means of generating electricity. Nuclear power claims to be safe,
cost-effective and able meet the world’s energy needs. But nothingcould be further from the truth.

Understanding radiation
Radioactive materials are composed of atoms that are unstable. An unstable atom gives off its excess energy until it becomes stable. The energy emitted is radiation. Radiation has a cumulative effect. The longer a person is exposed to radiation, the greater the risk.

Nuclear Facts
Despite the fact that a national global warming emissions cap-and-trade system would materially assist the economic case for nuclear power, the nuclear industry has not been willing to openly advocate for such a system.

Nuclear Power Plant Security
Physical security at nuclear power plants involves the threat of radiological sabotage adeliberate act against a plant that could directly or indirectly endanger public health and safety through exposure to radiation.

Natural Disasters and Safety Risks
A typical nuclear power station will be connected to the electric grid through three or more transmission lines. Should these power lines go down or a regional electrical grid collapse occur, onsite emergency generators diesel, gas turbines or in few cases hydroelectric dams are designed to automatically start with manual
backup capability.

Radiation Risks and Realities
These findings allow us to use radioactive materials for beneficial purposes, such as generating electricity and diagnosing and treating medical problems. For these many benefits, excessive radiation exposure can also threaten our health and the quality of our environment.

The Tolerability of Risk
But in fact many people are bothered about nuclear power and other industrial risks and have become more so during the years since Sir Frank Layfield wrote his report.

How Does Electric Tractions Works? Question and Answer

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Electric Traction Theory
Steam Locomotive, Diesel Engines, Electric traction, Advantages, Electrical transmission, which is usually applied to high power units, has following advantages, The Direct and Alternating Current.

what is electric traction?
electric Traction means to use electic motors for railway service, Act of drawing or being drawn is known as traction.If electric supply is used for driving a locomotive, the system is known as electric traction.Electric traction may be A.C. or D.C. powered.e.g.600V dc is given to tramways and trolley buses.

ELECTRIC TRACTION
The electric locomotive and electric motor coach may be regarded as natural developments that have followed steam traction. New conditions have set new standards in railway travel. This is exemplified in the rapid development of electric suburban train services for the new built-up areas spreading in all directions round large cities.

Electric Traction Drives
This page describes the way electric motors on locomotives and multiple units drive the axles and wheels. See also the Electronic Power, Multiple Unit Operation, DC Traction Motor Systems and Electric Traction Glossary pages.

Answer tips/answer samples of What is electric traction?
Electric traction systems use DC motors, but nowadays, some people tend to use magnetic traction instead of electric ones.

ELECTRIC TRACTION FOR AUTOMOBILES - Free PDF download
a comparison concerning electric traction drives for passenger cars is given. Electric traction drives presently available on the market are analyzed and future developments are described.

Power Supply Installation in Electric Traction - Free PDF download
The book on "Power Supply Installation in Electrical Traction" was brought out by Institution of Railway Electrical Engineers (IREE) long back. Since, lot of changes have taken place in the field of Power Supply Installation, it has become necessary to incorporate the changes in this volume. Few additions and modifications in the field of Power Supply Installations are included in this book.

Question and Answer of Electric Traction

1. Overall efficiency of steam locomotive system is close to answer 5 to 10 percent
2. Maximum horse power of steam locomotive is answer 1500
3. The efficiency of diesel locomotives is nearly answer20 to 25 percent
4. The range of horsepower for diesel locomotives is 1500 to 2500
5. What motor is used in tramways? answer DC series motor
6. The advantages of electric braking is It prevents wear of track
7. What is the braking system on the locomotives answer Regenerative breaking on electric locomotives
8. What is the coefficient of adhesion highest? when answer the rails are dry
9. The estimated speed of the train, including the time of stop at a station, in addition to the actual running time between stops, is called its answer Schedule speed
10. Which of the following types of services consume the least specific energy? Main line service
11. Locomotives have two bogies with two driving axles with individual drive motors.
12. A composite system is made up of answer single phase power received is converted into DC or three phase power AC system
13. For 600 volts DC line for tram cars what is the correct voltages Track are connected to negative of the supply
14. Free running and coasting periods are generally long in case of which of the following services? answer Main line service
15. A train runs at an average speed of 50 kmph between stations situated 2.5 km apart. The train accelerates at 2 kmph and retards at 3 kmph. Speed time curve may be assumed to be trapezoidal. The maximum speed with these parameters will be answer 57.75kmph
16. Suri transmission is answer Hydro mechanical
17. When a locomotive for Indian Railways is designed as WAMI, what does the letter W indicate? answer The locomotive is to run on broad gauge track
18. The main differece between speed time curve of main line service as compared to suburban services lies in answer longer free running periods, longer coasting periods and shorter acceleration and braking periods

Transformer Built In Protection and Cooling Tutorials

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Protection Devices Built In For Safe Operation of A Transformer

Conservator

It is a sort of a drum, mounted on the top of transformer. A level indicatoris fixed to it. Conservator is connected through a pipe to the transformer containing oil. This oil expanse and contracts depending upon the heat produced so the oil level in the conservator rises and falls. Pipe connected to the conservator is left open to the atmosphere through a breather so that extra air any go out or come in.

Breather

Is is a box containing calcium chloride to absorb moisture of air entering the conservator as it sis well known fact that the insulating property of the transformer oil is lost even if a small amount of moisture enters in it, so the dry air is allowed to pass in through this breather.

Temperature Gauge

It is fitted to a transformer which indicates the temperature of transformer oil.Explosion Vent

It protects the transformer tank from the gases induced by any type of short circuit in the transformer.

Pipes

These are fitted for cooling the transformer oil. The hot oil circulates through these pipes where it becomes cool due to the air touching.

Important Facts About Transmission and Distribution Transformer

1. Eddy current losses in a transformer are minimised by laminating the core, the lamination being insulated from each other by a light coat of core plate varnish.

2. The basic property of the transformer is that it changes the voltage level of an alternating current signal without changing power, frequency or shape.

3. The primary and secondary voltages are 180 degree out of phase in transformer.

4. Eddy current lossesin transformer core are reduced by decreasing the thickness of laminations.

5. The resistance of low voltage side of a transformer is less than the resistance of its high voltage side.

6. The efficiency of a transformer is normally in the range of ninety ot ninety eight percent.

7. The reactance of transformer is determined by its leakage flux.

8. The principle of working of a transformer is mutual induction.

9. Transformer is used to change the valuesof voltage.

10. The path of the magnetic flux in a transformer has low reactance.

11. Electric power is transformed from one coil to the other coil in a transformer magnetically.

12. Ideal transformer assumptions do not include zero reactance of windings.

13. Preferably, the resistance between the primary and the secondary of a transformer should be as low as possible.

14. The main function of the iron core in a transformer is to decrease the reluctance of the magnetic path.

15. Magnetic circuit is common in the two windings of a transformer.

16. A transformer operates at power factor depending on the power factor of the load.

17. The lamination are made from nickel alloy steel stampings.

18. The steel for construction of transformer core is made so as to have high permeability and low hysteresis.

19. The special silicon stell in used for laminations because hysteresis losses are reduced.

20. Power transformer are designed to have maximum efficiency at near full load.

Cooling Of Transformer

Natural Cooling

The cooling is provided through natural circulation of air. The surface area of the core and the transformer winding are sufficient to dissipate the heat generated. It is used for small transformer from ten kva to fifteen kva.

Natural Oil Cooling

The transformer is placed in tank filled with oil known as transformer oil. The oil used in the tank not only helps cooling the transformer but also provides insulating for the winding. The oil takes the heat produced by the transformer, the oil circulate through the pipes and tank. The hot oil becomes lighter in weight and goes up from where comes down through pipes to the bottom of the tank after cooling. The oil level should never fall below the upper ends of pipes.

Oil Blast Cooling

In this method radiator tanks are provided to the side walls of the main tank. The oil circulators through these radiators from the main tank. The radiator tanks are cooled by air blast. The system of cooling is known as oil blast type. It is used for transformer rated above five hundred kva.

Force Water Cooling

The winding of transformer is placed inside the tank containing oil and cold water is passed through the copper pipe spiral kept in the transformer oil. The cold water absorbs and carrier away the heat of the oil. The pressure of the water is not kept greater than the pressure of the oil in the tank because in case of leakage in the pipe, the water will enter into the oil. It is used for transformer having output greater than five hundred KVA.

Force Air Cooling

In this method the air is first filtered to eliminate moisture and dust particless and this filetered air under pressure is forced to passed through the winding care of the transformer and the dusts provided in them. This method is used where there

is a scarcity of water.

Power Transformer Tutorials Links

Tutorials on Electrical Power Factor Correction

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All About Power Factor Links

Power Factor Meter
A direct reading instrument for measuring power factor. It is provided with a scale graduated in power factor.

Power Factor Relay
Power system device function numbers. A relay that operates when the power factor in an alternating current circuit rises above or falls below a predetermined value.

Power Feeder
A feeder supplying principally a power or heating load.

Power Frequency
The value of frequency used in the Electrical power system, such as 50 hz or 60 Hz.

Power Inverter
A converter unit in which the direction of average power flow in from the DC circuit to the alternating circuit.

Power Monitor
A functional module that monitors the status of the primary power source to the system, and signals when that power has strayed outside the limits required for reliable system operation. Since most systems are powered by an alternating current source, the power monitor is typically designed to detect dropout or
brown out conditions on alternating current lines.

Power Factor Question and Answer

1. If a current of 10 amperes at a power factor of 0.8 lagging is taken from 250 Volt alternating current supply, the reactive power of the system will work out to be 1500 VAR.
2. Many industrial tariffs penalise consumers whose power factor falls below 0.8.
3. Power factor improvement may be achieved the use of synchronous motor.
4. One of the reasons for improving the power factor is to decrease the reactive power.
5. The power factor of incadescent bulb is unit.
6. The power facotor of an inductive circuit can be improved by connecting a capacitor to it in series.
7. The capacitor of power factor correction are rated in terms of KVAR.
8. In an alternating current circuit, a low value of with reactive volt ampere compared with watts indicates high power factor.
9. It is not easy to find the value of impedance for a parallel circuit but power factor can easily be obtained as a ratio of active current to line current.
10. In a series circuit consisting of resistance and reactance, power factor is a defined as the ratio of resistance to impedance.
11. In pure reactive circuit, the power factor is zero.
12. Power factor is defined as the ratio of watts to volt ampere.
13. For a parallel circuit consisting of resistance and reactance the value of power factor is the ratio of impedance to resistance.
14. The power factor of an alternating current circuit containing both a resistor and a conductor is between 0 - 1 leading.
15. In a given circuit when power factor is unity the reactive power is zero.
16. A poor power factor results in overloading of transformer as well as alternators.
17. For the same load, if the power factor of load is reduced, it will draw more current.
18. The power factor of the magnetizing component of a transformer is always leading.
19. Another reason for improving the power factor is to avoid poor voltage regulation.
20. The advantage of using static capacitors to improve the power factor is that they are almost loss free.

Causes of Low Power Factor
1. Arc lamps and industrial heating furnaces are typical of low power factor operating equipments.
2. During the night time when load is less the supply voltage increase which in turn, causes the magnetising current of transformers and motors to increase. Therefore, the power factor at which the system operates becomes low.
3. Mostly alternating current motors are of induction type. These operate on low lagging power factor.

The Adverse of Low Power Factor
1. With low p.f. cost of generation and transmission increases due to increase in current and use of thicker wires and bigger switches.
2. Low pf. makes the voltage regulation of generators, transformer and transmission line greater.
3. For a given p.f. to be supplied, the current is increased due to low p.f. in causes increase in copper losses, and decreases the efficiency of both apparatus and supply system.
4. With low pf generators, transformer, swithes transmission lines become over loaded.

Electrical Transformer tutorials Current Potential and Auto tutorials

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Current Transformers The primary of this transformer consists of a few turns or even a single turn to carry the current to be measured and is connected in series with the main circuit. The secondary winding with large number of turns supplies a reduced current to the ammeter. The meter scale is calibrated directly in terms of the primary circuit current.The core is worked at low flux density so that, at all loads, secondary current is a constant ratio of the main circuit current. When the cuurent is flowing in the primary circuit, the secondary circuit should not be opened. In that case high voltage may be induced in the secondary and the core may become over saturated, heated up and thereby damage the magnetic properties permanently.

Potential Transformer
This is used to reduce the primary voltage to a safe value for operation of voltmeter and other instrument. Primary is connected to the H.T. to be measured and the secondary to a voltmeter. It is so designed that the ratio of primary to secondary is constant throughout. To limit the short circuit in case of failure of the transformer, limiting resistances are placed in series with the H.T. winding.

Auto-transformer works on the priciple of self Induction
It has only one winding which performs the function of both primary and secondary winding. As in ordinary transformer, the transformation ratio in autotransformer, is also equal to the turns ratio.
In case of step down transformer, the complete winding acts as primary winding while the tapped section of this winding works as secondary winding. In the step up transformer, the whole winding works as secondary winding and its there is much saving of copper. These transformers are used as regulating transformers where only a small variation of voltage is required. It is mainly used for starting and speed control of induction motors. It suffers from a disadvantage that the two windings are not electrically separate and in case of failure of insulation between the two, either a sever shock may be felt on the low voltage side.

Various parts of a Transformer
Primary winding
Secondary winding
Oil level
Conservator
Breather
Drain cock
Tube for cooling
Transformer Oil
Earth Point
Explosion vent
Buchhol's Relay
H.T. Terminals
L.T Terminals

Free Pdf file about the kinds of Transformer

Current Transformers
Current transformers are used in electrical grids for measurement and protective applications to provide signals to equipment such as meters and protective relays by stepping down the current of that system to measurable values.

Instrument Transformers
Technical Information and Application Guide

Selecting Current Transformers
As engineers, we are aware that electrical power systems have grown. How much have they grown?

Current Transformer Principles and Operation
Used with watt transducers enable the owner to control demand as well as monitor building and/or tenant power consumption. When CT's are used with Current Transducers, the result is an excellent method of diagnosing the performance of fans,pumps, chillers.

Potential Transformer
Voltage transformers connected line-to-ground cannot be considered to be grounding transformers and must not be operated with the secondaries in closed delta because excessive currents may flow in the delta.
VOLTAGE TRANSFORMERS
Potential transformer are so small that they may be neglected for protective-relaying purposes if the burden is within the "thermal" volt-ampere rating of the transformer. This thermal volt-ampere rating corresponds to the full-load rating of a power transformer.

Auto Transformer
The currents drawn by these two windings are out of phase by 180◦. This prompted the use of a part of the primary as secondary. This is equivalent to fusing the secondary turns into primary turns.

Transformers vs. Autotransformers
A transformer converts audio from one voltage and impedance to a different voltage and impedance. Transformers are passive which means they do not require a power supply to operate.

All About Electrical Distribution and Power Transformer Tutorials

2012-03-08T16:42:00.000-08:00

This is All About Transformer its principles, Definition, Testing Facts and Tutorials

Transformer Classification

Transformer Definition
It is a static device for transforming electrical energy from one alternating current circuit to another without any change in frequency. It changes voltage from high to low and low to high with a corresponding increase or in decrease current. If the voltage is increased it is said to be stepped up. If it is decreased, then it is said as stepped down.

Electrical Transformer Principle
When one coil like primary is connected to the alternating current supply current flows and an alternating flux is set up in the core. Most of this flux links with the second coil secondary. Law of electromagnetic induction.If the circuit is completed, current will flow. The secondary voltage depends upon the ratio of secondary turns to primary turns.

The Testing of the Transformer

Two test are performed on the transformer which are open circuit test and short circuit test. These tests are performed to determine the parameter or constants of transformer, efficiency and regulation.

1. Open Circuit Test
This is also called no load test. It determined the iron losses and the no load current. One winding of the transformer, usually the low voltage side is connected to its normal supply with an ammeter to measure the voltage applied to the winding and a wattmeter to measure taken by transformer at no load. the high voltage winding is kept open. Under these conditions normal flux will be set up in the core, therefore, normal iron losses will occur. The current taken will be wattmeter will indicate the iron losses.

2. Short Circuit Test
This test is used to determine the full load copper losses and the equivalent resitances and reactances referred to the metering side. In this test on the high voltage winding a reduced value of the voltage is increased until full load current is flowing in this winding. The applied voltage is a small fraction of the normal working voltage, the mutual flux produced is very small and hence the core losses at this voltage can be neglected. The wattmeter during this test gives the total coppery losses.

What is Distribution Transformer?
Transformer up to a size of 200 KVA, used to step down the distribution voltage to a standard service voltage, are known as distribution transformers. They are kept in operation all the 24 hours a day whether they are carrying load or not. Energy is lost in iron losses throughout the day while the copper losses account for loss in energy when the transformer is loaded. Therefore, the distribution transformer should have their iron losses small as compared to full load copper losses, in other words, they should be designed to have maximum efficiency at a load much lower than full load about 50 percent. Owing to low iron loss, the distribution transformer have good all day efficiency. These transformer have a good voltage regulation.

What is Power Transformer?
These transformers have rating about 20 KVA and are in generating stations and substations at each of a power transmission line for stepping up or stepping down the voltage. They may be either single or three phase units. They are put in operation during load periods and are disconnected during light load periods. Therefore the power transformer should be designed to have maximum efficiency at or near full load. Power transformer are designed to have considerable greater leakage reactance than that permissible in distribution transformers because in the case of power transformer, voltage regulation is less important than current limiting effect of higher leakage reactance.

Important Facts About Transformer
1. In and ideal transformer on no load, the primary applied voltage is balanced by the secondary.
2. The concentric windings are used in core type transformer with LT winding placed next to core.
3. Cross over windings are used for high voltage winding of small rating transformers.
4. The magnitude of mutual flux in a transformer is same at all levels.
5. The induced emf in the transformer secondary will depend upon frequency, flux and number of turns in the secondary.

Electrical Illumination Tutorials and Its Engineering Definition

2012-02-22T03:18:00.000-08:00

Light

The light is defined as the energy radiated in the form of waves which produces the sensation of vision to the eyes. It may be natural light from sun or the artificial from the means created by human beings.

Lumen

It is the unit of luminous flux and is defined as the luminous flux emitted per unit solid angle by a point source of one candle power.

Brightness

The brightness is defined as the luminous intensity per unit projected area of either a source of light or reflecting surface. It is denoted by B and the unit is stib which is nothing but candle per centimeter squared, other unit is nit which is candle per meter squared.

Coefficient of Utilization

It is defined as the ratio of the lumens actually received by a particular surface to the total lumens emitted by the luminous source. The coefficient of utilization or the utilizing factor is the total lumens actually received by the working plane per total lumens emitted by the light source.

Candle Power

The candle power is the light radiating capacity of a source in a given direction. It is defined as the number of lumens given out by a source in a unit C.P. and one meter away from it.

Colour

The sensation of colour is due to the difference in the wavelengths of the light radiations. Visible light can have length between 4000 A to 7500 A and colour varies in the way.

Luminous Intensity

The luminous intensity in any given direction is the luminous flux emitted by a source per unit solid angle. It is represented by I and measured in candle power.

Luminous Flux

It is the total quantity of light emitted by the source of light per second. It is represented by symbol O or F. It is measured in lumen. The total flux emitted by a source of I candle is 4 pi times I lumen where I is the luminous intensity of the source.

Some Characteristics of a good Illumination

1. The light source should not strike the eyes of the worker.
2. The type and size of the lamp should be correct.
3. Location should be proper.
4. Reflecting equipment should be suitable.

The Advantages of Correct Illumination

1. Factory production increases
2. Accidents decrease
3. Wastage of jobs decreases.

The sources of light is Three practicable ways of producing light are incandescent of heated filament and electric are glow discharge. Where the incandescent filament lamp is the light obtained by passing, current through a high resistance called the filament, this current being sufficient to raise the filament to luminosity. The filament is enclosed in an evacuated glass bulb. The object of the vacuum is first to prevent the filament burning away to reduce loss of heat by convection. The filament must be a conductor and must be capable of withstand a hight temperature.

All About Electrical and Electronics Measurement Facts and Tutorials

2012-02-16T16:50:00.000-08:00

It is important as an electrical engineer, we have a great knowledge how electrical or electronics measuring works, because the income of the electrical company depends on. listed below are key facts and tutorials that electrical engineer you should know.

A mirror is provided behind the pointer in measuring instruments to eliminate the reading errors, due to inclined observations, by removing parallel between the pointer and its image in the mirror.

Threshold of sensitivity with respect to instrument is the smallest signal that results in a detachable output.

Schering Bridge can be used to measure capacitance and its power factor.

Hay bridge is used to measure inductance of a high Q inductor.

Damping provides braking action on a meter pointer.

In moving coil meters, damping is provided by the aluminum frame.

Moving coil instruments are used in DC circuits only.

The sensitivity in accuracy of an instrument does not depend on hysteresis or dead bond, amplitude distortion and frequency response.

The sensitibity inaccuracy of a recording instrument means the maximum error in sensitivity displayed by a pen.

When using any instrument for measurement or testing an electrical circuit, your personal safety should be considered first.

The resolution of an indicating instrument is the smallest change in applied stimulas that indicates a detachable change in deflection.

The accuracy classes of industrial measuring instruments should be 1, 2.5, 2.5 and 5.

In measuring instrument, the internal resistance of ammeters should be very small, and that of voltmeters very high.

Meter accuracy is determined by full scale deflection.

The reliability of an instrument means degree to which as instrument's readability continues to remain within specific limits.

To reduce the effect of a voltmeter upon the circuit under test, we should get an instrument with a higher internal resistance.

To increase the range of a voltmeter a high resistance is connected in series.

The function of the zero adjust control in a multimeter is that the zero point is corrected with the help of this control.

If moving iron type ammeter is connected to a circuit, and we interchange its connected, then its reading will not change.

Eddy current damping methods is common in moving coil instruments.

The main reason for using springs in a measuring instrument is to control the pointer movement.

A moving iron type instrument has a nonlinear scale.

In moving coil instruments, the scale used is linear scale.

The function of a shunt in an ammeter is to by pass the current.

The shunt resistance in an ammeter is to bypass the current.

External shunts are generally used for measuring currents greater than about 30 ampere.

Induction type single phase energy meter is true watt hour meter.

A wattmeter can measure AC as well as DC power.

Meggar essentially is megaohmmeter. Meggar's operation is based upon moving coil meter.

If the aproximate value of the current to be measured is not known, the measurement should start on the highest range and then increase the range.

An electrodymic meter can be used to measure DC as well as AC voltage.

Meggar is an instrument to measure insulation resistance.

The cell used in a potentiometer is a lead accumulator.

A coil of high inductance equipment is not a part of meggar with a coil of high inductance.

The number of the coils in the meter of meggar is two.

With the measurement terminals open circuit, the infinity reading of meggar is due to currents in the coil connected across the measurement points.

Carey Foster Bridge is specially designed to determine the difference between two nearly equal resistances.

Maxwell bridge is used to measure inductance of a low Q inductor.

A multimeter consists of voltmeter, current meter and ohmmeter.

Sensitivity of a voltmeter is expressed as Ohms/Volt.

If a low voltage is measure on a higher scale of a voltmeter, the measurement would have low accuracy low resolution an low precision.

The disadvantage associated with an electro dynamic instrument are first it consumes more power second it has a low torque to

weight ration and third is its frequency range is low.

The simplest and most convenient form of detector used in a Wheatstone Bridge for audio frequency range is a pair of headphones
Inductance is measured in terms of capacitance and resistance by Anderson Bridge.

The potentiometer wire should have high specific resitance and low temperature coefficient.

Sensitivity of a potentiometer can be increased by increasing the length of potentiometer wire.

All About Electromagnetic Induction Facts and Tutorials

2012-02-09T05:54:00.000-08:00

Key Facts of Electromagnetic Induction

When a magnetic core is magnetized in a strong magnetic field, it retains magnetism after the magnetic force has been withdrawn. This phenomenon of lagging of induction flux density behind the magnetizing force is known as magnetic hysteresis. Moreover the same path is not followed during magnetization and demagnetization processes.

A Degaussing is the process of the demagnetizing metallic part.

Hysteresis can be reduced by the using grain oriented silicon steel.

According to Lenz's law the direction of induced electro motive force and hence current always opposes the cause producing it.

The time constant of an inductive circuit is defined as the ratio of L/R.

Air gap in the iron core of an inductive prevents linear law.

Sparking occurs when a load is switched off because the circuit has high inductance.

The growth of currents is an inductive circuit follows exponential law.

The mutual inductance of two coils is maximum when the coils are touching each other.

The coupling coefficient denotes the degree of magnetic linkage.

In electrical machines laminated cores are used with a view to reducing eddy current loss.

It is difficult to magnetize steel because of its low permeability.

Good Smoothing factor of a coil depends on the inductance of the coil.

The effect of the inductance of a coil on a constant direct current is that it does not effect the constant direct current.

The law that induces emf and current always opposes the cause producing them was discovered by the Lenz.

Leakage factor is more than unity.

A collapsing field around a coil tends to oppose the decay of coil current.

A conductor of length L has a current passing through it, when it is placed parallel to a strong magnetic field. The force experienced by the conductor will be zero.

The left hand rule, thumb correlates current, magnetic field and direction of force on a conductor.

While comparing magnetic and electric circuits, the flux of magnetic circuit is compared with the current electric circuit.

Whenever a conductor cuts magnetic flux. An emf is induced in that conductor. This statement is due to Faraday's law.

While comparing magnetic and electric circuits, the point of dissimilarity exists while considering is flux and current flow.

Current Electricity Flow of Electrons Engineering Tutorials

2012-02-01T01:47:00.000-08:00

The Nature of Electricity
The modern theory defines matter as electrical in nature. All matter is made up of extremely small particles called molecules, each of which has the properties of matter of which it is a constituent. The molecules, in turn are made up of atoms, which are the smallest units of several elements. An atom consists of central nucleus of positive charge around which small negatively charged particles, called electrons, revolve in different paths or orbits.

Free Electrons
The electrons which can be easily removed or detached from an atom are called free electrons.
In metals, the atom lie very close together in regular formed crystal lattice. The nearness of one atom to another causes the electron in the outer orbit or valence electrons of each atom to be attracted by the nucleus is relatively weak. As a result, a large number of electrons are free to drift about interatomic space from atom to atom. These are called free electrons. The free electrons can be easily removed by applying a small amount of external energy.

Charge
A body is said to be charged if it has either excess or deficit of electrons from normal due share. If an electron is freed from a neutral atom, the proton predominate and the atom is said to posses a positive electric charge.

Unit
The unit of charge is coulomb and 1 coulomb is equal to charge on 628 by 10 to the power of 16. We say that a body has a positive discharge of ano coulomb, it means that it has a deficit of 628 by to the power of 16 electrons from normal due share.

Electric Potential
It is a measure of the density and sign of the electric charge at a point relative to that at some time. Thus electric potential, like electric charges and electric current is a phenomenon of displaced charges that exist in matter. For example, consider a copper rod of six meters length having the same number of electrons and protons distributed uniformly throughout.
If by some means, such as intercepting the flux in a magnetic field, one billion electrons can be shifted towards one end of the rod, that end will posses positive charge. The two ends of rod will have a different of potential. Work has been done to create this difference of potential energy.

Nucleus
It is the central part of an atom and contains protons and neutrons. A proton is positively charged particle while the neutron has nearly the same mass as proton, but has no charge. Therefore, the nucleus of an atom is positively charged. The sum of protons and neutrons constitute the entire weight of an atom and is called its atomic weight, it is because the particles in the extra nucleus has negligible weight as compared to protons or neutrons.

Extra Nucleus
It is the outer part of an atom and contains electrons only. An electron is a negatively charged particle having negligible mass. The charge on an electron is equal but opposite to that on a proton. Also, the number of electrons is equal to the number of protons in an atom under ordinary conditions. Therefore, an atom is neutral as a whole. The number of electrons or protons in an atom is called its atomic number.

All About Electrical Relays, Principles, Classification and Requirements

2012-01-22T04:31:00.000-08:00

Protective relays
Relay is a device by means of which an electric circuit can be controlled by the change in the same circuit or in other circuit. The primary function of the protective relay is to sense the fault in the system, compare the signal so obtained with the reference signal under normal conditions of operation and amplify the error signal such that the trip coil of the circuit breaker is energized and faulty section of the system is disconnected from the rest of the system.Under normal conditions of the system, a protective relay is required to keep itself alert such that in case of any emergency, the action may be taken almost instantneously.It should remain silent under normal condition. Under certain operating condition, the power system components are required to carry more than rated current on a temporary basis. During peak load condition, the power system components arc intentionally over-loaded. Under such conditions of operation, often known as abnormal condition, it is not necessary to disconnect the section from the system. When the operation parameters are unduly strained, the protective relays are required to energize the alarms such that proper precautions are taken.

The Basic Principles of Relays
In electromechanical relays, there are one or more coils, movable elements, contact system, etc. The operation of such relays depends on whether the operating torque/force is greater than the restraining torque/force.The relay operates, if the net force, F in equation given below is positive. Where F is the net force, Fo is the operating force and Fr is the restraining force. In other words, the relay operates only if the operating force is greater than the restraining force. In electromechanical relays, the operating torque is produced by electromagnetic attraction/electromagnetic induction/thermal effects of electric current. The restraining torque is given by springs.

The Classification of Relays
Protective relays are classified as follows according to their construction and the principle of operation.
1. Electromagnetic relays These are actuated by Direct current or Alternating current quantities.
2. Electomagnetic induction relays
3. Electothermal relays
4. Static relays these employ transistors or magnetic amplifiers to obtain the operating characteristic.
5. Electrodynamic relays these are operate on the same principle as moving coil instruments.
6. Under-voltage, under-current and under-power relays.
7. Over-voltage, over-current and over-power relays
8. Direntional or reverse current relays
9. Differential relays
10. Distance relays

The Basic Requirements of Protective System
The efficient protective relaying system should posses the following characteristics:
1. Speed
Minimum voltage and minimum fault time operate.
2. Selectivity
Maximum continuity of service by disconnecting the faulty part of the system.
3. Sensitivity
Capability of operating reliably under the actual desired conditions.

Protective Relays
These are the devices that detect abnormal conditions in electrical circuits by measuring the electrical quantities which are different under normal and faulty conditions. Due to abnormal conditions, voltage, current, phase and frequency may change. After detecting the fault, the relay operates to complete the trip circuit which results in the opening of the circuit breaker and isolating the faulty circuit.

All About Electrolysis and Batteries Facts and Tutorials

2012-01-14T00:23:00.000-08:00

1. The two main defects of the primary cells are local action and polarization.
2. Local action in the primary cell can be rectified by amalgamating the zinc electrode with mercury.
3. One factor affecting voltages of the primary cell is the types of plates and electrolyte.
4. Distilled or approved water is used in electrolytes because it prevents or slows down local action.
5. In electroplating, the positive electrode is called the anode.
6. The mass of an ion liberated at an electrode is directly proportional to the quantity of electricity which passes through the electrolyte. This statement is associated with laws of electrolysis.
7. The mass of material deposited over an electrode is proportional to quantity of electricity and electro chemical equivalent.
8. The condition of a secondary cell can be determined by the terminal voltage and strength of the electrolyte.
9. Nickle-cadium dry cell is becoming popular in power supplies for electronic calculators because it is rechargeable.
10. One advantage of a secondary cell is that it can be recharged.
11. Cell are connected in parallel to increase the current capacity.
12. Cells are connected in series to increase voltage output.
13. To obtain a high voltage of about 1.9 volts from a dry cell on would use magnesium cell.
14. While charging a battery, charge the battery in an airy room, remove the vent plugs during charging, keep flames etc. away from the battery and keep the charging current rate not more that 3 to 6 amperes.
15. If the internal resistance of a discharged battery is more it is not desirable to leave a lead storage battery in a discharged state for a long time mainly because plates will become sulphated.
16. To keep the terminals of a lead acid storage battery free from corrosion, it si advisable to keep the electrolyte level low.
17. If a sixty ampere hours battery has sixty seven ampere discharge rate, it will provide a current of six amperes for ten hours.
18. The ampere hour capacity of battery depends on the area of the plates.
19. Electrolyte of a storage battery is formed by adding suphuric acid to water.
20. Other types of accumulators besides the lead acid type are nickle cadmium batteries.
21. Electro-chemical equivalent is mass of the element liberated per unit of quantity of hydrogen.
22. Impurities in an electrolyte can cause an internal short circuit condition called local action.
23. The action of a dry cell is to change chemical action to electrical energy.
24. Polarization in dry cell can be got rid of by chemical means.
25. Gassing occurs in the process of charging an accurnuiator.

Terms used in Electrolysis

Anode
The plate or electrode through which the current enters the electrolyte or it may be defined as the plate or electrode connected to the positive terminal of supply.

Anions
The ions having negative charge are known as anions.

Atom
An atom is the smallest particle of matter which takes part in a chemical action.

Atomic weight
The atomic weight of an element is the relative weight of its atom compared with that of an atom of hydrogen. The atomic weight of H atom is taken as unity.

Cathode
The plate or electrode through which the current leaving the electrolyte or the plates connected to the negative terminal of supply mains.

Cations
The ions having positive charge are known as cations.

Chemical equivalent
The chemical equivalent of an element is the mass which is chemically equivalent to a unit mass of hydrogen.

Ions
When the current is passed through electrolyte, the electrolyte gets chemically decomposed, molecules of the electrolyte splits up into two parts known an ions.

Molecule
The molecule is the smallest particle of any substance which is capable of separate existence in a chemical form.

Valency
The valency of an element is the number of hydrogen atoms with which it will combine or with which it will replace in a compound.

Things You Should Know About Direct Current Generator Tutorials

2012-01-05T06:03:00.000-08:00

The Definition
We know that Direct Current Generator is a machine which converts the mechanical energy into electrical energy. The generator is usually driven by a steam engine or a diesel engine or an electric motor which are called prime movers.

The Principle
The principle of Direct Current Generator is it works on the principle of Faraday's Laws of electromagnetic induction. According to this law the conductors or armature are rotated in the magnetic field and electro magnetic force is induced in these conductors which is collected from the commutators fitted on the shaft of armature.

The Loop
The simple loop of a Direct Current Generator when the plane of the coil is at right angles to the lines of flux, the flux linked with the coil is maximum but the rate of change of flux linkage is minimum. As coil continues to rotate further, the rate of change of flux linkage increases, till it attains maximum value of 90 degree to 180 degree, the flux linked with the coil gradually increases resulting in decrease in induced electro motive force till it reduces to zero at 180 degree. A reversal of the trend occurs during next half revolution. For unidirectional current, the ends of the coil are connected commutation whose function is to reverse the connections to the rotating coil through fixed brushes and to collect the electro motive in one direction.

Four Reasons for failure of a generator to build voltage:
1.Defective contact of brushes with conmmutator due to dirt, insufficient pressure, tight brushes, dirty or rough commutators or projecting intersegment micas.
2. High resistance or open circuit in the shunt field circuit, faulty contact or burnt resistance in shunt regulators.
3. Loss of residual magnetism.
4. Reverse field connection or reversed speed.

Ten Reasons for sparking and Bad Bommutations:
1. Overload
2. Projecting intersegment micas.
3. Earth fault on armature
4. Armature short circuit
5. Incorrect brush position
6. Wrong grade of brushes
7. Reversed interpole coils
8. Brushes not properly bedded
9. Brushes not equally spaced
10. Worn Brushes

Question and answer about D.C. Generator
1. The armature of a DC generator is laminated to reduce eddy current loss.
2. In a shunt generator the voltage built up is generally restricted by the saturation of iron.
3. Copper loss in DC generators varies with load.
4. Full load efficiency of the generators is 92.51 percent.
5. Shunt generators are preferred for parallel operations.
6. In DC generator the ripples in the direct electro motive force generated are reduced by using commutator with large number of segments.
7. The functions of an interpole is to neutralize crossfield of armature reaction and obtain ideal commutation.
8. Equalizer connection are required when paralleling two compound generators.
9. A simple method of increasing the voltage of DC generator is to increase the speed of rotation.
10. In the commutation process it is the current which is getting reversed.

25 Tips You Need To Know About Current Electricity Engineering

2011-12-28T05:49:00.000-08:00

1. The curve representing Ohm's law in linear.
2. The condition in Ohm's Law is that the temperature should remain constant.
3. The Ohm's Law can be applied with certain reservations to electrolytes.
4. The presence of an electric current is made known by the effects produced.
5. An electric current can neither be seen nor touched.
6. Three important effects produced by the presence of a current heating, magnetic and electric shock.
7. Thermistor has negative coefficient of resistance.
8. International ohm is defined in terms of resistance of a column of mercury.
9. Resistors commonly used in power circuits are wire wound resistors.
10. When current flows through a heater coil it glows but the supply wiring does not glow because the resistance of heater coil is more than that of supply wires.
11. If the voltage applied across an electric press is reduced by 50 percent, the power consumed by the press will be reduced by is 25 percent.
12. In a parallel circuit the potential difference across the resistance is always constant.
13. In a series circuit the current is constant.
14. Voltage applied across a circuit acts as a force.
15. The resistance of carbon filament in carbon-filament lamps increases when its temperature is decreased.
16. The heating effect of current has an undesirable side effect in a vacuum cleaner.
17. When current flows in a conductor, the heat is produced because of inter atomic collision.
18. The temperature coefficient of a conductor is defined as the increase in resistance per ohm pwer degree centigrade.
19. The value of Joule's mechanical equivalent of heat,is equal of 4.2 Joules per calorie.
20. It was experimentally found by James Precott Joule that the heat produced in a current carrying conductor is proportional to the square of current.
21. The resistance of a conductor increases when its temperature is increased.
22. The specific resistance, depends upon the nature of the material of the conductor only.
23. Resistance of a conductor increases when its length increases.
24. The resistance of conductor is the hindrance by which the conductor opposes the flow of the current.
25. The minimum requirements to cause the flow of current are a voltage source and a conductor

All About Capacitors Electrostatics and Electric Lines of Force

2011-12-20T04:16:00.000-08:00

Some Important Characteristics of Capacitors
1.The current through capacitor is zero, if the voltage across it is not changing with time.
2. A capacitor is sort of open circuit to direct current.
3. The capacitor never dissipates energy but only stores it.
4. A capacitor resits an abrupt change in voltage across it.
5. A finite amount of energy can be stored in a capacitor even if the current through capacitor is zero, such as when the voltage across it is constant.
6. It is impossible to change the voltage across a capacitor by a finite amount in zero time, for this requires infinite current through the capacitor.

Electrostatics Question and Answer
1. Relative permitivity of vacuum is unity.
2. In the electric field, the potential is the work done in joules to bring positive charge of one coulomb from infinity to that point.
3. The unit of field intensity is newtons/coulomb.
4. Coulomb's law for the force between electric charges most closely resemble with Newton's law of gravitation.
5. Mica medium has highest value of dielectric strength.
6. The maximum value of potential gradient in cable occurs in conductor.
7.A region around a stationary electric charge has electric field.
8. Inside a hollow spherical conductor electric field is zero.
9. The effect of the dielectric is to reduce the working voltage.
10. Electrolytic capacitor is the most commonly used type but it has two disadvantages, namely low insulation resistance and suitable for Direct current only has high capacitance and low insulation resistance.
11. In a radio a gang condenser is a type of air capacitor.
12. A sphere of one metre redius can attain a maximum potential of three kilo volt.
13.The power dissipated in a pure capacitor is zero.
14. In a capacitor the eletric charge is stored in dielectric.
15. One farad is one coulomb per volt.
16. If a dielectri is placed in an electric field, the field strength decreases.
17. If the medium of a parallel plate capacitor consists of mica and air, the capacitance is increased by increasing the area of plates.
18. A capacitor with capacitance is charged through a resistance. The time constant of the charging
circuit is given by RC.

Properties of Electric Lines of Forces
A line of force is supposed to start or emanate, from a unit with a positive charge. A line of force does not form closed loop unlike a magnetic line of force. The line of force is always normal to the surface of the body at the point from where they originate or terminate. No two lines of force can across each other. An electric line of force in the same direction repel each other and those in opposite direction attract each other. There will be neutral point in this case between the two sphere. An electric line of force has a tendecy to take an easy path.

Transmission and Distribution Lines Key Facts and Tutorials

2011-12-16T01:19:00.000-08:00

Key Facts and Tutorials On Electrical and Distribution Lines

1. The economical section of a feeder can be obtain by applying Kelvin's law.
2. There should be be no break in the neutral, which is usually earthed at the supply end, of a two wire Alternating Current distribution system because excess current protection would be affected.
3. In actual practice the potential at the two feeding points is unequal. To calculate the voltage drop, the difference in potential is converted into ampere metres and the moments of the lower feeding point start from this initial value.
4. Uniformly loaded distribution fed at equal potential from both ends is treated like the distributor because the voltage drop is exactly halved.
5. Voltage drop in a uniformly loaded distributor fed at once end is calculated by assuming the whole of the load concentrated at middle point.
6. For Alternating current distribution the power factor of the load has to be taken into consideration and the calculations become cumbersome. The approximate method which gives results with in plus or minus five percent of the actual voltage drop involves calculating the centre of gravity of the load, resistance and reactance per double run and average power factor.
7. To determine the distribution of load at the point of minimum potential, the moments in ampere metres about of the feeding points must be equal to the moment in ampere metres about the other feeding point.
8.At the point of minimal potential in a distributor fed from both ends, the load at the point is supplied from right and left hand feeding points.
9. With point loads in a distributor fed at both ends, in order to determine the maximum voltages drop it is necessary to know the point of minimum voltage.
10. For a three wire Direct Current distributor fed at one end, if the total voltage drop in the neutral is positive it is added to the positive drop and deducted from the negative drop.

Limitation of high transmission voltage
a. Increased cost of line support
For high transmission voltage, the insulation required between the conductors and the earthed tower is more. This increases the cost of line supports.
b. High towers:
For high transmission voltage, the clearance between conductors and groundo should be more. Therefore, higher lower is required.
c. Longer cross arms:
FOr higher transmission voltage, distance between the conductors should be more. Therefore, longer arms are required.

World's Largest Nuclear Power Plant Located in Japan

2011-12-12T07:44:00.000-08:00

The Kashiwazaki-Kariwa Nuclear Power Plant is the World largest Nuclear Power Plant located at Japan the land in the towns of Kashiwazaki and Karina in Niigata Prefecture, Japan it has
4.2 square kilometer or equivalent of 1,038 acres site. The owner of the nuclear power plant is The Tokyo Electric Power Company or TEPCO. has an approximately 15 miles from the epicenter. There are seven units in which are all lined up along the coast line. The total capacity of the seven unit Nuclear Power plant is 8,212 mega watts since 1997 this is the largest station of its kind in the world. We know that this power station can produces sufficient energy that could cover on the domestic electricity use of about 16 million households.

Power Plant on an Earthquake Fault Line?
The Kashiwazaki-Kariwa nuclear power plant, closed since Monday following the major earthquake in the north of Japan is now known to be placed directly above a significant geological fault line.

Iran’s nuclear negotiator visits world’s largest power-plant
Iranian Supreme National Security Council Secretary and top nuclear negotiator Saeed Jalili has visited the world’s largest power plant in Japan.

Global Nuclear Power Outlook and Opportunities
Is any nuclear technology designed to extract usable energy from atomic nuclei via controlled nuclear reactions. The only method in use today is through nuclear fission, though other methods might one day include nuclear fusion and radioactive decay

source

All About Magnetism and Electromagnetism How It Works

2011-12-01T04:46:00.000-08:00

All About Magnetism and Electromagnetism How it works Tutorials
Magnet
A magnet is a substance that attracts pieces of iron. The phenomenon by which this attraction takes place is called magnetism.

Magnets are two types
Natural Magnets
The natural magnets are those iron ores which are obtained from mine and have the property of attracting iron pieces naturally.

Artificial magnets
The artificial magnets are those which are created by artificial means. An artificial magnet can be further divided into two types are temporary magnets and permanent magnets.

Temporary magnets
A temporary magnet is that in which magnetism remains temporarily. If a wire is wound on a soft iron piece and direct current is passed through the wire, then soft iron piece becomes a temporary magnet. It is because the iron piece will retain magnetism so long as the current is flowing.

A Permanent magnets are made from steel which is in general harder than soft iron apart from steel, alloys like cobalt steel, tungsten steel, etc. are also used as permanent magnets. These are used in Direct current machines to create magnetic flux, electrical instruments, moving coil loudspeaker etc.

Properties of Magnet
1. A magnet always attracts iron and its alloys
2. The magnet has two poles and when it is freely suspended it comes to rest pointing north and south directions. The end which points towards north is known as North-pole and the other which points toward south is known as South-Pole. The attracting power of the magnet is concentrated around two points one each at end ends.
3. Like poles repel and unlike poles attact each other.
4. If a magnet is broken into pieces, each pieces becomes and independent magnet.
5. A magnet can import its properties to any magnetic material.

Magnetic effect of electric current
When and electric current flows through a conductor, a magnetic field is set up all along the length of the conductor. In this connection following are the important points worth noting.
1. The magnetic lines of force are circular in a plane perpendicular to the current.
2. The field near the conductor is stronger and becomes weaker as we go away from the conductor.
3. The magnetic field becomes stronger if current is increased and vice-versa.
4. The direction of the field is reversed it current is reversed.

Facts of Magnetism and Electromagnetism
1. A magnet is a piece of iron or other magnetic material which can attract small pieces of thesematerial towards it.
2. A freely suspended magnet always rests in north south direction.
3. A natural magnet is called lodestone.
4. A magnet is able to attract nickel, cobalt and steel.
5. Externally, magnetic line of force travels north to south.
6. A material commonly used for shielding or screening magnetism is soft iron.
7. Magnetism is the property of certain materials of attracting small iron pieces toward them.
8. The magnetism that remains in a magnet after the magentising force has been removed is called its residual.
9. Iron becomes magnetized by induction when it is near to one end of a magnet.
10. Magnetic lines of force are called flux.

All About Electronics Binary Numbers Tutorials

2011-11-20T04:43:00.000-08:00

In digital system, however, only the digits 0 and 1 are used. This system is also known as binary system. It has a radix of 2. The binary system is used because digital circuits operate with square wave pulse waveforms that have only two amplitudes HIGH and LOW or ON and OFF.
There are many application of digital electronics in addition to the natural function of counting pulses. Even audio and video information can be converted into digital form for transmitting long distances and then reconverted to pulses. The advantage of digital circuits is the excellent signal to noise ratio.Binary to Decimal Conversion The process of converting from binary to decimal just involves counting the place values for base 2. From right to left, they are 1,2,4,8,16, 32,64, 128. etc. all in power of 2.

Binary Logic Gates
Logic gates are circuits the output voltage of which can be predicted from the conditions at the input.

Electronics Address
The rules of binary additions are:
0 + 0 = 0
0 + 1 = 1
1 + 0 = 1
We cannot have 1 + 1 = 2 in binary system. It is 1 + 1 = 0 plus carry of 1 to the next position towards left. This addition with carry in can take place in any column except the 1's place.

Half Address
Electronics address are constructed from logic gates to add binary numbers. A half adder combines 0 and 1 with carry of 1 to the next place, if required, but it has no terminal for carry in.

The Full Address
A full address has the provision for carry in and carry out. A full adder if formed by using two half adders and an OR gate. The output of the OR gate forms the carry out output. The full adder is for binary additions in all places except the 1's place.

FLIP FLOP
The flip flop or FF is a basic digital circuit having memory characteristic that can be used to store information. The circuit is bistable multivibrator that stays in one state until switched to the opposite state. The two outputs Q and Q are always opposite as HIGH and LOW logic levels.
The main types of flip flops are the R_S, with set and reset input terminals, D, and J_K. Clock input pulses are often used in the toggle mode, in which the Q and Q outputs are reversed by each clock input puslse.

Digital Electronics Question and Answer
1. Binary 111111 represents Decimal 51
2. Binary 1000 when subtracted from binary 1111, the result will be 111
3. Decimal 0.875 is represented in binary system as .111
4. The bolean expression for AND gates is A.B = Y
5. Integrated circuit logic gates contain the properties are resistors, diodes bipolar junction transistor
6. The abbreviation DTL stands for diode transistor logic
7. The basic DTL configuration is NAND gate
8. The schottky TTL, a Schottky diode is used primarily to
9. A schottky diode has no minority carriers and very low voltage drop in forward direction
10. In a RS flip flop no change occurs during disabled mode
11. In a digital counter the number of flips is equal to the number of bits required in the final binary count.
12. A temporary memory is destroyed when power is switch off
13. PROM is programmable read only memory
14. A digital voltage has anlog input and digital output
15. LCD display represents liquid crystal display

Current Interrupter Tutorials

2011-11-10T05:53:00.000-08:00

Current Interrupter Tutorials Facts, Definitions, Uses Etc.

Circuit Breaker
An electromagnetic device that opens a circuit automatically when current exceeds a predermined value. It is capable of interrupting large values of fault power MVA resulting from the faults on the power system. It consists of current carrying contacts called electrodes which, under predetermined conditions, separate to interrupt the circuit. An arc is struck between them when the contacts are separated. This arc is extinquished either by lengthening the arc, cooling the arc, or splitting the arc. Due to this, the arc resistance increases resulting in the system voltage becoming unable to maintain the arc and the arc gets extinguised.

HRC Fuse
High Rupturing Capacity cartridge fuse is a good interrupting device because it gives a fast fault clearing and exhibits property of cut-off. It is useful in low and medium voltage installation to provide overload and short-circuit protection. The fuse element is of copper alloyed with tin. Its characteristics vary with the type of material and the shape of fuse element. The rated current of the fuse is the current which it can carry continously without deterioration.

Switchgear
The name given to a family of devices covering a wide range of equipment concerned with switching and interrupting the currents during normal and abnormal conditions. The equipment associated with controlling, protecting, regulating and measuring also belong to the switchgear family. It includes switches, fuses, Circuit breaker, isolator, relays, Control panel, metering panels lighting arresters, Current transformer, Potential transformer, and other associated items. The circuit breakers are assited by other components of the protective scheme. A switch is used for opening and closing the circuit. Fuse is used for over-current protection. The purpose of switching and protection is served by the swithgear. A circuit breaker is the switching and interrupting device in a switchegear.

Reactors
The purpose, of reactors incorporated in circuit breakers is to limit the short-circuit current flowing to a safe value thus providing protection of instruments. The concist of large coils of high self-inductance and very low resistance. Main type of reactors are magnetically shielded reactor, and the shielded reactor.

Answer all Frequent Questions About Circuit Breaker
1. The function of protective relay in a circuit breaker is to close the contacts when the actuating quantity reaches a certain predetermined value.
2. Low voltage circuit breakers have rated voltages of less than 1000 volts.
3. When A high voltage Alternating current circuit breaker is tested for endurance, it is tested for at least 1000 opening closing operations.
4. For high voltage Alternating Current circuit breaker, the rated short circuit current is passed for 3 three second.
5. Vacuum is not a type of the contactor for circuit breaker.

Current Interrupter Tutorials

Network Theorem Kirchoff's Law Tutorials

2011-11-03T19:24:00.000-07:00

Kirchoff's Law Facts and tutorials

Kirchoff's Current Law (KCL)
In any electrical network. The algebraic sum of the currents meeting at a point or junction is zero. Here it is assumed that incoming current to be positive and outgoing current to be negative.

Kirchoff's Voltage Law (KVL)
The algebraic sum of the products of currents and resistance in each of the conductors in any closed path or mesh in a network plus the algebraic sum of the electromotive force in the path is zero.

Sign Conventions for Kirchoff's Law

A rise in voltage shall be given a plus sign and fall in voltage drop shall be given a negative voltage sign.
In a resistance if we traverse in the direction of current. It is a voltage drop. This is because the current flows from higher potential to lower potential. This is voltage drop. It is given to be a negative voltage sign.
In a resistance if we go in the direction, opposite to direction of flow of current, we are going from lower potential to higher potential. Going from lower to higher potential means voltage rise and shall be given a positive voltage sign.
In a battery if we go from negative voltage sign terminal of battery to positive voltage sign this is voltage rise. This shall be given a positive voltage sign.
In a battery if we go from positive voltage sign terminal of a battery to negative voltage sign terminal, this is voltage drop. It should be given a negative voltage sign.

Method to solve circuits by kirchoff's Law

Draw a large clear diagram of the network to be solved showing the values of all resistors and the polarity and values of all sources of electromotive force letter the nodes and number of meshes.
Arbitrarily choose direction for the currents in each branches. There is no point in wasting time for trying to indicate the true current directions since, in the majority of the cases, it is quite impossible to tell.
Place plus and minus signs on each resistors to indicate the direction of the potential difference across it. These potential differences must be constant with the directions of the assumed branch currents.
Write an equation for each in the network, using Kirchoff's second law, traversing the meshes in the clock wise direction.
Solve the resulting simultaneous equations.

Take note that, it should be noted that Kirchoff's law are applicable both direct current and alternating current. Voltage and current, However in the case of alternating current and voltages any electromotive force or self-inductance that existing across a capacitor should also be taken into account.

Free pdf file for network Theorem
The fundamental laws that govern electric circuits are the Ohm’s Law and the Kirchoff’s
Laws.