Electrical Engineering

               We know, the universe consists of five big natural energy sources like water, land, Air, fire and  space. The Sixth important energy developed by human is called "Electricity". In this modern world, for our day to day life the electricity plays a vital role. Simply to say, even man lives without food but not lives without Electricity. Because in our life, the electrical goods play an important role.Hence the students must know about this source and how it is applied.

Electricity is one type of energy. All matter whether solid, liquid or, gaseous consists of minute particles known as Atoms. According to modern Research electric current means flow of electron. So we need to know about the Atom.

1.2.        ATOM

It has a hard central core known as nucleus. It contains two type of particles one is known as proton and carries positive charge. The other is neutron, which is electrically neutral, i.e. it carries no charge. Around the nucleus in elliptical orbit the electrons one revolving. Electrons cany the negative charge. The number of electron are number of protons in a atom are equal. So the atom is electrically neutral. The number of protons in the nucleus of atom gives the atomic number. The total numbers of neutron and proton are known as atomic weight. Because negligible weight of the electron is not taken to calculate atomic weight.

1.3.        METHODS OF ELECTRICITY PRODUCTS

An electricity is produced by the extraction of electrons from an atom. The energies which are used to produce an electricity are (i) Friction (ii) Light (iii) Heat (iv) Pressure (v) Chemical Action (vi) magnetism.

1.3.1. Electricity due to friction

Due to the friction of two material, the electrons come out from one material to join with the other material. The material which looses the electron gets +ve charge and the material attracted the electron gets -ve charge. This type of electricity is called Static Electricity.

Ex. Materials like Glass, Rubber, Wax, Silk, Reyon, Nylon.

1.3.2 Electricity due to light

When the light falls on the material, the electrons emitted from the surface and producing the flow of current. For this purpose Photocell is used. Photo cell is used to convert the light energy into current. The materials which emitted electron due to the light fall on the surface are "photo sensitive metal.¹⁵

Ex. Sodium, Potassium, Lithium, Cesium.

1.3.3 Electricity due to Pressure

Electrons in the outermost orbit of an atom is extracted due to the pressure applied to an atom and the electricity is produced. This is called "Piezo Electricity". In a telephone, diapharam is pressured by the sound waves. Because of this, Electric Waves are produced depending upon the pressure of sound waves.

1.3.4 Electricity due to Heat

The ends of two metal rods are joined together and this joined part is heating. Due to this the part opposite to the heated place is connected by a Galvanometer and the Electricity is known as the deflection of the pointer.

In the same way, two metal plates are j oined together and is heating, for the purpose of producing electricity. This type is called "Thermo Coupling Method."

For the above four methods, sufficient electricity is not produced and the energy of electricity is also less. Because, the other two methods are used to produce the sufficient electricity with high energy.

1.3.5.Electricity due to chemical action

By using the method of chemical action, electrons are extracted from an atom and producing electricity. This method is used for producing electricity in primary and secondary cells.

Primary cell is used in torch light and the secondary cell is used in cars, motorcycles etc.

1.3.6. Electricity due to Magnetism

In this method Electrons are extracted from an atom due to magnetism. For this purpose generators are used. In generator the energized electricity is produced by the magnetic poles and armature winding.

In our country the requirement of electricity is produced in all the above methods.

In this we have to study about all the power generating stations in Tamilnadu and how the electricity is produced.

1.4. POWER GENERATING PLANTS

Today, there are seven power generating stations are available in our country. By this, approximately 7000 MW current is produced in our country

Types of Power Generating Plants

1.        Hydro Electric Power Plant

2.        Thermal Power Plant

3.        Atomic Power Plant

4.        Gas Power Plant

5.        Diesel Power Plant

6.        Solar Power Plant

7.        Wind-Mill Power Plant

1.4.1. Hydro Electric Power Plant

From the water reservoir, the water is taken through the jaint tubes to the water turbine. For the rotation of turbine, the kinetic energy of water is converted into mechanical energy and is converted into electrical energy by the using of generators.

This type of plant is placed in TamilNadu at Mettur, Kunda, Bicara, Suruliyaru & Kadamparai.

1.4.2.    Thermal Power Plant

Chemical energy is converted into heat energy by burning of coal or lignite in boiler plant. Water in the boiler is converted into steam by heat energy. This steam is flowing through the steam turbine which is connected to the generator and this energy is converted into mechanical energy by the rotation of turbine. The mechanical energy is again converted into electrical energy by the use of generator.

This type of plant is placed in TamilNadu at Ennore. (Chennai), Neyvelli, Tuticorin and Mettur.

Thermal Power Plants play a major role for the requirements of electricity in Tamilnadu

1.4.3.    Atomic Power Plant

By the diffusion of an atom of Uranium or Thorium, to getting more heat. Based on this principle the atomic power plant is working. The heat energy is produced and is used to rotate the steam turbine and this energy is converted into mechanical energy. Hie generator converts the mechanical energy into electrical energy.

This plant is placed in Kalpakkam near Chennai and Tharapur in Rajastan State. Leakage of gas by this plant may cause pollution and affect the health of the people.

1.4.4.    Gas Power Plant

For the rotation of turbine, the underground gas is used. The generator which is connected to the turbine produces the electricity. This plant is placed in Ramanathapuram and Kuthalam.

1.4.5     Diesel Power Plant

This type of plant is used for the place where the continuous requirements of electricity is needed, i.e. in big factories and refrigeration works. The electricity is produced by the generator which is connected to the big diesel engine.

Depending upon the requirements, different capacities of small or large diesel generators are used in hotels, hospitals, Jewelleryshops, cinema theatres, shipyards etc.

1.4.6     Solar Power Plant

For the purpose of minimum production of electricity, this type of plant is placed on the roof of the buildings. In this plant, the electricity is produced by using sun-rays. This is used in houses, hotels, hospitals, traffic signal lights etc.

1.4.7     Wind-Mill Power Plant

The Wind-Mill is rotated by heavy speed of wind. The electricity is produced by the generator which is operated by the wind-mill. This plant is placed at Kayathar in Nellai District and placed at Palladam-Udumalai Pettai Road in Coimbatore District.

1.5. ELECTRICAL SAFETY AND PRECAUTIONS

A man who works in the electrical department must be carefully handled the work without any damage to the equipments and also workers. Because accident may occur heavy loss. He must know all the operations of electrical equipments. Otherwise wrongly handled the equipments will cause heavy loss. Electrical accident may occur only due to carelessness. Due to this, workers will get injured, damaged equipments will cause loss, because the work was stopped. To avoid this, electrical workers must follow the rules and regulations when working.

1.5.1. Electrical Precautions

• Before he use the equipment's, he must know the operation of that equipment's. Electrical connections are made properly according to the definition.
•  Only the trained and efficient person is allowed to operate, testing and repairing the machine.
•  A person works in the electric post and tower post must wear the safety belt and grouse.
•  If the situation is occur, the man who works on the ladder, the other persons helps to capture the ladder for safety. If it is essential, then the post and the ladder must be tied with a rope for safety purpose.
•  After earthing the overhead lines by discharge rod, then the work will continue.
• Check the condition of all the hand tools, supply wires operated in current and also to check the earth wire is in good condition.
• To remove the plug point pin from the socket by the proper way, cannot pul ling the wire.
•  After the main switch is off, fuse wire must be changed. Depending upon the load, sufficient ampere fuse wire is provided.
•  All the hand tools used in electrical works must be insulated.
•  During made up of wiring, switch is always connected in phase line.
•  If any fault occur in the electrical equipment in the houses, it will be checked and repaired after  the equipment is totally disconnected from the supply.
•   Ex. Fan, Grinder, Mixer etc.
•   Safety equipment's existing in the electrical circuit is not removed due to any reasons.
•   If fire occurs in the electrical circuit, immediately the main switch is turned to off position. For extinguishing the fire any one of the following i.e. carbon-di-oxide extinguisher, dry power extinguisher can be used. Soda acid extinguisher is not used at any cost. Water is not used to extinguish the fire because it conducts electricity and cause severe accident.
•  If any person getting electric shock because of touch the electric wire, immediately the supply is disconnected. The person is removed from the wire by the use of dry stick, dry wooden plank and dry cloth etc.
• When the battery is charging in a room, the room must be in a condition to get free air. To avoid dangerous situation, no fire is available near the battery.
•  For producing electrolyte, water is not added to acid. Hydrochloric acid is added in the water  by drop by drop.
•   Sweating hand is not used to switch ON or work on the electric supply. If the person has sweating on the hand continuously, he must wear the glouse.
•   The switch is in OFF position. Before to turn ON the switch to check if anybody is working in that electrical circuit.
• The above points are used for electrical workers and they can be work without any damage.

1.5.2. Electrical Shock

Human body has a electrical conducting property. Without sweating of human body the resistance is approximately 80000(Ohms) and during sweating resistance of the human body is approximately 1000(Ohms). If we touch the current carrying conductor, the current is conducted through our body to earth. So the electrical circuit is closed and we get electric shock due to this, nervous structure, heart, lungs and brain are affected. If the current is heavy, death may occur. Therefore we must know, even though the current is essential,if it is used wrongly, it will cause heavy loss. i.e. death and economical loss.

To prevent this electrical shock, we know about the methods of preventive cares and protective methods for safety precautions.

1.5.3. Preventive method to avoid electric shock

 The Operation of electrical equipment's must be known.

•  Damaged wire is not used for wiring works or electrical connection.
•  The Electrical Instruments used for connections (i.e. switch,plug,pushings) is not having any scratch or breakable, If it is in such a way that it must be replaced by new one.
•  Requirement hand Tools are used in proper way
•  The hand tools are insulated essentially.
•  Proper earthing is provided.
•  If the supply is taken from the socket, only the plug top is used. To avoid, the supply is taken by inserting the wire with stick in the socket.
• Depending upon the load, rated ampere fuse wire is used.
• The electrical equipment is repaired after the main switch is off.
•  For any reason do not operate by overcoming the safety rules.

The electrical shock may be avoided for following the above methods in a proper way.

1.5.4. First Aid

Due to unavoidable reason, a man affects from sudden accident occur or electric shock, he may be treated by first aid method to protect from death, before taken into hospital.

When a person is affected by current shock, first the circuit should be disconnected. If the main switch is nearer put off the switch or using any wooden stick we could disconnect the person from circuit. Then immediately send him to consult a doctor.

If the affected person lose his consciousness, but breathing is normal then looser his clothes and apply cold water on his face and keep him in open air.

If the person does not breath then immediately arrange artificial method of breathing clean his mouth and keep it open.

There are three methods of artificial breathing.

HOLGER NELSON METHOD

In this method the victim should be kept in the bed facing the ground. Fold his hands and keep it in the backside of his head, the helper sitting at his head should massage his back using both hands. This is done with in two seconds.

Mouth to mouth

    In this method the helper pushes air by keeping his mouth on the victim's mouth.By closing his nose then the air fill lungs. So the victim gets artificial respiration.

MOUTH TO MOUTH METHOD

•  Put the victim on a bed-sheet.
•  If his tongue is folded correct it.
•  Using both hands catch his for head and chin.
•   For respiration place your mouth over the mouth of the victim and send an to his body for  respiration.

Through Nose

In this method the helper send air through victim's nose. By closing his mouth the air is blown in his nose till the heart of the victim rises by this way the victim gets artificial respiration. For a child the air blown is half the heart level, compared to adult.