Compact Fluorescent Lamp (CFL)

Compact Fluorescent Lamp (CFL) The compact fluorescent lamps are becoming very useful nowadays, because of consumption of power, cost, longer life, attractive look, smooth light and low maintenance. These lamps are available in different sizes and designs. They have single rod, double rod, triple rod or spiral rod. These lamps are available in different power […]

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Mercury vapour lamp

Mercury vapour lamp On the basis of pressure inside the discharge tube, the mercury vapour lamps are classified as High pressure mercury vapour lamp and Low pressure mercury vapour lamp. High pressure mercury vapour lamps are classified as: 1. MA type (Mercury vapour lamp with auxiliary electrode) These are operated at 220 ‐ 250 volt, […]

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Incandescent lamp – There are two types. 1. Vacuum type lamp and 2. Gas filled type lamp

Incandescent lamp The filament of this lamp is heated up to the incandescent stage of heat. So these types of lamps are called as incandescent lamps. There are two types. 1. Vacuum type lamp and 2. Gas filled type lamp In this type of lamp, the sphere shaped glass cover is used. The glass stem […]

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Laws of illumination – Inverse square law, Lambert’s cosine law, Light, Electrical method of producing light

Laws of illumination The illumination on a surface depends upon the luminous intensity, distance between the source and surface and the direction of rays of light. It is governed by following laws. 1. Inverse square law 2. Lambert’s cosine law Inverse square law It states that the illumination of a surface is inversely proportional to […]

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Illumination – Introduction, Important terms in illumination

Introduction Almost all human activities are based on light. Natural light is obtained from the sun. Artificial light plays an important role in our everyday life. In places where natural light is not available, artificial light is obtained by electric lamps. Lighting plays an important role because of its belief, consistency, simple control and low […]

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Three phase cable – they are a. Belted cable up to 11 KV, b. Screened cable 22KV to 66 KV, c. Pressure cable above 66 KV

Three phase cable Commonly, underground cables are used to transmit three phase power supply. For three phase service, the following cables are used. a. Belted cable up to 11 KV b. Screened cable 22KV to 66 KV c. Pressure cable above 66 KV a. Belted cable up to 11 KV The crosssection view of the […]

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Classification of cables – According to the rating of voltage the cables, According to insulation, cables, According to number of conductors, cables

Classification of cables a. According to the rating of voltage the cables are classified into i. Low tension cables up to 1 KV ii. High tension cable up to 11KV iii. Super tension cables 22 KV to 33KV iv. Extra high-tension cables 33KV to 66 KV v. Oil filled cables 66KV to 132 KV vi. […]

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Power distribution system, Feeder line, Distributor, Classification of distribution system, Service lines

Power distribution system The medium voltage transformer using transmission lines are reduced by step down transformer (415V, or 240V) are used to the consumer. This system includes the feeder lines, distributors and service mains. Feeder line The feeder line is nothing but similar as power transmission conductors. It connects the power from sub-station and power […]

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Types of insulators – they are i) Pin type insulator, ii ) Suspension insulators {a. Hewlett suspension type b. Cemented cap type c. Core and link type}, iii. Strain insulator, iv. Shackle insulator, v. Stay type insulator

Types of insulators i. Pin type insulator ii. Suspension insulators a. Hewlett suspension type b. Cemented cap type c. Core and link type iii. Strain insulator iv. Shackle insulator v. Stay type insulator i. Pin type insulator This type of insulator is fixed in the crossing arm of the pole. The conductor is placed in […]

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Line insulators – Line insulators, Properties of insulators, Line insulator materials

Line insulators The overhead line conductors should be supported with the poles or towers by means of insulators. These insulators act as supports in order to avoid any leakage of current from the conductor to earth. Properties of insulators Here are some of the properties of line insulators i. Mechanical strength should be very high. […]

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Types of overhead lines – Short transmission lines, Medium transmission lines, Long transmission lines, Guarding

Types of overhead lines The transmission line has three parameters, resistance, inductance and capacitance distributed uniformly along the whole length of the line. The resistance and inductance forms series impedance. The capacitance existing between conductor for single phase line and a conductor, to neutralize the three-phase line, forms a shunt path through the length of […]

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Effects of transmission – Skin effect, Corona: Factors affecting corona, Advantages of corona, Disadvantages of corona

Effects of transmission 1. Skin effect When an alternating current flows through a conductor, a flux will be produced in it. This flux will be higher at the center of the conductor than outer surface. The high reactance of center area causes the alternating current to flow near the surface of the conductor. This is […]

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Types of poles – Wooden poles, Concrete poles, Tubular steel poles, Latticed steel tower

Types of poles Line supports or the poles which hold the conductors to a height they are above the ground level. In general, four types of poles are used, depending on the size and shape of the conductor used. i. Wooden poles ii. Concrete poles iii. Tubular steel poles iv. Latticed steel tower i. Wooden […]

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Overhead line transmission – Main components used in overhead lines, Transmission line conductors, Properties of conductors

Overhead line transmission The overhead lines are used to transmit electricity from power plants to consumers. A network of electrical power lines are used to transmit the electricity over a geographic area is called power grid. Main components used in overhead lines i. Electric conductors ii. Poles and towers iii. Insulators iv. Cross arm that […]

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Alternative transmission – Primary transmission, Secondary transmission, Advantages of AC transmission, Disadvantages of AC transmission

Alternative transmission From the power generating stations, a large amount of AC supply is produced and is transmitted through transmission lines. The layout of a typical AC power supply system. The transmission is done caried by 3 phase 3 wire and 3 phase 4 wire systems. Other methods are also used for some special reasons. […]

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Direct Transmission – Advantages of DC transmission, Disadvantages of DC transmission

Direct Transmission Let us see the transmission of DC power from the AC power. The single line diagram of high voltage direct current transmission is given in Alternative current is generated and stepped up to high voltage through the sending end transformer. This high voltage alternating current is converted to the direct current by a […]

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