Found 60 Articles for Distribution of Electric Power

The element of the transmission line by which the line conductors are insulated from supports is known as line insulator. The insulators used in the transmission lines are of various types. Some of the important types of insulators are given as follows −Pin Type InsulatorSuspension Type InsulatorStain InsulatorShackle InsulatorPin Type InsulatorsThe pin type insulator is shown in the figure. The pin type insulator is fitted to the cross-arm on the pole. The pin type insulator has a groove on the upper end of the insulator for housing the line conductor. The line conductor passes through this groove and is bounded ... Read More

Corona Effect in Overhead Transmission LineThe phenomenon of violet glow, hissing sound and production of ozone gas in an overhead transmission line is known as corona.When a very high voltage is applied across two conductors of the overhead transmission line whose spacing is large as compared to their diameters. When this applied voltage exceeds a certain value (called critical disruptive voltage), then the conductors are surrounded by a faint violet glow that is known as corona effect.In practice, the corona effect is accompanied by a hissing sound, production of ozone, power loss and radio interference. The higher is the transmission ... Read More

What are Insulators?Insulators are the elements of transmission system which provide necessary insulation between line conductors and supports and hence, prevent any leakage current from the conductors to the earth.The line conductors in the overhead transmission lines should be supported on the poles or towers in such a way that the current from the conductors do not flow to the earth through the supports which means the line conductors must be properly insulated from the supports. This is achieved by using the insulators between the line support and conductors.The commonly used material for manufacturing the insulators of overhead transmission line ... Read More

The transmission voltage for which the cost of conductors, transformers, insulators, switchgears and other terminal apparatus is minimum is called the economical transmission voltage.As we know, if the transmission voltage is increased, the volume of conductor material required for the transmission lines is reduced. Hence, this decreases the expenditure on the conductor material. It is advisable to use the highest possible transmission voltage in order to reduce the expenditure on the conductor material to a minimum. Although, it may be remembered that as the transmission voltage is increased the cost of insulation, transformers, switchgears and other terminal equipment also increases. ... Read More

Underground Electric Transmission SystemThe system of electric power transmission uses underground cables for transmitting the electric power from the generating station to the consumers is known as underground electric transmission system.Underground cables have low visibility and are not affected by bad weather. However, the cost of these cables is comparatively high and their laying process is also time consuming.Types of Underground Transmission SystemBased on the type of supply (i.e. AC or DC) and the number of conductors used, the underground electric transmission system can be classified into the following types −Underground DC SystemTwo-Wire DC SystemTwo-Wire DC System with Mid-Point EarthedThree-Wire ... Read More

AC (Alternating Current) and DC (Direct Current) are the two different types of electric current that are used in the welding process. AC arc welding is commonly used for down-hand heavy plate welds, fast fills and with aluminium TIG welding with high frequency, while DC welding is better for welding thinner metals. Also, the equipment used for DC arc welding are also cheaper than AC arc welding machinery.The specifications of equipment used in practice for AC and DC arc welding are given as follows −Specifications of AC Arc Welding Machinery - AC transformer − Step down, oil cooled, 3-phase, 50 ... Read More

Resistance WeldingResistance welding is the process of joining of metals by applying mechanical pressure and by passing high electric current for a length of time through the metal area which is to be joined.The process of resistance welding was discovered by Professor Elihu Thompson in 1885 in Philadelphia. It was an accidental discovery, while experimenting with a spark coil operated form a bank of batteries, he accidentally welded two steel rods of about 0.635 diameter.The principle of resistance welding is the production of heat in the weld joint by passing a heavy current through the parts and this being followed ... Read More

In the infrared or radiant heating, the heating elements are of tungsten filament lamps operating at about 2400 °C. As at this high temperature a greater portion of infrared radiation is given to the object for heating. In this method of heating, the heating effect on the object is greater because the temperature of the heating element is greater.With the help of suitable reflectors, which are plated with rhodium, these infrared radiations are focused on the surface to be heated. The lamps used for the heating purposes in this method have ratings varying from 250 to 1000 watts operating at ... Read More

What is Electric Heating?The process in which electrical energy is converted into heat by resisting the free flow of electric current is known as electric heating.Whenever an electric current is made to pass through any circuit having a resistance of R ohms, then power dissipated in the circuit is equal to $\mathit{I^{\mathrm{2}}R}$ Watts. If the current flows for t seconds, then the electric energy consumed in the circuit is equal to $\mathit{I^{\mathrm{2}}Rt}$ Joules. This energy is converted into heat and worked out as $\mathit{I^{\mathrm{2}}Rt}/4.2$ Calories, where 4.2 is a constant called mechanical equivalent of heat.The use of heat produced by electricity ... Read More

Electric ArcAn electric arc is an electric discharge of gases which is produced by passing an electric current between two points called electrodes. The electric arc was first detected by British chemist Humphry Davy in 1808. The electric arc is the visible plasma between two electrodes due to the ionization of gases by the electric current. The electric arc is commonly used in welding, lighting and plasma cutting.Electrical Properties of Electric ArcThe electrical properties or characteristics of an electric arc are given below.Stability of Electric ArcThe electric arc has negative resistance characteristic, i.e. with the increase in the arc current, ... Read More