Found 194 Articles for Power Systems

A gas discharge lamp that uses an electric arc through the vaporized mercury to produce light is known as mercury vapor lamp. The operation of the mercury vapor lamp is based on the excitation of atom of some gaseous medium. Also, the frequency and the wavelength of the radiation given out by different atoms of the gaseous medium depend upon the level of their excitation.Construction of Mercury Vapor LampThe construction and circuit for a mercury vapor lamp is shown in the figure below.It consists of an inner tube containing mercury vapor and it is made of hard glass.It also has ... Read More

A halogen lamp or tungsten halogen lamp is an incandescent lamp. The halogen lamp consists of a tungsten filament enclosed in an environment of an inert gas like argon and a small amount of a halogen like bromine or iodine. The combination of the tungsten filament and the halogen results in a chemical reaction (called regenerative cycle or halogen cycle).This regenerative cycle increases the life span of the filament. Also, the halogen cycle prevents the darkening of the lamp envelope by redepositing the tungsten from the inside of the lamp back onto the filament.Working Principle of Halogen LampThe working of ... Read More

A fluorescent lamp, also called fluorescent tube, is a low pressure mercury vapor gas-discharge lamp that works on the principle of fluorescence to emit visible light.When an electric current is passed through the fluorescent tube, it excites the mercury vapor which produces UV rays that then causes a phosphor coating on the inside of the lamp to glow.Construction of Fluorescent LampThe basic construction of a fluorescent tube lamp is shown in Figure-1.The fluorescent lamp is a low pressure mercury vapor lamp. Thus, due to low pressure, the lamp is made in the form of a long tube whose inside walls ... Read More

Different welding techniques are used for welding different metals or alloys, which are described below.Metal or AlloysWelding Methods & TechniquesDescriptionMild steels or Low carbon steelsForge weldingResistance weldingArc weldingGas weldingNo flux is required.Welding rods are made up of either mild steel or pure iron.No preheating of work is required.In order to minimize oxidation of steel in gas welding process, a neutral flame is used.Medium carbon steels (Carbon 0.3% – 0.5%)Arc weldingResistance weldingGas weldingThermit weldingPreheating required.The preheating temperature varies from 100 °C to 400 °C, depending upon the carbon content in the steel.A slightly carbonized flame used in gas welding process.High carbon ... Read More

Light is the electromagnetic radiation whose frequency is around 390 nm to 700 nm, and it is visible to the eyes of the human. Light is a form of energy which is produced from different source and these sources are termed as light sources.Types of Light SourcesThe sources of light can be broadly classified into following two categories, viz. −Natural Light SourcesArtificial Light SourcesNatural Light SourcesThe objects which are present in nature and have the ability to emit light of their own are known as natural light sources. In the universe, there are a lot of things that emit light ... Read More

The light received by any surface depends upon the distance of that surface from the source of light. The inverse square law gives the relation between the distance of the surface and the illumination of the surface.Statement of Inverse Square LawThe inverse square law states that "the illumination of a surface is inversely proportional to the square of distance of the surface from a point source of light."ExplanationLet us consider a point source of light 'S' having luminous intensity 'I' lumens per steradian. If two surfaces having areas A1 and A2 are placed at distances 'r' and 'R' meters away ... Read More

A fluorescent lamp or fluorescent tube is a low-pressure mercury vapor gas discharge lamp that uses fluorescence effect to produce visible light. In the fluorescent lamp, an electric current is passed through the gas which excites the mercury vapor to produce UV rays, these UV rays strike a phosphor coating on the inside of the lamp and causes it to glow.What is Stroboscopic Effect?The phenomenon which causes running or moving objects to appear stationary or appear to be operating slower than their actual speed, is known as stroboscopic effect.The stroboscopic effect produced by the fluorescent lamps is due to the ... Read More

Good Lighting SchemeA good lighting scheme is the one under the influence of which the eyes of a person do not feel any strain. For example, if the light is too dim, then we cannot observe the objects properly or cannot do reading or writing work. On the other hand, if the light is too bright, then our eyes start watering and are made to open forcibly. However, the good lighting does not have the above mentioned effects, but we find comfort while working under it.Requirements of Good Lighting SchemeIn order to make a lighting scheme good, the following factors ... Read More

IlluminationThe luminous flux received by the surface per unit area is known as illumination. It is denoted by the letter 'E' and is measured in Lux or Lumen/m2.Mathematically, the illumination is given by the expression, $$\mathrm{Illumination, \mathit{E}\: =\: \frac{Luminous \: Flux\left ( \phi \right )}{Area \left (\mathit{A} \right )}\: =\:\frac{\mathit{C\, P}\times \omega }{\mathit{A}}}$$Luminous IntensityLuminous intensity is defined as the amount of luminous flux emitted into a solid angle of a space in a specified direction. It is denoted by 'I' and is measured in Candela.Mathematically, $$\mathrm{Luminous\:Intensity, \mathit{I}\: =\: \frac{Luminous \: Flux}{Solid \: angle}}$$BrightnessThe luminous intensity per unit surface area of ... Read More

Projection welding is the resistance welding process which joins the metal pieces together by using the heat generated by an electric current. In this welding process, different projections are formed on the workpieces for effective welding, which is why the name "projection welding."Projection welding does not use electrodes for concentration of heat, instead the projection on the workpiece is used for this purpose. Actually, projection welding is a modified version of spot welding. It consists of forming slight projections on one of metal.Working of Projection WeldingThe schematic diagram of projection welding is shown in the figure.The set up used for ... Read More