RamiresBissell726

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Sodium Vapour Lamp consists of a discharge tube produced from a heat resistant glass, containing a tiny amount of metallic sodium, neon gas and two electrodes, Neon gas is added to commence the discharge and to develop enough heat to vaporize the sodium. Simply because of law pressure inside the tube, a sufficiently extended tube necessary to acquire much more light. To minimize the overall dimension of the lamp, this tube is usually bent into U-shape. The light produced by this lamp is yellowish which is produced at its optimum pressure of about .004mm of mercury. This pressure is obtained at a temperature of about 280 C and so it becomes needed to maintain this temperature. For this objective the U-tube is enclosed in a double walled flask to stop lose of heat. The double walled flask is interchangeable and can be fitted on to one more U-tube. Whilst replacing the inner U-tube 1 must be really cautious because if it is broken and sodium comes in contact with moisture, it could result in fire. All electric discharge lamps require a larger voltage at the time of beginning and low voltage for the duration of operation. Generally, sodium vapour lamps are operated by a high leakage reactance transformer. At starting a high voltage of about 450 volts is applied across the lamp which is sufficient to start off the discharge. When the lamp is fully operative after 10 - 15 minutes, the voltage across it falls to about 150 volts. Simply because of the high reactance of circuit, the power element is low and therefore a p.f improvement capacitor is connected. The efficiency of a low pressure sodium vapour lamp is quite high (about 40 - 50 lumens/watt) and it produces a light of specific wavelength obtaining yellow color. Sodium lamps are mainly employed for street, high way and airfield lighting where color distinction is not so required. study backyard chicken coop