~Delete 28358

Sodium Vapour Lamp consists of a discharge tube made from a heat resistant glass, containing a little amount open site in new window of metallic sodium, neon gas and two electrodes, Neon gas is added to commence the discharge and to create adequate heat to vaporize the sodium. Simply because of law pressure inside the tube, a sufficiently extended tube needed to acquire more light. To reduce the overall dimension of the lamp, this tube is normally bent into U-shape.

The light produced by this lamp is yellowish which is created at its optimum pressure of about .004mm of mercury. This chicken coop with wheels pressure is obtained at a temperature of about 280 C and so it becomes essential to maintain this temperature. For this objective the U-tube is enclosed in a rent chicken koops double walled flask to avoid lose of heat. The double walled flask is interchangeable and can be fitted on to an additional U-tube. Although replacing the inner U-tube one particular need to be really cautious since if it is broken and sodium comes in speak to with moisture, it may result in fire.

All electric discharge lamps call for a higher voltage at the time of beginning and low voltage throughout operation. Typically, 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 commence the discharge. When the lamp is totally operative right after ten - 15 minutes, the voltage across it falls to about 150 volts. 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 really high (about 40 - 50 lumens/watt) and it produces a light of distinct wavelength getting yellow color. Sodium lamps are primarily employed for street, high way and airfield lighting exactly where color distinction is not so essential.