Sodium Vapour Lamp

出典: くみこみックス

Sodium Vapour Lamp consists of a discharge tube made from a heat resistant glass, containing a little amount of metallic sodium, neon gas and two electrodes, Neon gas is added to commence the discharge and to develop adequate heat to vaporize the sodium. Simply because compare chickencoop of law pressure inside the tube, a sufficiently extended tube essential to acquire far more light. To minimize the overall dimension of the lamp, this tube is generally 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 pressure the guide to chciken coops is obtained at a temperature of about 280 C and so it becomes needed to maintain this temperature. For this goal the U-tube is enclosed in a double walled flask to prevent shed of heat. The double walled flask is interchangeable and can be fitted on to yet another this page is not affiliated U-tube. Whilst replacing the inner U-tube one particular should be very careful because if it is broken and sodium comes in get in touch with with moisture, it might outcome in fire.

All electric discharge lamps call for a greater voltage at the time of beginning and low voltage in the course of operation. Generally, sodium vapour lamps are operated by a high leakage reactance transformer. At beginning a high voltage of about 450 volts is applied across the lamp which is enough to start off the discharge. When the lamp is fully operative following ten - 15 minutes, the voltage across it falls to about 150 volts. Because of the high reactance of circuit, the power issue is low and therefore a p.f improvement capacitor is connected.

The efficiency of a low pressure sodium vapour lamp is extremely high (about 40 - 50 lumens/watt) and it produces a light of specific wavelength possessing yellow color. Sodium lamps are mostly employed for street, high way and airfield lighting where color distinction is not so required.