Sodium Vapour Lamp

出典: くみこみックス

Sodium Vapour Lamp consists of a discharge tube produced from a heat resistant glass, containing a modest amount of metallic sodium, neon gas and two electrodes, Neon gas is added to begin the discharge and to create adequate heat to vaporize the sodium. Due to the fact of law pressure inside the tube, a sufficiently extended tube essential to obtain far more light. To lessen the overall dimension of the lamp, this tube is normally bent into U-shape.

The light produced by this lamp is yellowish which is made 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 retain this temperature. For this purpose the U-tube is enclosed in a double walled flask to prevent lose of heat. The double walled flask is interchangeable and can be fitted on to yet another U-tube. While replacing the inner U-tube one particular need to be extremely cautious since if it is broken and sodium comes in contact with moisture, it could result in fire.

All electric discharge buy a chicken lamps need a larger voltage at the time of beginning and low voltage throughout 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 adequate to commence the discharge. When the lamp is completely operative right after ten - 15 minutes, the voltage across it falls to about 150 volts. Since of the high reactance of circuit, the chicken coop for sale power factor is low and hence a p.f improvement capacitor is connected.

The efficiency of a low pressure sodium vapour lamp is very high (about 40 - 50 lumens/watt) and it produces a light of specific wavelength having yellow color. Sodium lamps are primarily employed chicken coups info for street, high way and airfield lighting exactly where color distinction is not so essential.