After the lamp has been lit for a long time, the operating voltage of the high pressure sodium lamp will gradually increase. When the operating voltage rises until the power supply voltage is insufficient to sustain the discharge, the sodium lamp will automatically extinguish; when the lamp cools down, the sodium vapor pressure in the discharge tube will drop and it will light up again.
The shell of the high-pressure sodium lamp is filled with inert gas. The leakage of the shell can cause oxidation of the metal cap, helium exhaust pipe and other components, resulting in a low temperature of the discharge tube, impeding the increase of the sodium vapor pressure in the tube and forming a large current. Cause the bulb to be damaged. To determine whether the shell is leaking, observe whether the black etch surface of the getter is present. If it has disappeared and a light white mark is left on the glass at the original evapotranspiration layer, the shell has leaked.
Many parts inside the bulb are connected by welding. The disconnection of the connection points or the burning of the nickel skin at the connection point due to vibration or current impact may cause the circuit to open and cause the sodium lamp to fail to light up.
Because the discharge of high-pressure sodium lamps has a declining volt-ampere characteristic, an inductance ballast must be used in series in the circuit to operate. However, for integrated fixtures such as ballasts and other accessories that are installed together with the light bulb, since the lamp temperature is high, the ballast Accessories and other accessories working environment is relatively harsh, it is easy to make the ballast insulation aging, resulting in ballast short circuit, short circuit, etc., so that the sodium lamp does not shine.