High Pressure Sodium Bulb
The High Pressure Sodium (HPS) lamp is a high-pressure version of a LPS lamp. The higher pressure makes the lamp less efficient but produces a more pleasing light. The arc tube material can't be made out of quartz because of the sodium (same reason as the LPS). It took around 30 years after the development of the LPS lamp to develop an arc tube to withstand sodium at high pressures.
The HPS lamps start up by using an ignitor and/or argon gas. Most HPS lamps need an ignitor to provide a starting voltage of 2.5kV or more. Special lamps are available that use the ballast peak/OCV voltage for starting (cutting costs and maintenance costs).
HPS has become really popular everywhere because it is very efficient (90-140 LPW) and has a more balanced spectrum than the LPS lamp. A standard HPS lamp produces a golden color light with a CRI around 20 and a color temperature 1900-2100K. Now HPS lamps are manufactured with a higher color temperature and an improved CRI. HPS lamps are manufactured in many shapes (R, T, ED, BT, DE). HPS bulbs are commonly available in 35-1000 watts.
High Pressure Sodium usage:
General lighting
Indoor lighting
Outdoor lighting
Road Lighting
Plant lighting
Outer bulb: Available in coated and clear versions.
Outer bulb nipple: Bulb seal with two leads.
Arc tube: Where light is generated. Contains mercury, sodium, and argon gas.
Main electrodes: The arc is generated between the two filament/leads.
Getter: (Ion Catcher) Collects ions from the bulb. Improving lamp performance.
Drawing and picture by: Paul Erik Hirvonen
