HPS Construction and Operation

Marijuana Horticulture

by Jorge Cervantes

High pressure sodium lamps produce light by passing electricity through vaporized sodium and mercury within an arc tube. The HP sodium lamp is totally different from the metal halide in its physical, electrical, and color spectrum characteristics. An electronic starter works with the magnetic component of the ballast to supply a short, high voltage pulse.

This electrical pulse vaporizes the xenon gas and initiates the starting process that takes three to four minutes. Electricity passes, or arcs, between the two main electrodes. If the amp is turned off, r power surge occurs and the lamp goes out, the gases in the tube will usually need to cool three to fifteen minutes before restarting if possible.

Similar to the metal halide, the HP sodium has a two-bulb construction, with an outer protective bulb and inner arc tube. The outer bulb, or jacket, protects the arc tube from damage and contains a vacuum, reducing heat loss from the arc tube. The sodium, mercury, and xenon gas are contained within the arc tube and have a constant operating temperature. The lamp may be operated in any position (360 degrees). However, most prefer to hang the amp overhead in a horizontal operating position.