Products > High Pressure Sodium Lamps

What is a High Pressure Sodium (HPS) Lamp?

Invented in 1931, the high-pressure sodium lamp has a transparent discharge tube filled with a gas and sodium mixture (the conductor.) An electric current vaporizes the conductor causing it to glow, which results in the emission of light and heat.

A current regulating device, commonly known as the ballast, is required to limit and stabilize the current passing through the lamp, greatly reducing the loss of energy in the form of heat. The ballast also prevents overdriving of the lamp, resulting in longer lamp life.

What makes P.L. Light Systems HPS fixtures unique?

• P.L. Light Systems HPS fixtures are available in 150W, 250W, 400W, 400W Super, 600W, 750W, and the 1000W model with two new specially designed 1000W reflectors
• Available in 120, 208, 240, 277, 347, and 480 volts
• Improved collar design for easy assembly and maintenance of all reflectors
• Ventilated aluminum body allows for maximum cooling and increases dependability of internal components
• Compact body reduces the blockage of incoming natural sunlight
• C.S.A. and U.L. approved
• Optional convertible ballast - toggle switch provides the option of using either HPS or Metal Halide lamps in 400W/1000W

Each Fixture or Luminaire Consists of...

• A complete extruded aluminum enclosure housing a ballast kit, which includes a ballast, ignitor and a capacitor. The interlocking aluminum pieces are secured together by two punched aluminum plates. The endplate has an opening for the power supply cable to be inserted and secured. The front plate has the lamp mogul socket attached to it along with the specially designed reflector-mounting collar.
• One of seven styles of reflectors, including the new 1000 Watt Maxima, made of high quality, polished and anodized aluminum, secured to the mounting collar using its own unique adapter and locked into place.

Energy Efficiency

HPS is the most energy efficient lamp for greenhouse lighting. About 30% of the electric energy input is converted into PAR (the waveband between 400 -700 nm), compared to 6.7% for incandescent lamps. Only 14% of the light energy is in the waveband between 400 and 565 nm, and most of the rest in the region up to 700 nm, providing maximum plant growth. The rest is converted into heat energy.

The useful life of HPS lamps is twice that for Metal Halide (MH). The light output during the lamp life will drop less than 10%.

When To Use HPS Lamps

HPS lamps' result in excellent plant growth and development, provided the plants receive enough additional natural light. Due to the high surface temperature of the lamp (max. 450°C), the distance between the lamps and the plants should be sufficient to avoid crop damage.

HPS lamps are suitable for virtually all plant materials including vegetables, cut flowers, potted plants and bedding plants.