HID Lighting
Starting and Restarting of HID lamps
HID lamps must be used where instant on is not required. All HID lamps have a warm up time to reach 90% light output. (Cold Start) Mercury vapor takes 5-7 minutes, low pressure sodium takes 7-10 minutes, high pressure sodium takes 3-5 minutes, metal halide takes 2-5 minutes.
If a power interruption of half cycle or more the arc in a HID lamp will extinguish. When power is restored immediate light output will not occur. The lamp will restrike and warm up. (Restrike) Mercury vapor takes 3-6 minutes, low pressure sodium takes 1-2 minutes*, high pressure sodium takes 1 minute*, metal halide takes 10-20 minutes*.
*LPS lamps may relight immediately if an ignitor is being used.
*HPS lamps may relight immediately if a special high power ignitor is being used.
HPS 1000 watt lamps take 2 minutes to reach 90% light output. HPS retrofit lamps take
3 minutes to reach 90% light output.
*MH lamps will restrike sooner if an ignitor is being used.
Operating HID lamps
Mercury Vapor lamps may be operated in open or enclosed fixtures. Most are rated universal burning position.
Low pressure sodium lamps should be operated in enclosed fixtures to prevent moisture and water contacting the bulb. All LPS lamps must be burned in a designed burning position. Most can be operated horizontal.
High pressure sodium lamps may be operated in open or enclosed fixtures. Most are rated universal burning position.
Metal halide and mercury vapor warning:
This lamp can cause serious skin burn and eye inflammation from short wave ultraviolet radiation if outer bulb is broken or punctured. Do not use where people remain more than a few minutes unless adequate shielding or other safety precautions are used.
Drawings and picture by: Paul Erik Hirvonen
