Mercury vapor lamps, recognizable by the bluish cast to their light output, would be the least efficient member of the Higher Intensity Discharge (HID) household. They were developed to overcome issues with fluorescent lamps for outdoor use and are truly much less effective than fluorescents. Current mercury lamp systems need to always be regarded as for retrofit with other higher efficiency alternatives, unless they operate quite few hours a year.The mercury vapor lamp produces light when the electrical current passes by means of a modest level of mercury vapor. The lamp consists of two glass envelopes: an inner envelope in which the arc is struck, and an outer protective envelope. The mercury vapor lamp, like the fluorescent lamp, demands a ballast designed for its specific use. Special ballasts are expected for dimming.

You can find two versions:
Low Stress:
The very first mercury vapor lamps had been in a reduce pressure tube. A single would tip the lamp, and electrical contacts on every side with the lamp would send electrical energy by way of a liquid mercury which began the lamp. Soon after that the lamp would heat speedy and mercury became a vapor. The light would intensify as the arc grew stronger within the tube.

Higher Pressure:
Lamps of now are higher pressure lamps with a fused quartz inner discharge tube. The higher stress aids boost efficiency and this was created in 1936, 35 years soon after the low stress lamps came out.This lamp begin having a little arc between the beginning electrode plus the principal electrode. This arc goes through argon gas which very easily strikes, even in cold climate. This tiny arc heats the tube, and more than various minutes the tube gets hot adequate to vaporize the strong mercury stuck to the sides. The mercury vaporized creates a sturdy light between the two key electrodes.

To stop the arc from infinitely getting stronger a ballast limits the present. Some lamps are “Self Ballasted”, they use an incandescent filament to act as a resistor, limiting present. Home lighting fixtures generally use the Mercury Vapor Ballast sorts exactly where because the much more expensive but extra efficient mercury Vapor Ballast lamps are located in massive fixtures for municipal lighting.

Applications:
The wattage at which a lamp operates will vary from its nominal rating based around the Mercury Vapor Ballast, the provide voltage plus the lamp voltage. When designing a Mercury Vapor installation, it’s essential to take these variables into account as the lumen output of your lamp varies with the wattage at which the lamp operates.