Metal Halide and Sodium Lamps and Fittings
METAL HALIDE LAMP
A metal halide lamp, as its name suggests, is an electrical lamp whose working involves a gaseous mixture of vaporised mercury and metal halides. The light is produced by an electric arc set up through this mixture. It is a high intensity discharge (HID) gas discharge lamp.
The primary visual in metal halide is that they emit white light. The passing of electrical currents through a mixture of mercury and metal halide gas gives the white colour. Metal halide lights are best used for commercial purposes like stadiums, parking lots and constructions. Its high intensity is best for long time use. In normal applications these lights are also used for vehicle headlights.
CONSTRUCTION OF METAL HALIDE LIGHTS
These metal halide lamps consist of a small fused quartz or ceramic arc tube containing the gases and the arc, which are encapsulated in a larger glass bulb.
This glass bulb has a coating that helps filter out the ultraviolet light produced inside. Some of these bulbs come with an additional phosphorus coating on the inner side of the quartz bulb. Phosphorus coating helps improve the spectrum and in the diffusion of light. They operate under an optimal pressure of 4 to 20 atmosphere and require a warm up period of a few minutes to reach its most effective output.
BEST USES OF METAL HALIDE LIGHTS
- They are used for extensive lighting purposes, both indoors and outdoors.
- They are used for commercial or industrial purposes such as factories, public spaces, parking lots, retail stores, etc.
- These lamps are used in automobile headlights.
- They are also used as photographic lighting and stage lighting.
HOW DOES A METAL HALIDE LAMP WORK?
- When the main electrodes experience full voltage, the arc is nil at the time of switching.
- Juxtaposed to the main electrodes are the auxiliary or starter electrodes that are attached to the glass stem. These starter electrodes create initial discharge between them.
- A bi-metal switch by the side shorts the starter electrode to the main electrode just when the lamp is starting.
- Starter electrode along with the main electrode create an initial arc heating up the metal halide salts.
- Primary discharge is in argon and then in mercury.
METAL HALIDE LAMP FITTINGS
Most of the metal halide lamps are fitted through an outer bulb to protect the inner elements and forestall loss of heat. Some outer bulbs are made of particularly doped “UV stop” fused silica blocking the UV light produced by the mercury vapour discharge partially or fully.
Edison screw metal bases are also used as a fitting solution for metal halide lamps. They differ in accordance with the power rating range (between 10 and 18,000 Watts). Double ended bases made of ceramic are also used.
A metal halide lamp may use an electrical ballast to hold it in place. These electrical ballasts are of two types:
- INDUCTIVE BALLAST: Also known as magnetic ballast, inductive ballast seems very similar to one used with fluorescent lamps. It has an iron core inductor that presents the impedance to AC current.
- ELECTRONIC BALLAST: Electronic ballast are lighter and more compact than inductive ballast. They consist of an electronic oscillator generating a high frequency current to operate the lamp.
A sodium vapour lamp is another kind of gas discharge lamp that makes use of sodium for producing light with a wavelength of upto 589 nanometres.
SODIUM (SON) LAMPS:
Sodium (SON) lamps, also known as “White” SON are high pressure sodium lamps with a colour temperature of 2700 Kelvin and colour rendering index (CRI) of around 85.
They resemble metal halide lamps in their construction.
Due to higher cost, low light efficiency and shorter service lives, Sodium (SON) lamps offer a very narrow category of usage, one being aesthetic effects.
They are used for aesthetic purposes in restaurants and indoor cafes and horticultural applications.
The lamp contains an amalgam of metallic sodium and mercury deposited at the coolest part of the lamp.
This amalgam provides the sodium and mercury vapour to create an arc.
With increasing temperature, and subsequently the vapour pressure, the terminal voltage increases.
With constant current, increasing voltage and energy, the lamp reaches its optimal level of operation.
SODIUM LAMP FITTINGS
Easy to install sodium lamps may be fitted with the following fittings:
- Screw in or plug in base fitting
Considering to buy Metal Halide & Sodium Lamps?
If you are deciding to buy metal halide and sodium lamps then look no further. The websites have a variety of collection of different electronic applications at a very reasonable price. You can get your choice of lamp fitting there. On their websites they have complete and detailed information about their products. So you can easily check out your desired product and read all the information mentioned. They also attach very clear images of the products for the better understanding of the customer.
If you order online then you can also check the ratings and reviews of the store and the products by the previous customers. They also have their offline store where they also have the same products at the same price.
If you want you can visit their store in person and see the products for yourself. Both online and offline options are available. But why go to the store when you have the ease of sitting at home and getting the products delivered at your desired location.
BRANDS TO LOOK FOR
There are many brands that sell metal halide and sodium lamps but these are some top notch brands that are said to have the top quality and top rated products in the market.