One type of gas-discharge lamps is metal halide lamps. They contain the same principle of luminescence that is used in every gas-discharge lamp. The principle is that in them an electric arc discharge occurs between the electrodes in the lamp, which is filled with mercury vapor and other chemical elements. The main difference from simple gas-discharge lamps will be that compounds such as metal iodides were included in the mercury vapor. These compounds are considered halogen. This ensures that evaporation from the electrodes of the tungsten lamp does not settle on the inner walls of the bulb.
During operation of a metal halide lamp, tungsten vapor interacts with halogen compounds, thereby forming a tungsten iodide mixture. And when the lamp is turned off, these particles return to the electrodes.
Therefore, lamp electrodes have high protection against destruction, and the bulb remains transparent for a long time. Plus, in these lamps, metal iodides are used to improve the quality of the light flux, since the spectral characteristics of the arc discharge change. Now this is the most economical and practical light source. Due to the addition of a tungsten-halogen cycle, the service life of the lamps has increased several times.
Where are they used?
MGLs produce brighter, higher quality light. They are used for general street lighting, site lighting, billboard lighting, and for lighting indoor industrial spaces. Due to their wide spectrum of luminescence, in some cases they are used for home lighting.
It can also be found in winter greenhouses and conservatories. This is due to the suitable light temperature for plant life.
MGL lamps are in particular demand among aquarium holders. Especially those who do this in large volumes for sale. This is due to the fact that metal halide aquarium lamps are able to reproduce the correct spectrum for fish life.
Design
In its structure, haze is not very different from mercury arc light sources. It also uses a burner made of ceramic or quartz. The flask plays a big role in ensuring the desired temperature, reduces heat loss and cuts off ultraviolet radiation. The flask is made of borosilicate glass, which has increased strength and heat resistance. You should know that industrial models do not provide an external flask; ozone-free quartz glass is used.
Due to the fact that modern modifications are used in the lamp, metal halide lamps do not contain incandescent filaments, which ensures longer service life. There is also easier starting due to the use of ignition electrodes.
Due to the fact that the flow of halides during the passage of the discharge depends on gravity, the lamp must be in the required position during operation. Lamps with two bases can only be operated in a horizontal position. Models with one base, for the most part, work when installed vertically. There are separate models that are suitable for work in any position. Horizontal models are marked with the letters “VN”, and vertical ones with “BUD”. For any position – “universal”.
MGL classification
Initially they are distributed into:
- Single-ended;
- Double-ended. Otherwise, double-base ones are called soffit;
- Without basement.
By type of base: 
- RX7s;
- G8.5;
This light source has 3 light spectrums:
- Warm spectrum, with a light temperature of 2700K;
- Neutral spectrum, with a light temperature of 4200K;
- Cold spectrum, with a light temperature of 6400K.
By marking:
- D – arc;
- P – mercury;
- Y – iodide.
By power.
- 220V – 20, 35, 50, 70, 150, 250, 400, 700, 1000 W;
- 380V – over 2000 W.
Types of luminaires may differ according to the type of installation:
- Recessed – when the lamp can be fixed in suspended ceiling structures;
- Overhead – when the device is attached to a wall or ceiling;
- Track - when the lamp has a special reflector that can accentuate the radius of the glow;
- Suspended - when the lamp can be suspended from the ceiling or ceiling lintels.
Advantages and disadvantages
As with all types of lamps, there are both advantages and disadvantages. The advantages include:
- The luminous flux of MGL is 4 times higher than that of incandescent lamps, and the efficiency is 8 times;
- Not picky about environmental conditions;
- Compact and energy saving;
- Service life about 15,000 hours;
- There is a wide choice of light temperatures.
The disadvantages include:
- Strong heating of the flask, which reduces fire safety;
- Sensitive to voltage changes;
- Requires time to reach full capacity;
- Cannot be turned on within 10 minutes after shutdown if there is no ballast;
- Sensitive to working position;
- Require special disposal.
MGL connection
Since this light source cannot be connected directly to the network, there are certain auxiliary devices that allow it to start. Since the burner cannot ignite itself, it needs a high-quality high-voltage discharge. For this purpose, a ballast control gear is provided, which is otherwise called ballast. They are electromagnetic and electronic. It is best to choose electronic ballasts, as they can significantly extend the service life and provide an even glow upon startup. Ballasts that have a built-in IZU have an advantage, which is capable of not only igniting the burner, but also limiting the current. Another advantage is their size, as they are more compact and lighter. To extend service life and save energy, it would not be superfluous to install a capacitor.
How to choose an MGL lamp
To select, you must first determine the required power. For small warehouses, 150-250W is enough; for stadiums, you need to use light sources of 1KW or higher. Next, you need to select the number of bases, while remembering that in a vertical position this light source shines a little worse and its service life will be shorter. Universal models fail faster and lose their light output earlier.
Some models require certain types of ballasts. For example, a European lamp may not work with an American ballast and vice versa. European products require ballasts with HQI marking.
Bottom line
Since there is little point in using MGL lighting for domestic purposes, you need to clearly understand its purpose, since these are rather industrial lamps. Due to the time that must pass before restarting, they should not be connected in areas with power outages. They may pose a fire hazard, so it is not recommended to use them near flammable objects. To run MGL lamps, you need to connect additional elements, which also need to be located in the lamp.
Video about MGL
Halogen lamps are a type of ordinary incandescent lamps, with one significant difference - while in ordinary lamps a high degree of vacuum is fundamental, then in halogen lamps a certain amount of gas is introduced - bromine or iodine vapor. What is the essence of this change? The operating principle of an incandescent lamp is to heat a tungsten filament with an electric current. During its service life, part of the metal from the surface of the spiral evaporates, which leads to a decrease in the thickness of the thread in some areas and, as a consequence, to an increase in the resistance of these areas. Increased resistance leads to increased temperature and, again, increased evaporation. This process is avalanche-like in nature, which ultimately leads to burnout of the spiral. In addition, the evaporated metal settles on the inner surface of the bulb, causing it to darken and reduce light transmission. The introduction of halogen vapor makes it possible to organize the so-called halogen cycle. It is based on the chemical reaction of the interaction of halogen vapors with evaporated metal. This compound is not stable and when exposed to high temperature of the coil, it decomposes into metal and halogen. The peculiarity of this reaction is that decomposition occurs near the most heated sections of the spiral, that is, where the thickness is smallest. The use of a halogen cycle can significantly increase the service life and increase the temperature of the coil, which leads to an increase in the quality of the luminous flux. Halogen lamps are smaller in size compared to incandescent lamps.
Features of operation.
The surface of the halogen lamp bulb has a high temperature and is made of special quartz glass. During operation, do not touch the surface of the glass with your hands. The slightest traces of fat burn at high temperatures, leaving blackening on the surface, which leads to local overheating of contaminated areas and failure of the halogen lamp. To prevent this, the glass flask must be washed with alcohol after installation, using a cloth that does not leave lint particles on the surface.
High temperatures also increase fire safety requirements.
Turning on halogen lamps together with a dimmer to adjust the brightness leads to a decrease in their temperature. This disrupts the halogen cycle and deposits metal on the inner surface. To avoid this, it is necessary to periodically turn on the lamp at full heat for several tens of minutes.
The high luminous efficiency and small dimensions of halogen lamps allow them to be successfully used in car headlights. 
Low voltage halogen lamps.
Lamps are available in different supply voltages. The use of low voltage lamps (usually 12 V) as lighting requires the use of step-down transformers. A transformer for halogen lamps can be made either traditionally, on a metal core (electromagnetic transformer), or using radio-electronic elements (electronic transformer). When meeting the maximum power requirements, electromagnetic transformers have very high reliability, but at the same time they have a high weight, which increases with increasing power. Electronic transformers are free from this drawback. However, if performed poorly, they can serve as strong sources of radio interference. In any case, the transformer for halogen lamps must have some power reserve.
Metal halide lamps.
Metal halide lamps have a completely different operating principle. In these lamps, the light source is an electrical discharge in a gas environment. Metal halide lamps (MHLs) are a further stage in the development of high-pressure gas-discharge lamps. They are known as DRL (mercury arc fluorescent). The basis of the operation of these lamps is an electric discharge in mercury vapor and inert gas. Since such a discharge produces mainly ultraviolet radiation, the inner surface of the bulb is coated with a layer of phosphor, which converts ultraviolet radiation into visible light. Using different coating compositions, you can obtain different shades of glow. 
The introduction of additives in the form of compounds of various metals with halogens makes it possible to change the color characteristics of MGL without using phosphors. Also, the introduction of halogen compounds makes it possible to almost completely get rid of such a drawback of DRL as difficulty igniting a lamp that has just been turned off, since the high pressure of heated mercury vapor does not allow a discharge to occur.
How the MGL is ignited can be seen in this video.
MGL design.
The main difference between most types of metal halide lamps and other types is the presence of two glass bulbs. The external bulb makes it possible to reduce the dependence on ambient temperature, which is important for the stability of the light parameters of the MGL.
Features of operation.
Since cold MGLs contain mercury, they are subject to specific requirements for their spatial location. MGLs are produced designed for installation in both vertical and horizontal positions.
Failure to comply with these requirements does not guarantee normal operation of the MGL. Lamps made with two bases are widely used in floodlights and allow only horizontal installation. Some types of MGL can be installed in different positions.
MGL connection.
The operating features of metal halide lamps require the use of specific equipment. The occurrence of an electrical discharge requires increased voltage and, at the same time, the physics of discharge in a gaseous environment have a greater dependence of the magnitude of the flowing current on the supply voltage, which forces the use of current-limiting elements. The starting and current limiting equipment is called starting and regulating equipment - ballasts. There are both transformer control gears, based on electromagnetic transformers with increased magnetic dispersion, and electronic ones. The latter have significantly smaller dimensions and weight. Electronic lamp control units must strictly correspond to the type of lamps used.
Information on IGL is well covered in the video:
Areas of use.
Increased light output, efficiency and small dimensions allow the use of metal halide lamps in various lighting equipment. The majority of lighting spotlights use MGLs.
The currently widespread car xenon headlights also belong to MHL. The presence of xenon serves mainly for the initial occurrence of the discharge. Further, during operation, the discharge occurs in mercury and halogen vapors.
MGLs are often incorrectly called metal halides. This name does not correspond to language norms. Also the name “metal halide” is a misnomer. This name is sometimes used as a result of reading the English name “metal halide lamp”.
Metal halide lamps (MHLs) are one of the types of high-pressure gas-discharge lamps (GRLs). The light bulb differs from other GRLs in that emitting additives (EAs) - metal halides - are dosed into the MGL burner to correct the spectral characteristics of the arc discharge in mercury vapor. Among light sources they are the most compact and powerful.
Metal halide lamps: what is important to know before buying?
Photo 1 - HPS lamp 70W/2000K 5800Lm E27 10t.h. (156x39) HPSL-70-E27-T IEC Use MGL:
- in construction;
- in architectural design;
- for illumination of greenhouses.
Types of metal halide lamps:
- single-base;
- double-ended;
- universal.
Photo 2 - Osram G12 70W In single-base cartridges, the cartridge is located on one side; double-base - double-sided, which allows it to be installed only in a horizontal position; The universal design can be installed both horizontally and vertically.
Most often, single-ended screw-type lamps are used, but double-ended lamps are considered more economical - their energy consumption is minimal.
Lamps are distinguished by burner type:
- quartz;
- ceramic.
IMPORTANT! Pay attention to the BLV MGL for the lines HITLITE, HIT-ULTRALITE, C-HILITE, TOPSPOT G12, TOPSPOT SHROUD, TOPSPOT G8.5, C-TOPSPOT, TOPLITE, TOPLITE SHROUD, TOPFLOOD.
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Lamps according to GOST must be designed so that their characteristics are reliable when used correctly.
Operating principle of MGL
Photo 3 - TDM DRI 70 6000 K Rx7s SQ0325-0012 The operating principle is based on the passage of an electric arc discharge in a gaseous environment, similar to that used in mercury lamps. The gas used in MGL is mercury and inert argon. The sodium and scandium iodides present in the gas ensure the passage of the arc discharge.
These substances do not react with the lamp bulb material (quartz glass). In the absence of a discharge, halides cover the walls of the product with a film. When the contact is closed, the temperature rises and an arc discharge is observed, which promotes the evaporation of halides and their decomposition into iodine and metal ions.
The glow of the lamp, visible to the eye, causes the presence of ions in the gas. In this case, the movement of ions from the hot zone of the lamp to the colder walls is observed - the connections are restored and condensation occurs on the walls in the form of a film. The lamp operates on a closed cycle principle.
Connecting light bulbs
Connecting the lamp to the network is carried out according to the rules, due to the design features and operating principle of the MGL. The peculiarity is that they depend on voltage, so the lamps require the inclusion of a current-limiting element (ballast) in a sequential order.
Most MGLs operate with serial ballasts designed for gas-discharge lamps (mercury or sodium arc lamps). There are ballasts with a built-in IZU with the functions of igniting the light source and limiting the current.
Photo 4 - MASTER CDM-T 70W/942 G12 PHILIPS 871150019927015 As the lamp warms up, the voltage and current in it fluctuate, so special requirements are placed on the design and quality of the current-limiting element. Poor quality causes low voltage and when turned on the lamp will begin to go out.
How to check?
Photo 4 - HQI-TS 150W/NDL EXCELLENCE RX7s-24 OSRAM 4008321678386 You can check the performance of the MGL in the usual way - turn on the lamp: if it lights intermittently, the lamp is faulty. You should check that the connection is correct, perhaps this is the reason.
If the lamps show unstable operation - they light up, go out, cannot flare up to the full expected power - you need to measure the voltage in the network. Metal halide lamps operate unstable at a voltage of 190 V.
Please pay attention to the correct connection in the power cable connector: the connection is correct if the voltage is normal and the phases correspond to the designations.
You also need to check:
- serviceability of the power cable (it may be broken);
- whether the power supply was inserted into the track correctly;
- correct connection to the panel.
If more than 20 lamps are mounted on a lighting structure consisting of several busbars, you should check whether they have enough power from the line supplying the structure. If the power is insufficient, unstable operation of metal halide lamps and ballasts (ballast control) is possible.
- Base G9
Suitable for small metal halide lamps and equipped with two pins spaced 9mm apart. The socket is a socket with holes at the same distance, so installing a light bulb in a lamp looks like a regular plug-socket connection.
IMPORTANT! The service life of some types of modern MGLs reaches 15,000 hours. They are produced with different radiation colors and color rendering quality.
Photo 5 - HQI-T 400W/N E40 OSRAM 4008321526786 To turn on the lamp, special ignition devices are required, since a voltage of several kilovolts is required to ignite the discharge. MGL, like all gas-discharge lamps, can only operate with a ballast choke, which creates a phase shift between current and voltage, therefore power factor compensation will be required, that is, the inclusion of a compensating capacitor.
The power supply current for 12 V lamps is quite large.
The radiation spectrum is of great importance, especially in greenhouses for growing seedlings and plants. The ability to correct the spectrum from warm white to yellow distinguishes them favorably from the xenon discharge with its cool white color.
Shelf life of MGL
Photo 6 - TDM DRI 250 6000 K E40 SQ0325-0016 Depends on:
- quality of quartz burners;
- processing quality;
- manufacturing company;
- storage conditions.
For example, Lisma lamps have a shorter shelf life under equal conditions than Osram or GE. As a rule, if storage conditions are met, MGLs are stored for decades, the main thing is that they do not leak.
Application of MGL
MGL, like sodium, is used in industry for lighting or landscape design. Gas-discharge MGL is often used on streets, squares and parks in night lighting devices, to illuminate monuments or buildings.
Photo 7 - It is an invariable attribute of stadium lighting, lighting design of circuses and arenas, office buildings and retail, advertising and other structures. Floodlight systems are the upper limit of power.
MGLs are not only plant-friendly, but also suitable for aquariums. A lamp with MGL provides high luminous flux and excellent color rendering throughout the entire operating period of the lamps.
MGLs are powerful lamps operating at high pressure and temperature. They are used with ballasts in special-purpose lamps. Typically, the MGL kit with built-in electronic ballasts includes a ballast starting device (required for arc lamps). Usually this is a large throttle and ignition device.
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Optimal conditions for metal halide lamps
When igniting the MGL, the conditions are very important, which directly affect the type of ballast used with a specific type of lamp. MGL require to adjust the value:
- ballast resistance current;
- supplying the correct voltage to the arc-creating electrodes.
For ballast-lamp systems, ANSI standards contain values for all required parameters for all components. A starter operating from an alternating current network is also important for the ignition device. It differs in straightening parameter and size. Ballast for electromagnetic type starters.
An ignition unit is required in any arc discharge lamp. There are two types for MGL:
- electronic ballasts (electronic);
- EmPRA (electromagnetic).
Short-lived and ineffective incandescent lamps are today being replaced by modern analogues with good light intensity and a wide power range.
Such representatives of the new generation of lighting technology are metahalogen lamps.
Thanks to its long service life and good color rendering, coupled with low heat dissipation and high light intensity, metal halide lamps have found their application in almost all spheres of human life, from illuminating plants to lighting shop windows and stadiums. The possibility of choosing a design also played a big role here - tubular with quartz or ceramic burners, double-ended bayonet or threaded, suitable for easy installation, single-ended with an internal or external bulb (the latter are most often used by photographers due to the almost perfect quality of light), with an aluminum reflector and simply compact - the features of a particular model depend on the required power and purpose of use.
Such lamps are turned on using a special one. Within two minutes, they reach maximum brightness of light emission, emitting a soft buzzing sound. However, it takes about five to ten minutes to relight them as they need to cool completely. This feature limits the use of metal halide lamps in some industries.
Usually, metal halide lamps cannot be used without indoor light due to their UV radiation. However, there are models with a built-in UV filter that are absolutely safe for humans.
Very durable, working up to 15,000 hours, with stable brightness throughout the entire period of operation, metal halide lamps will allow you to reduce costs for electricity, installation and technical support of any facility. Such bright and economical light sources cannot be purchased in regular stores, but on our website www.site you can choose the option that is right for you.
Due to its compactness, power and efficiency, they are considered a widespread light source in various lighting devices. metal halide lamps (MGL) . They are classified as gas discharge lamps (GRL) .
Specificity of MGL
The principle of glow of a metal halide lamp is the same as in other GRL is an electric arc discharge occurring between the electrodes in a flask filled with mercury vapor. The main distinguishing feature of metal halide lamps is the presence of radiating additives (certain metal halides) in the filler composition (mercury vapor).
Metal iodides are required to correct the spectral characteristics of the arc discharge; thanks to them, the quality of light radiation is much improved. They also prevent volatilized tungsten from settling on the inner walls of the flask. During operation of metal halide lamps, a reaction occurs between tungsten vapor and metal halides. As a result of this reaction, tungsten iodide (a gaseous mixture) is formed, which evaporates from the electrodes. After the lighting device is turned off, tungsten settles back onto the electrodes.
Installation of metal halide lamps
Metal halide lamps mainly consist of the following components:
- Discharge tube (torch) – which is the basis of the IGL. The burner is often made of quartz glass; there are also options made of special ceramics. Ceramic burners have higher heat resistance. The burner with electrodes is placed in the outer flask.
- Outer flask– performing the functions of a light filter. It is made from borosilicate glass. Borosilicate flasks have high thermal and mechanical resistance. The flask reduces heat loss from the burner, providing it with normal thermal conditions.
- Base.
It is impossible to launch an MGL without ballast; electromagnetic or electronic ones are used as it. The use of electronic ballasts ensures even light when lighting bulbs, significantly reducing currents (operating and starting), as well as increasing the service life of the lighting device.
Principle of operation
The luminous body of the MGL is the arc discharge plasma flowing in the torch between the electrodes.
The discharge tube is filled with inert gases and halogen compounds, which, when cold, condense on its walls in the form of a thin film. As the temperature of the arc discharge increases, the halides begin to evaporate and decompose into ions. After which the already ionized atoms are irritated and they create optical radiation.
The inert gas performs a buffer function, due to which the flow of electric current through the burner is possible even at its low temperature. As the burner warms up, mercury and emitting additives evaporate, thereby changing the emission spectrum, luminous flux and electrical resistance of the MGL.
To ionize the discharge, metal halide lamps require the use of special devices. Eg, And pulse ignition devices (IZU) ignition electrodes, such as in arc mercury phosphor lamps (MAL). And ignition occurs using ballasts. As such a device, you can use a choke or a transformer that has increased magnetic dissipation.
Classification and designations
Metal halide lamps are usually classified according to:
The base has a thread with which the light bulbs are screwed into the socket. These models are designated single-ended, with the letters SE;
- double-ended. Double-ended metal halides are called soffit; the outer bulb is usually made of quartz and has a small diameter. They operate in a horizontal position and are often used in floodlights for architectural and artistic lighting.
These lamps are inserted into sockets located on opposite sides of the lamp. They are designated double-ended, with the letters DE.
- Base type. Typically, single-base MGLs are produced with an E40 base, lamps with a ceramic burner come with an E27 base, and in low-power versions special bases G8.5, G12, etc. are installed.
Orientation of the position in which they work:
— horizontal. When operating these lamps, it is recommended to point the bulb nipple upward. Designation: BH;
- vertical. The lamps are designated by the letters BUD;
- universal. Lamps can work in different positions. But when they are used in a vertical position, they have a longer service life, as well as radiation intensity. Denoted by the letter U.Availability and shape of the flask:
- cylindrical(tubular Tubular = T);
- ellipsoidal. To reduce the glare effect, these lamps are made frosted (Ellipsoidal = “E”);
— ellipsoidal-tubular (Ellipsoidal Tubular = "ET");
— bulbous-tubular (bulbous tubular = BT);
- reflex(reflector = "R");
- parabolic(parabolic = "P");
- without flask. Bulbs without an outer bulb are manufactured to effectively utilize their ultraviolet radiation. These MGLs are prepared for use in technological processes.
Some MGLs are manufactured to replace DRL lamps. In such models, the inner walls of the outer flask are covered with a layer of phosphor.
Marking of MGL lamps
Domestic metal halides are marked with the letters DRI and DRISH, the letters are deciphered as follows:
- D – arc.
- R - mercury.
- AND - iodide
- Ш – spherical shape of the discharge tube.
After the letter value, the power of the light bulb is indicated, as well as the design. For example, DRI400 - 1 - arc mercury iodide lamps with a power of 400W, intended for filming.
Lamps with ceramic burners are marked with three letters CDM with numbers indicating the power; such light bulbs are produced only abroad. Various foreign manufacturers label lamps at their own discretion and do not adhere to uniformity.
Advantages and disadvantages
Advantages of MGL:
- High light output.
- Low power consumption.
- The service life is longer than that of incandescent lamps.
- Compactness.
- Reliable operation at low temperatures.
- Good color rendition.
Flaws:
- Lack of ability to regulate light output.
- Long time to warm up (working level is reached about 10 minutes after switching on).
- The need to use IZU.
- It is impossible to re-ignite the lamp immediately after turning it off until it has completely cooled down.
- They react to voltage surges (voltage changes of about 5% contribute to a change in the color of the light flux).
Despite the disadvantages, metal halide lamps are widely used in various lamps and lighting devices, this is due to their wide range of advantages.
Areas of use
- Film, studio and stage lighting.
- Architectural.
- Decorative.
- Utilitarian.
- Street lighting, namely for railway stations, quarries, sports facilities, etc.
Metal halide lamps are also used as light sources for car headlights and lighting installations in industrial buildings.
