For use in street lamps, factory floors, warehouses, economical, bright, small-sized luminaires are required. For these purposes, DRL lamps (arc mercury lamps) are often used, which create a luminous flux of significant power. The number in the lamp marking indicates its wattage. DRL 400 is a 400 W lamp.
Content
- Principle of operation
- Specifications
- Disadvantages of DRL lamps
Principle of operation
DRL lamps are a glass bulb with a phosphor coating applied to it. The flask is equipped with a threaded base. A discharge tube is mounted inside the flask (RT) or quartz burner, in which there are two electrodes - the main and additional, igniting. The flask is filled with argon, and a drop of mercury is added to the discharge tube.
More modern lamps have four electrodes, two main and two auxiliary, which eliminates the need for a special trigger. Only a choke (coil on a magnetic circuit) is needed. It is connected in series with the lamp and limits the current flow. This maintains the values required for the combustion of mercury vapor.
The mains voltage is supplied through the base to the electrodes located on both sides of the discharge tube. It is applied to the gap between the primary and secondary electrodes on each side.
The gap between the main electrodes of the discharge tube is also energized.
Under the action of the applied voltage between the main and additional electrodes, a glow discharge is formed, free electrons and positively charged particles appear in the bulb. When the amount of charges reaches the threshold values, an arc discharge occurs between the main electrodes. The lamp reaches its maximum burning characteristics after 7 minutes. This is due to the evaporation of mercury, which gradually intensifies the discharge between the main electrodes.
DRL lamps can be used in any position. But in the horizontal position, the arc in the discharge tube bends upward. The reason is the direction of convection flows when gases are heated. This reduces the power, luminous flux and service life of the device.
Specifications
When calculating lighting systems for indoor and outdoor spaces, it is necessary to take into account the technical characteristics of lighting devices. The common values of these parameters are as follows:
- Consume from 125 to 1000 watts.
- For lighting devices up to 250 W, an E27 base is used, for more powerful devices - E40.
- Luminous flux - from 5900 lumens to 59000 lumens.
- The period of operation is tens of thousands of hours.
- Possibility of operation at subzero temperatures.
The technical characteristics of the DRL 250 lamp (luminous flux 13500 lm) make it one of the most common lighting devices from this line.
This is a fairly powerful and economical device capable of creating a sufficient luminous flux for both outdoor conditions and industrial premises. The advantages of DRL luminaires are their low price., long service life and increased brightness.
Disadvantages of DRL lamps
In addition to significant advantages, mercury arc lighting devices have disadvantages. This determines their partial replacement with more modern LED lamps. The main disadvantages of DRL include:
-
The need for a stable source of mains voltage. The lamp does not light up or may go out when the voltage drops by 20%. - Special recycling technology due to the use of mercury and phosphor in these devices.
- Low color rendering. The world around us is somewhat distorted, which badly affects the mental state of people and causes fatigue of the retina.
- Reduced service life at temperatures below -20 ° C.
- Strong decrease in luminous flux after 2000 hours of operation.
- After turning off the device, it should take 10-15 minutes before turning it back on.
A negative feature of DRL luminaires is the fact that ozone is formed during combustion. To remove it in production areas ventilation should work well.
The base of the DRL lamps gets very hot during operation. Temperatures can reach 100 ° C. This must be taken into account when selecting cartridges and wiring for lighting fixtures.
Despite the drawbacks, mercury arc lamps are used in railway transport, in large industrial complexes, in street lighting, underground tunnels, and on construction sites. However, the course towards energy saving, perhaps, will force the switch to more economical LED luminaires in the coming years.
