At first glance, it seems that an LED lamp is an ordinary light source. For it to work, you just need to screw it into the socket and you're done. Actually this is not true. Such lamps have a complex structure and come in different types. For them to work smoothly, you need to know them specifications and use them to select a suitable model.

LED lamps are classified according to several criteria indicating their technical characteristics. In particular, this is its purpose, design and type of base. To have a better understanding of the varieties, let's look at each trait separately.

Purpose

Based on their purpose, LED lamps can be divided into the following types:

• for lighting residential buildings. Often used at home with base E27, E14;
• models used in designer lighting;
• for arranging outdoor lighting. This could be illumination of architectural buildings or landscape design elements;
• for illumination of an area in an explosive environment;
• street lighting models;
• a lot of LED lamps used in floodlights. They are used to illuminate industrial areas and buildings.

Design

Based on the type of design, LED lamps are divided into the following types:

• general purpose models are used for illumination of office and residential premises;
• LED lamp with directional light flow is installed in floodlights. They are used to highlight elements of architectural buildings and landscape lighting;
• Linear models are designed to replace fluorescent light sources. These LED lamps are made in the form of a tube and fit according to the type of base, which makes it possible to quickly replace one light source with another.

Base

LED lamps, depending on their purpose, have different types plinths. The main types found are:

1. Standard sockets with the letter "E" indicate the threaded type. The numbers indicate the diameter of the base, for example, E27. The threaded base of LED lamps is identical to the base of traditional filament light sources. This makes it easy to replace them at home in chandeliers, tabletop models, as well as in street lighting fixtures mounted on poles. In home use, lamps with a standard base, designated E27 or E14, are common. Another name for E14 is minion. Street lighting from poles requires the use of more powerful LED lamps. Big size The flask naturally has a larger base - E40.
2. The GU10 connector consists of 2 pins with thick ends. The design of the base is identical to the starter connectors used in older daylight sources (gas discharge). An LED lamp with such a base has a rotating mounting type in the socket. The letter designation of the connector indicates that G is a pin type, U is the presence of thickened ends. The number indicates the distance between the pins. IN in this case– this is 10 mm. The pin base is electrically safe and easy to install. The pin connector lamp is mainly designed for ceiling lamps with reflector.
3. The similar GU5.3 connector has the same pin type with a 5.3mm spacing. This type of connector for LED lamps was launched with an increase in demand for halogen light sources with the same connector installed in ceiling lighting fixtures. Models with this base are suitable for spot lighting installed in suspended ceilings. The base is easily inserted into the socket and is also electrically safe.
4. Linear tube-shaped LED products have a G13 base. This is the same pin type with 13mm spacing between elements. Such tubular models are used to replace fluorescent light sources. They are used to improve illumination of large areas, and are also installed in rooms with high, long ceilings.
5. The GX53 socket has a pin spacing of 53 mm. Lamps with this connector are used in overhead and recessed luminaires for furniture and ceilings.

Table of base types

Emitted light

The light that an LED lamp emits also refers to the classification of the product and indicates its technical characteristics.

Light flow

One of the important parameters that determines the technical characteristics of a light source is the luminous flux, that is, its emission power and efficiency. The unit of measurement for light flux is the lumen. The second parameter, efficiency, determines the ratio of the power of the first parameter to the power consumption of the light source Lm/W. In principle, this indicator reflects efficiency.

To compare the luminosity of LEDs with a conventional filament, one must take into account that a light source with a power of, for example, 40 W creates a luminous flux of about 400 Lm. There are tables for comparison luminous flux different light sources. From them you can find out that LED lamps have a luminous flux that is ten times more powerful than that of a conventional light source.

When buying a lamp for your home, you need to study the labeling. Conscientious manufacturers indicate luminous efficiency or luminous flux power. But most often found in labeling comparative characteristics LED light source in relation to its analogue with a filament. Especially such designations are most present on the packaging of Chinese products. In general, such marking can also be considered correct, although it is more of an advertising nature.

It should be summarized that over time, LEDs exhaust their service life, reducing the power of the luminous flux. This indicates their shortcomings, although nothing is eternal.

LED lamps differ from traditional filament light sources in their color rendering. The filament creates one warm color - yellow. LEDs are capable of emitting light over a wide range of colors, which is determined by the color temperature scale.

The color of hot metal is taken as the basis for constructing the scale. The unit of measurement is degrees Kelvin. For example, the yellow color of hot metal has a temperature of 2700 o K. The temperature of daylight ranges from 4500 to 6000 o K. Although white light at the lower limit has a yellowish tint. All colors with a temperature above 6500 o K belong to cold light with a blue tint. When choosing an LED light source for a room, you need to pay special attention to such characteristics. In addition to the fact that when a room is illuminated in different colors, the internal appearance of its decoration is shown, some shades can negatively affect a person’s vision. Eye fatigue highlights the shortcomings of LED lighting, but this can be easily corrected with the correct selection of color rendering.

Light distribution

If conventional light sources create maximum illumination of the space around them, then LEDs have a luminous flux direction in one direction. They emit light in front of them. This light distribution is suitable for a night light or other lighting device that requires a directed beam of light.

In order for the LEDs to produce uniform illumination of the space, they are equipped with a diffuser. Also, uniform distribution of light is achieved by installing LEDs on a plane at different angles. All these methods allow you to create a uniform distribution of light over a certain area. For example, LED lamps can have a luminous flux spread at an angle of 60 or 120 degrees.

Color rendition

There is a color rendering index, denoted Ra. The indicator is responsible for the natural color of an object falling into the illumination field of a certain light source. The index standard is sunlight, which is equal to an index of 100. LED lamps have an index of 80-90 Ra. For comparison, a regular incandescent lamp has a rating of at least 90 Ra. It is generally accepted that an index greater than 80 Ra is high.

Adjustable lamps

LED lamps, like filament light sources, can be dimmed. The lighting of the LEDs is controlled by a regulating device - a dimmer. This indicates the advantages of LED lamps, in contrast to their economical counterparts - fluorescent light sources. Using the regulator, you can achieve the room illumination that is most favorable for vision.

The regulator's job is to generate pulses. The brightness of the LED depends on their frequency. But not all LED lamps are dimmable. The adjustment can be limited by the LED driver built into the lamp, operating at a certain frequency. When choosing a light source for your home, you need to carefully read the technical specifications of the product, where the packaging will indicate whether the LED lamp is dimmable.

Power and operating voltage of lamps

When reading the technical specifications on the product packaging, many first of all pay attention to indicators such as power consumption and operating voltage. In other words, a person wants to know how much current the lamp needs for its normal operation and how much electricity it will consume.

The power consumption indicator plays an important role in calculating the total lighting consumption of a house or street. LED lamps produce different wattages, depending on their purpose. For example, for a home it will be enough to purchase products with a power of 3 to 20 W. To install street lighting, you will need more powerful lamps, for example, about 25 W. But the main thing is that it will not be possible to determine the brightness of the glow based on the power consumption.

Data for replacing incandescent lamps with LED lamps

Another important indicator is the operating voltage. The current source can be constant or variable. LEDs require a constant voltage of 12 V. A driver is responsible for their operation, which converts the network voltage to the required standards. With their help, LED lamps can operate on alternating current with a voltage of 220 V. There are models operating on direct and alternating current with a voltage of 12–24 V. These indicators must be taken into account when choosing lamps. Otherwise, a product with inappropriate performance when connected to the network will refuse to work or simply burn out.

LED lamp marking

If you take the packaging of any product, there is a marking on it that reflects all its technical data. It is similar to housekeeper labeling and includes the following parameters:

An LED light source that is correctly selected in all respects and that meets all the requirements of the manufacturer is guaranteed to last for many years. Now the main disadvantages of the products are only their high cost, but over time they will become available to all consumers.

The decline in retail prices for LED lamps has led to a sharp increase in their sales. However, the situation with choosing a quality product still remains a dead end for many. If it was easy to buy an incandescent light bulb, with the advent of CFLs the task has not become much more complicated due to the wider range and shades of emitted light. The parameters of LED lamps have significantly more points than those of previous generations of light bulbs.

But don't be afraid. To buy a good LED lamp, you don’t need in-depth knowledge of the product. It is enough to understand the basic parameters once, so that you can easily navigate among the numbers indicated on the packaging. So what does a buyer need to know about LED lamps, and what technical characteristics should they pay attention to before purchasing?

Main characteristics

Following the proverb: “You are greeted by your clothes...” it is enough to pick up a box with a light bulb to get acquainted with its main technical characteristics. You should pay attention not to the large bright numbers, but to the description printed in small print with 10 or more items.

Light flow

At a time when the incandescent lamp was the No. 1 light source, few people were interested in the concept of luminous flux. The brightness of the glow was determined by the rated power of the light bulb. With the advent of LEDs, the power consumption of light sources has decreased significantly, and the efficiency has increased. Due to this, savings appeared, which commercials so often remind us of.

Luminous flux (F, lm or lm) is a value that indicates the amount of light energy given off by a lighting device. Based on the luminous flux value, you can easily select a replacement for an existing bulb with a spiral. To do this, you can use the correspondence table below. Along with luminous flux, you can often come across the concept of “luminous efficiency”. It is defined as the ratio of luminous flux to power consumption and is measured in lm/W. This characteristic more fully reflects the efficiency of the radiation source. For example, a 10 W LED neutral light lamp emits a luminous flux of approximately 900-950 lm. This means that its light output will be 90-95 lm/W. This is approximately 7.5 times more than an analogue with a 75 W coil with the same luminous flux.

It happens that after replacing an incandescent lamp with an LED, its brightness turns out to be lower than declared. The first reason for this phenomenon is the installation of cheap Chinese LEDs. The second is reduced power consumption. Both of these reasons indicate a low quality product.

Also, the amount of luminous flux depends on the color temperature. In the case of LEDs, it is customary to indicate the luminous flux for neutral light (4500°K). The higher the color temperature, the greater the luminous flux and vice versa. The difference in light output between the same type of warm (2700°K) and cold (5300°K) LED lamps can reach 20%.

Power

Power consumption of an LED lamp (P, W) is the second most important technical characteristic, which shows how much electricity the LED lamp consumes in 1 hour. The total energy consumption consists of the power of the LEDs and the power of the driver. The most in demand nowadays are LED lighting devices with a power of 5-13 W, which corresponds to 40-100 watt filament lamps.

High-quality pulse-type drivers consume no more than 10% of the total power.

As advertising, manufacturers often use the concept of “Equivalent power”, which is expressed in the inscription on the packaging like 10 W = 75 W. This means that a 10 W LED lamp can be screwed in instead of a regular 75 W bulb without losing any brightness. A difference of 7-8 times can be trusted. But if there is an inscription on the box like 6 W = 60 W, then often this is nothing more than an advertising gimmick designed for the average buyer. This does not mean that the product is of poor quality, but the actual light output will most likely be the same as an incandescent lamp, not 60, but much less.

Supply voltage and frequency

The supply voltage (U, V) is usually indicated on the box as a range within which the manufacturer guarantees normal operation of the product. For example, parameter 176–264V indicates that the light bulb will confidently cope with any changes in mains voltage without a significant loss of brightness.

Typically, an LED lamp with a built-in current driver has a wide range of input voltages.

If the power source does not contain a high-quality stabilizer, then voltage drops in the power supply will greatly affect the light output and affect the quality of lighting. In Russia, the most common are LED lamps powered by 230V AC mains with a frequency of 50/60 Hz and 12V DC mains.

Base type

The size of the base must be known in order to select a light bulb in accordance with the existing socket in the lamp. The bulk of LED lamps are produced with threaded sockets E14 and E27, which are the standard for Soviet-style wall, table and ceiling lamps. It is not uncommon to see LED lamps with GU4, GU5.3 bases, which have replaced halogen lamps installed in spotlights and Chinese chandeliers with a remote control.

Colorful temperature

(TC, °K) indicates the hue of the emitted light. In relation to white LED lamps, the entire scale is conventionally divided into three parts: with warm, neutral and cold light. When choosing, you should take into account that warm tones (2700-3500°K) soothe and make you feel comfortable, while cold tones (from 5300°K) invigorate and excite the nervous system.
In this regard, it is recommended to use a warm glow for the home, and a neutral glow in the kitchen, bathroom and for work. LED luminaires with TC≥5300°K are only suitable for specific work and as emergency lighting.

Scattering angle

By the scattering angle one can judge the distribution of the light flux in space. This indicator depends on the design of the diffuser and the location of the LEDs. The norm for modern widely used lamps is a value of ≥210°. For efficient work with small parts, it is better to buy a lamp with a scattering angle of 120° and install it in a table lamp.

Dimmable

The ability to dim (control the brightness of lighting) of an LED lamp implies its correct operation from a dimmer switch. Dimmable lamps are more expensive because their electronic unit is more complex. A regular LED light bulb, when connected to a dimmer, will not work or will blink.

Ripple factor

(Kp) is not always listed in the list of characteristics, despite the fact that it is of paramount importance and has an impact on health. The need to measure this parameter arose due to the presence of an electronic unit in the lamp and the high response of LEDs. Low-quality power supplies are not able to perfectly smooth out the ripple of the output signal, as a result of which the LEDs begin to flicker at some frequency.

The ripple coefficient of LED lamps powered by a stable DC network is zero.

LED lamps with a coefficient below 20% are considered to be of the highest quality. In models with a current driver, the ripple factor does not exceed 1%. Define this parameter in practice it is not difficult using an oscilloscope. To do this, you need to measure the amplitude of the variable component of the signal on the LEDs and divide it by the voltage measured at the output of the power supply.

By the frequency of the alternating signal in the load, you can determine the type of driver used.

Operating temperature range

You should pay close attention to this characteristic if you intend to operate LED light bulb in non-standard conditions: on the street, in production workshops. Some models are able to work correctly only in a narrow temperature range.

Color rendering index

Using the color rendering index (CRI or Ra), you can evaluate how natural the color of objects illuminated by an LED lamp is. Ra≥70 is considered good.

Degree of protection against moisture and dust

This parameter is expressed as IPXX, where XX are two digits indicating the degree of protection against solid objects and water. It may not be found in the list of characteristics if the lamp is intended exclusively for indoor use.

Extra options

Product service life

Service life is a very abstract characteristic of an LED lamp. The fact is that by service life the manufacturer understands the total operating time of the LEDs, not the lamp. At the same time, the mean time between failures of the remaining parts of the circuit remains in great doubt. In addition, the operating time is affected by the quality of the housing assembly and soldering of radio elements. In addition, more than one manufacturer, due to its long service life, does not conduct full tests on the degradation of LEDs in the lamp. So the declared 30 thousand hours or more is a theoretical indicator, and not a real parameter.

Flask type

Despite the fact that the type of flask is not critical for many technical parameter, in many models it is indicated in the first line. Typically, the type and marking of the flask is expressed in a alphanumeric code.

Weight

Rarely is anyone interested in the weight of a product at the time of purchase, but for some lightweight lamps it matters.

Dimensions

How many manufacturers - so many different cases appearance and dimensions. For example, 10 W LED lamps from different manufacturers may differ in length and width by more than 1 cm. When choosing a new one led lamp for lighting, do not forget that it must fit into an existing lamp.

The market for LED products continues to develop dynamically, as a result of which the characteristics of lamps change and improve. We hope that in the near future quality standards will be developed for LED lamps that will make it easier for the buyer to make a choice. In the meantime, your own knowledge is the main support when choosing and purchasing.

Read also

In principle, fluorescent lamps are alternating current devices. However, they can also work on DC. The following factors must be taken into account:

• Operating on direct current, the lamp produces 75-80% of the light, in a mode similar to operating on alternating current.
• A resistor is used as a current limiter, which results in higher power losses.
• Lighting a lamp is usually more difficult. In most cases, a regular starter will not work.
• One end of the lamp may darken after several hours of operation. This is due to the movement of electrons to one electrode and positive mercury ions to the other. This leads to the fact that at one of the ends there is no generation of ultraviolet radiation necessary for phosphorus to glow. This can also lead to faster burnout of the electrodes. To eliminate this effect, you must regularly change the polarity of the supplied voltage.

Sometimes an inductor is connected in series to limit the starting current.

Using an incandescent lamp as a ballast

This option is sometimes used in circuits with a starter. The lamp filament is used as a current limiter. In principle, any resistor can be used as long as it allows the required power to be dissipated. The main disadvantages of using a lamp as ballast are:

• The efficiency of the circuit is very low because the incandescent lamp dissipates a lot of heat - it is a resistive load, unlike an inductance
• The fluorescent lamp does not operate in an optimal mode - light output, service life, etc. are reduced. The ballast is specially designed for a specific lamp, an incandescent lamp is unlikely.
• The heat generated (can reach up to 40-50 W) causes a decrease in the light output of the fluorescent lamp due to increased temperature.
• It is usually stated that an incandescent lamp provides additional light. However, when operating at full intensity, an incandescent lamp produces very little light in the visible range

We can say that you should not use such a scheme - it is better to purchase a special ballast.

However, there are some data that allow you to choose an incandescent lamp. A feature of incandescent lamps is that the resistance of the filament changes with increasing temperature. This table is calculated for the most common bi-spiral incandescent lamps with a bulb filled with an inert gas. The calculation was made as follows: first, a lamp was calculated, which at a rated voltage of 220V has the appropriate power and luminous flux, then the resistance of the spiral was recalculated to other current values.

Ballast for gas discharge lamp

A gas-discharge lamp - mercury or metal halide, similar to a fluorescent lamp, has a falling current-voltage characteristic. Therefore, it is necessary to use a ballast to limit the current in the network and ignite the lamp. Ballasts for these lamps are in many ways similar to ballasts for fluorescent lamps and will be described here very briefly.

The simplest ballast (reactor ballast) is an inductive choke connected in series with the lamp to limit the current. A capacitor is connected in parallel to improve the power factor. Such ballast can be easily calculated in a similar way to what was done above for a fluorescent lamp. It is necessary to take into account that the current of a gas-discharge lamp is several times higher than the current of a fluorescent lamp. Therefore, you cannot use a choke from a fluorescent lamp. Sometimes a pulse ignition device (IZU, inginitor) is used to ignite the lamp.

If the mains voltage is not enough to ignite the lamp, then the inductor can be combined with an autotransformer to increase the voltage.

This type of ballast has the disadvantage that when the network voltage changes, the luminous flux of the lamp changes, which depends on the power proportional to the square of the voltage.

rice. 2

This type (Fig. 3) of ballast with constant power (constant wattage) is now most widespread among inductive ballasts. A change in the mains voltage by 13% leads to a change in lamp power by 2%.

In this circuit, the capacitor plays the role of a current-limiting element. Therefore, the capacitor is usually installed quite large.

The best are electronic ballasts, which are similar to the electronic ballasts of fluorescent lamps. Everything that is said about those ballasts is true for gas-discharge lamps. In addition, in such ballasts you can regulate the lamp current, reducing the amount of light. Therefore, if you are going to use a discharge lamp to illuminate your aquarium, then it makes sense for you to purchase an electronic ballast.

rice. 3

Electronic ballasts

These ballasts come in both low-frequency and high-frequency types. Low-frequency ones feed the lamp from a frequent network, for example, hybrid ballasts (hybrid), which are a starterless ballast (rapid start), in which an electronic circuit is added that turns off the secondary circuit for heating the electrodes after the lamp is ignited, which gives a slight increase in the efficiency of the ballast. Aquariums

High-frequency electronic ballasts supply voltage to the lamp with a frequency of about 20,000 Hz and higher (they should not be confused with high-frequency induction lamps, which operate in the megahertz range). Such ballasts are a rectifier and a transient (or thyristor) chopper. Ballast has many advantages over magnetic ballast:

• The efficiency of the lamp increases. The ballast coefficient increases by 20-30%, i.e. lamp produces more light
• Losses in ballast have been reduced several times - a huge piece of iron is missing. Accordingly, energy consumption decreases and the temperature decreases, which is important for the operation of the lamp.
• The ballast becomes compact, which is important when placing it in a tight place.
• The ballast does not produce noise in the audio range.
• Lamp pulsations are reduced
• Many ballasts allow the possibility of changing the luminous flux of the lamp (dimming)

Electronic ballast also has its disadvantages:

• Relatively high cost compared to magnetic ones.
• Some older ballast designs had a small amount of current leaking into the ground wire, causing the GFCI system to trip.
• These ballasts (especially cheap ones) may have increased harmonic distortion. They can affect a radio receiver working nearby (although unlikely - within a radius of no more than half a meter)

However, when purchasing new system lamps, especially HO, VHO lamps, it makes sense to think about using electronic ballast

The figure shows the increase in lamp efficiency with increasing current frequency, relative to the mains frequency of 60Hz

Wiring diagram for a fluorescent lamp without a starter

Disadvantages of the starter circuit ( for a long time heating of the electrodes, the need to replace the starter, etc.) led to the appearance of another scheme, where the heating of the electrodes is carried out from the secondary winding of the transformer, which is also an inductive reactance.

A distinctive external feature of such a ballast is that both network wires are connected to the ballast, four wires from the ballast are connected to the lamp electrodes.

There are many varieties of such a circuit, for example, when an electronic circuit turns off the electrode heating circuit after turning on the lamp (trigger start), etc. Ballasts of this type are also used in a circuit with several lamps.

You cannot use a lamp designed for a starter switching circuit in such a circuit, since it is designed for longer heating of the electrodes and will fail prematurely in such a circuit. Only lamps marked RS (Rapid start) should be used. The circuit must provide a grounded reflector along the lamp (sometimes there is a metal strip on the lamp). This makes lighting the lamp easier.

The figure shows the internal view of such a ballast. It consists of a choke (core and coil), a capacitor for power factor correction (power capacitor) and a thermal fuse (thermal protector). Everything inside the case is filled with thermal dissipative material

Wiring diagram for a fluorescent lamp with a starter

A traditional circuit, used for a very long time, in the case when the mains voltage is sufficient to light the lamp. It uses a ballast, which is a large inductive reactance - a choke, and a starter - a small neon lamp that serves to preheat the lamp electrodes. There is a capacitor in the starter parallel to the neon lamp to reduce radio interference. A capacitor can also be included in the circuit to improve the power factor.

When you turn on the lamp in the network, first, a discharge occurs in the starter and a small current passes through the electrodes of the lamp, which heats them, thereby reducing the ignition voltage of the lamp. When a discharge occurs in the lamp, the voltage between the electrodes drops. disconnecting the starter circuit. In old schemes, instead of a starter, a button was used, which had to be held for several seconds.

The ballast is used only to limit the current. It’s easy to calculate the ballast parameters yourself (if you found a choke in the trash and want to use it).

The parameters of an inductive ballast can be determined very easily using the rules for calculating AC circuits. For example, consider a 40W lamp (F40T12) 48" (122 cm) long, connected to a 230V network

The operating current of the lamp is about 0.43A. The power factor of the lamp is approximately 0.9 (in principle, the lamp can be considered an active load). The voltage on the lamp is: 40W/(0.43A*0.9)=102V. The active component of the voltage is equal to: 102V*0.9=92V, the reactive component is equal to 102V*sqrt(1-0.9^2)=44V.

Power losses in ballast are 9-10W. Hence, the total power factor is equal to: (40W+10W)/(230V*0.43A)=0.51 (this clearly requires a correction capacitor). The active component of the voltage drop across the ballast is equal to: 230V*0.51-102V=15V, the reactive component 230V*sqrt(1-0.51^2)-44V=154V. The active resistance of the ballast is 15V/0.43A=35 Ohm, the reactive resistance is 154V/0.43=358 Ohm. The ballast inductance at a frequency of 50Hz is 358/(2*31.4*50)=1.1H

A similar calculation for a 30W lamp (F30T12) 36" (91 cm) long, with an operating current of 0.37A, gives the ballast parameters - active resistance is 59 Ohms, reactive 450 Ohms. The total power factor is 0.45. Ballast inductance is 1.4H

From here, it is generally clear what will happen if you use a ballast for a 40W lamp in a circuit with a 30W lamp - the current will exceed the rated value, which will lead to faster failure of the lamp. Conversely, using ballast from a less powerful lamp in a circuit with a more powerful lamp will result in current limitation and reduced light output.

A capacitor can be used to improve the power factor. For example, in the first example, for a 40W lamp, a capacitor connected in parallel is calculated as follows. The current through the capacitor is 0.43A*sqrt(1-0.51^2)=0.37A, the reactance of the capacitor is 230V/0.37A=622Ohm, the capacitance for a 50Hz network is: 1/(2*3.14*50*622)=5.1uF. The capacitor must be 250V. It can also be connected in series (calculated similarly), but you must use a 450V capacitor. Aquarium

CONTENT

Introduction

1. 
   Classification and main parameters of electric light sources
   1. 
      Incandescent lamps
   2. 
      Low pressure fluorescent lamps
   3. 
      High pressure fluorescent lamps
2. 
   Power supply circuits for fluorescent lamps
3. 
   Basic lighting quantities
4. 
   Safety precautions when servicing electric lighting installations

INTRODUCTION

Electric lighting installations are used in all industrial and domestic premises, public, residential and other buildings, on streets, squares, roads, crossings, etc. This is the most common type of electrical installation. There are three types of electric lighting.

Work lighting Intended for normal activities in all indoor and outdoor areas with insufficient natural light. It should provide normal illumination in the workplace.

Emergency lighting is intended to create conditions for the safe evacuation of people in the event of an emergency shutdown of working lighting in premises or the continuation of work in areas where work cannot be stopped due to technology conditions. Emergency lighting must create an illumination of at least 5% of the total to continue work or at least 2 lux, and evacuation lighting - at least 0.5 lux on the floor, along the main passages and stairs.

Security lighting along the borders of the protected area is an integral part of working lighting, will create illumination of the area on both sides of the fence.

According to the rules for electrical installations, lighting is divided into three systems.

General lighting in industrial premises it can be uniform (with uniform illumination throughout the room) or localized when lamps are placed so that increased illumination is created at the main workplaces. The local system provides illumination of workplaces, objects and surfaces.

Combined is a lighting system in which local lighting is added to the general lighting of a room or Space, creating increased illumination in the workplace. The main element of a lighting electrical installation is a light source - a lamp that converts electricity into light radiation.

Two classes of light sources are widely used: incandescent lamps And gas-discharge(luminescent, mercury, sodium and xenon).

The main characteristics of the lamp are the nominal voltage values, luminous flux power (sometimes luminous intensity), service life, as well as dimensions (total length L , diameter, height of the light center from the central contact of the threaded or pin base to the center of the thread).

The most common types of bases: E- threaded; INs - pin single-contact, Vd - pin two-pin(subsequent letters indicate the diameter of the thread or base).

In addition, focusing R, smooth cylindrical soffit SV some other bases.

In the marking of general purpose lamps, the letters mean: V - vacuum, G - gas-filled, B - double-spiral gas-filled, BK - double-spiral krypton.

Of great importance is the dependence of the characteristics of incandescent lamps (IL) on the actual voltage supplied. As the voltage increases, the temperature of the filament increases, the light becomes whiter, the flux increases rapidly and the luminous efficiency is somewhat slower, as a result of which the service life of the lamp sharply decreases.

Low-pressure tubular fluorescent mercury lamps (LMs), widely used in lighting installations, have a number of significant advantages compared to LNs; for example, high luminous efficiency reaching 75 lm/W; long service life, reaching up to 10,000 hours for standard lamps: the ability to use a light source of different spectral composition with better color rendering for most types than incandescent lamps; relatively low (albeit creating glare) brightness, which in some cases is an advantage.

The main disadvantages of LL lamps are: the relative complexity of the switching circuit; limited unit power and large dimensions of the assigned power; impossibility of switching lamps operating on alternating current to power from a direct current network: dependence of the characteristics on the ambient temperature. For conventional lamps, the optimal ambient temperature is 18 - 25°C; if the temperature deviates from the optimal temperature, the luminous flux and luminous efficiency are reduced; at t
Under current standards, in which the gap between the illuminance values ​​for incandescent and gas-discharge lamps in most cases does not exceed two steps, the high luminous efficiency and long service life of LLs, as well as DRL lamps, make them in most cases more economical than incandescent lamps.

The advantages of DRL lamps are: high luminous efficiency (up to 55 lm/W); long service life (10,000 hours); compactness; resistance to environmental conditions (except for very low temperatures).

The disadvantages of DRL lamps should be considered: the predominance of the blue-green part in the spectrum of rays, leading to unsatisfactory color rendering, which precludes the use of lamps in cases where the objects of discrimination are human faces or painted surfaces; ability to operate only on alternating current; the need to switch on through a ballast choke; the duration of flare-up when turned on (about 7 minutes) and the beginning of re-ignition even after a very short interruption in power supply to the lamp after cooling (about 10 minutes); pulsations of the light flux, greater than that of fluorescent lamps; significant reduction in luminous flux towards the end of its service life.

Incandescent lamps are manufactured for voltages of 12-20 V with a power of 15-1500 W. The service life of general-purpose incandescent lamps is 1000 hours. The luminous flux, measured in lumens, per 1 W of power consumed by the lamp ranges from 7 (for low-power lamps) to 20 lm/W (for high-power lamps). The bulbs of incandescent lamps are filled with neutral gas (nitrogen, argon, krypton), which increases the service life of the tungsten filament and increases the efficiency of the lamps.

Currently, incandescent mirror lamps of the ZK and ZSh types are produced for higher voltages: 220-230, 235-245 V.

Halogen incandescent lamps of the KG-240 type (tubular in shape with a tungsten filament in a quartz bulb) with a power of 1000, 1500 and 2000 W have become widespread due to their increased light output.

Fluorescent lamps are a glass tube filled with gas - argon, the inner surface of which is coated with a phosphor. There is also a drop of mercury in the tube. When connected to the electrical network, mercury vapor is formed in the lamp and light appears close to daylight.

The electrical industry produces a series of energy-efficient LL lamps designed for general and local lighting of industrial, public and administrative premises (LB18-1, LB36, LDTs18, LB58). For residential premises, lamps LETS18, LETS36, LETS58 are used, which, compared to standard LLs with a power of 20, 40, and 65 W, have increased efficiency, reduced electricity consumption by 7-8%, lower material consumption, and increased reliability during storage and transportation. For administrative premises, LLs with improved color rendering (LEC and LTBTS) with a power of 8-40 W are produced. The lamps have linear and shaped shapes (U and W-shaped, ring-shaped). All lamps, except ring lamps, have two-pin sockets at the ends.

According to the spectrum of emitted light, LLs are divided into types: LB - white, LCB - cold white, LTB - warm white, LD-daylight and LDC - daytime with correct color rendering.

Color-corrected high-pressure DRL mercury arc lamps consist of a glass bulb coated with a phosphor, inside of which a quartz gas-discharge tube filled with mercury vapor is placed.

DRI gas-discharge metal halide lamps are produced with a luminous efficiency of 75-100 lm/W and a burning duration of 2000-5000 hours. These lamps provide better color rendition than DRL lamps.

To illuminate dry, dusty, and damp rooms, metal halide mirror lamps of the DRIZ type are produced.

400 and 700 W HPS sodium lamps emit golden-white light; their luminous efficiency is 90-120 lm/W, burning duration is more than 2500 hours.

1. 
   Classification and main parameters of electric light sources

Electric light sources can be divided into temperature(incandescent lamps) and luminescent(fluorescent and gas-discharge lamps).

Basic parameters of electric light sources: supply voltage; rated power; luminous efficiency, measured by the number of lumens per watt (lm/W); starting and operating currents; nominal luminous flux; decline in luminous flux after a certain period of operation; average lamp operating time.

1.1. Incandescent lamps

Electric incandescent lamps are still widely used for lighting purposes, due to their ease of operation and connection to the network, reliability and compactness.

The main disadvantage of incandescent lamps is their low efficiency (about 2%), i.e. incandescent lamps provide more heat than light. The service life of incandescent lamps is on average 1000 hours. Incandescent lamps are very sensitive to changes in the voltage supplied to them. Increase voltage by 1 % in excess of the nominal leads to an increase in luminous flux by 4% and a decrease in service life by 13-14 %. When the voltage decreases, the service life increases, but the luminous flux of the lamp decreases, which affects the productivity of workers.

The service life of incandescent lamps is reduced by vibration, frequent switching on and off, and non-vertical position. The light of incandescent lamps differs from natural light by the predominance of rays of the yellow-red part of the spectrum, which distorts the natural colors of objects.

Incandescent lamps can be vacuum(type B with power from 15 to 25 W) and gas-filled(types G, B, BK with power from 40 to 1500 W).

Gas-filled lamps of type G (monospiral) and B (bispiral) are filled with argon with the addition of 12-16% nitrogen.

Structurally, a bispiral lamp differs from a monospiral lamp in that its filaments have the shape of double spirals, i.e., a spiral twisted from a spiral. These lamps have a luminous efficiency that is approximately 10% higher than that of conventional (monospiral) lamps.

Bispiral lamps with krypton filling (BK type lamps) are externally distinguished by their mushroom-shaped shape and have a luminous efficiency 10-20% higher than lamps with argon filling. Due to the high cost of krypton gas, BK type lamps are produced with a power of 40 to 100 W.

Note that the tungsten filament can be folded not only into a spiral and bi-spiral, but also into a tri-spiral and form various structural shapes (cylindrical, ring, rectangular, etc.). Scale of rated power of general purpose incandescent lamps (W): 15, 25, 40, 60, 75, 100, 150, 200, 300, 500, 750, 1000.

Lamps with a power of 15 and 25 W are produced vacuum, 40-100 W - bispiral with argon or krypton filler, 150 W - monospiral or bispiral and 200 W and above - monospiral with argon filler. Luminous output of lamps is 7-18 lm/W.

For lamps with a power from 15 to 200 W, an E27/27 base is used, for lamps with a power of 300 W with a bulb 184 mm long - an E27/30 base, for lamps with a power from 300 to 1000 W - an E40/45 base.

Lamps with a power of up to 300 W can be manufactured in both transparent and frosted (MT), opal (O), milk (ML) flasks. Note that opal is a mineral of the hydroxide subclass (SiO 2 x nH 2 O).

Conventional designations for general purpose incandescent lamps: the word “lamp”, type of filling and filament body, type of lamp bulb (if it is opaque), voltage range, rated power, GOST number. For example, the designation “Lamp B 125-135-25 GOST 2239-79” is deciphered as follows: vacuum lamp, transparent bulb for voltage 125-135 V, power 25 W, manufactured according to GOST 2239-79.

The designation “Lamp GMT 220-230-150 GOST 2239-79” reads as follows: gas-filled monospiral argon lamp in a frosted flask for a voltage of 220-230 V, power 150 W, manufactured in accordance with GOST 2239-79.

Incandescent lamps for local lighting are manufactured for a voltage of 12 V with a power of 15 to 60 W and for a voltage of 24 and 36 V with a power of 25, 40, 60 and 100 W. The designation of these lamps, for example MO-36-60 or MO-12-40, is deciphered as follows: an incandescent lamp for local lighting with a voltage of 36 V with a power of 60 W and an incandescent lamp for local lighting with a voltage of 12 V with a power of 40 W. In addition, miniature incandescent lamps of type MH with a voltage of 1.25 V and a power of 0.313 W are produced; 2.3 V power 3.22 W; 2.5 V power 0.725 W, 1.35 W, 2.8 W; 36 V power 5.4 W. The luminous flux of lamps may decrease over time. There are standards for reducing the luminous flux of each lamp after 750 hours of operation at the design voltage.

IN Lately Incandescent lamps, the bulbs of which are covered with a mirror or white diffuse reflective layer, are widely used. Such lamps are called luminaire lamps. The mirror part of the bulb is given the appropriate shape in order to obtain a certain luminous intensity curve (Fig. 2.2). Since lamps with reflective coatings have the necessary luminous intensity curve, lighting devices without optical devices are used for their use, which significantly reduces the cost of lamps for them. These lamps do not require cleaning, and their luminous flux is more stable during operation.

Incandescent lamps with reflective layers (lamp-luminaires) are divided into: general lighting lamps with a diffuse (D) layer of the NGD type (incandescent lamps, gas-filled with argon, monospiral with a diffuse layer); local lighting lamps with a diffuse layer of the MOD type; mirror lamps with medium (G) light distribution, type NZS; mirror lamps with wide (W) light distribution, type ZN27-ZN28; mirror lamps with concentrated light distribution, type NZK; mirror lamps for local lighting type MOZ.

General lighting lamps with a diffuse layer of the NGD type are manufactured for a voltage of 127 V with a power of 20, 60, 100, 150 and 200 W and for a voltage of 220 V with a power of 40, 100, 150, 200 and 300 W.

Local lighting lamps with a diffuse layer of the MOD type are manufactured for a voltage of 12 V with a power of 25, 40 and 60 W and for a voltage of 36 V with a power of 40, 60 and 100 W.

Mirror lamps with a medium (G) light distributor of the NZS type are available for voltages of 127 and 220 V with a power of 40, 60, 75 and 100 W.

Mirror lamps with a wide (W) light distribution of type ZN30 are produced only for a voltage of 220 V with a power of 300, 500, 750 and 1000 W.

Mirror lamps with concentrated light distribution of the NZK type are available for voltages of 127 and 220 V with a power of 40, 60, 75, 100, 150, 200, 300, 500, 750 and 1000 W. The service life of all lamps with a voltage of 220 V and lamps with a power from 150 to 1000 W at a voltage of 127 V is 1500 hours.

Mirror lamps for local lighting of the MOZ type are available only at a voltage of 36 V with a power of 40, 60 and 100 W.

The service life of all lamps not noted above is 1000 hours. The luminous efficiency of the lamps is 8.5-20.6 lm/W.

The industry also produces halogen incandescent lamps, the service life of which is 2000 hours or more, i.e. 2 times more than the above lamps.

Iodine is added to the gas filling of the bulb of a halogen incandescent lamp, which, under certain conditions, ensures the reverse transfer of evaporated tungsten particles from the walls of the lamp bulb to the filament body. It is this circumstance that makes it possible to double the service life of an incandescent lamp with increased luminous efficiency. Halogen lamps have linear and compact filament bodies. Linear filament bodies are made in the form of a long spiral (the ratio of the length of the spiral to the diameter is more than 10), which fits into a tubular quartz flask with end inputs. Compact filament bodies have a shorter spiral length. These lamps also have a smaller bulb.

Designation of halogen lamps: KG220-1000-5 - halogen lamp with a quartz glass bulb, iodine, voltage 220 V, power 1000 W, development number 5; KGM (small-sized) for voltages of 30, 27 and 6 V.

Tubular halogen incandescent lamps are available for a voltage of 220 V with a power of 1000, 1500, 2000, 5000 and 10,000 W, as well as for a voltage of 380 V with a power of 20,000 W. The luminous flux of halogen lamps ranges from 22 klm (1000 W lamps) to 260 klm (10,000 W lamps). The luminous efficiency of these lamps is 22-26 lm/W.

Due to the instability of the supply voltage, incandescent lamps are currently produced that allow a voltage deviation in the range of ±5 V from the calculated one. The voltage range is indicated on the lamp, for example 125-135 V, 215-225 V, 220-230 V, 225-235 V, 230-240 V.

For increased voltage of the electrical network, special incandescent lamps are produced for a rated voltage of 235 V and 240 V. Here the voltage range is 230-240 V and 235-245 V. The rated voltage of 240 V is used only for lamps with a power of 60, 100 and 150 W. Lamps for voltages of 235 and 240 V should not be used with a stable voltage of 230 V due to a sharp decrease in their luminous flux in such a network.

1.2. Low pressure fluorescent lamps

Low-pressure fluorescent tubular lamps are a glass tube sealed at both ends, the inner surface of which is coated with a thin layer of phosphor. The lamp is evacuated and filled with the inert gas argon at very low pressure. A drop of mercury is placed in the lamp, which when heated turns into mercury vapor.

The tungsten electrodes of the lamp have the form of a small spiral coated with a special composition (oxide) containing carbon dioxide salts of barium and strontium. Two hard nickel electrodes are located parallel to the spiral, each of which is connected to one end of the spiral.

In low-pressure fluorescent lamps, a plasma consisting of ionized metal and gas vapor emits in both the visible and ultraviolet parts of the spectrum. With the help of phosphors, ultraviolet rays are converted into radiation visible to the eye.

Low-pressure fluorescent tubular lamps with an arc discharge in mercury vapor are divided according to the color of the radiation into white light lamps (LB type), warm white light lamps (LTL), and color corrected daylight lamps (LDC).

Scale of rated powers of fluorescent lamps (W): 15, 20, 30, 40, 65, 80.

The design features of the lamp are indicated by letters following the letters indicating the color of the lamp (P - reflector, U - U-shaped, K - ring, B - quick start, A - amalgam).

Currently, the so-called energy-efficient fluorescent lamps, having a more efficient electrode design and an improved phosphor. This made it possible to produce lamps with reduced power (18 W instead of 20 W, 36 W instead of 40 W, 58 W instead of 65 W), a bulb diameter reduced by 1.6 times and increased luminous efficiency.

White light lamps of the LB type provide the highest luminous flux of all listed types of lamps of the same power. They approximately reproduce the color of sunlight and are used in rooms where significant visual strain is required from workers.

Lamps of warm white light of the LTB type have a pronounced pink tint and are used when there is a need to emphasize pink and red tones, for example, when rendering the color of a human face.

The color of fluorescent lamps of the LD type is close to the color of fluorescent lamps with corrected color of the LDC type.

Cold-white light lamps of the LHB type occupy an intermediate position in color between white light lamps and daylight lamps with corrected color and in some cases are used on a par with the latter.

The average burning time of fluorescent lamps is at least 12,000 hours.

Luminous flux of each lamp after 70 % The average burning time must be at least 70% of the nominal luminous flux.

The average surface brightness of fluorescent lamps ranges from 6 to 11 cd/m2. The luminous efficiency of LB type lamps ranges from 50.6 to 65.2 lm/W.

Fluorescent lamps, when connected to an alternating current network, emit a luminous flux that varies over time. The pulsation coefficient of the luminous flux is 23% (for LDC type lamps - 43 %). As the rated voltage increases, the luminous flux and power consumed by the lamp increase.

Erythematic and bactericidal fluorescent lamps are also produced. Their flasks are made of special glass that transmits ultraviolet radiation. Erythema lamps use a special phosphor that converts mercury discharge radiation into ultraviolet radiation with a range of wavelengths that most cause tanning (erythema) of human skin. Such lamps are used in installations for artificial ultraviolet irradiation of people and animals. Germicidal lamps used in air disinfection installations; These lamps do not have a phosphor.

Fluorescent lamps are designed for normal operation at ambient temperatures of +15...+40 °C. If the temperature drops, the pressure of argon and mercury vapor drops sharply and the ignition and combustion of the lamp deteriorate.

The duration of operation of the lamp is longer, the fewer times it is turned on, i.e., the less the oxide layer of electrodes wears out. A decrease in the voltage supplied to the lamp, as well as a decrease in ambient temperature, contribute to more intensive wear of the electrode oxide. If the voltage decreases by 10-15%, the lamp may not light up or its inclusion will be accompanied by repeated blinking. Increasing the voltage makes it easier to ignite the lamp, but reduces its light output.

Disadvantages of fluorescent lamps: a decrease in the power factor of the electrical network, the creation of radio interference and a stroboscopic effect due to pulsation of the light flux, etc.

The stroboscopic effect consists of creating in a person under fluorescent lighting the illusion that an object moving (rotating) at a certain speed is at rest or moving (rotating) in the opposite direction. In production conditions, this is dangerous to human life and health. At the same time, the stroboscopic effect is used to check the correct operation of electricity meters. There are depressed depressions (marks) on the rotating disk of the electric meter. If you look at the disk from above, illuminated by fluorescent light, then if the disk moves correctly, it seems that the recesses (marks) are at rest.

To eliminate stroboscopy phenomena, reduce radio interference, and improve power factor, special circuits for switching on fluorescent lamps are used.

1.3. High pressure fluorescent lamps

High-pressure mercury lamps of the DRL type (mercury arc fluorescent) are produced with a power of 50, 80, 125, 175, 250, 400, 700, 1000 and 2000 W.

A DRL lamp consists of an ellipsoidal glass cylinder (flask), on the inner surface of which is applied a layer of phosphor - magnesium fluorogermanate (or magnesium arsenate). To maintain the stability of the properties of the phosphor, the cylinder is filled with carbon dioxide. Inside the glass cylinder (flask) there is a quartz glass tube filled with mercury vapor under high pressure. When an electrical discharge occurs in the tube, its visible radiation passes through a phosphor layer, which, by absorbing ultraviolet radiation from the quartz discharge tube, turns it into red visible radiation.

The average operating time of DRL lamps ranges from 6,000 hours (lamps with a power of 80 and 125 W) to 10,000 hours (lamps with a power of 400 W or more).

For DRL lamps, the percentage of red radiation is also regulated (6 and 10%). The rated network voltage for all DRL lamps is 220 V. The pulsation coefficient of DRL lamps is 61-74%.

The most modern light sources include metal halide lamps, in which sodium, thallium and indium iodides are added to the mercury discharge in order to increase the luminous efficiency of the lamps. Metal halide lamps of the DRI type (mercury-iodide arc) have ellipsoidal or cylindrical bulbs, inside of which a quartz cylindrical burner is located. Inside this burner, a discharge occurs in vapors of metals and their iodides.

The power of DRI lamps is 250, 400, 700, 1000, 2000 and 3500 W. The luminous efficiency of DRI lamps is 70-95 lm/W.

The luminous efficiency of high-pressure sodium lamps reaches 100-130 lm/W. These lamps have a discharge tube made of floor and crystalline aluminum oxide, inert to sodium vapor and highly transmitting its radiation, placed inside a glass cylindrical flask. The pressure in the tube is about 200 kPa. At this pressure, the sodium resonance lines expand, occupying a certain spectral band, as a result of which the color of the discharge becomes whiter. The operating time of the lamps is 10-15 thousand hours.

To illuminate large areas, powerful (5, 10, 20 and 50 kW) xenon tubular ballastless lamps of the DKsT type are used. They are ignited using a starting device that generates a high-voltage (up to 30 kV) high-frequency voltage pulse, under the influence of which a discharge occurs in the xenon lamp.

Lamps with a power of 5 kW have a nominal voltage of PO V, with a power of 10 kW - a voltage of 220 V, with a power of 20 and 50 kW - a voltage of 380 V. The luminous efficiency of these lamps is from 17.6 to 32 lm / W.

2. Power supply circuits for fluorescent lamps

Fluorescent lamps are connected to the network in series with an inductive reactance (choke), which ensures stabilization of the alternating current in the lamp.

The fact is that an electric discharge in a gas is unstable, when minor voltage fluctuations cause a sharp change in the current in the lamp.

There are the following lamp power supply schemes: pulse ignition, fast ignition, instant ignition.

In the pulse ignition circuit (Fig. 1), the ignition process is provided by a starter (starter). Here, the electrodes are first heated, then an instantaneous voltage pulse occurs. The starter is a miniature gas-discharge light bulb with two electrodes. The bulb bulb is filled with the inert gas neon. One of the starter electrodes is rigid and stationary, and the other is bimetallic, bending when heated. In normal condition, the starter electrodes are open. At the moment the circuit is connected to the network, the full network voltage is applied to the electrodes of the lamp and starter, since there is no current in the lamp circuit and, therefore, the voltage loss in the inductor is zero. The voltage applied to the starter electrodes causes a gas discharge in it, which in turn ensures the passage of a small current (hundredths of an ampere) through both lamp electrodes and the inductor. Under the influence of the heat generated by the passing current, the bimetallic plate, bending, short-circuits the starter, as a result of which the current strength in the circuit increases to 0.5-0.6 A and the lamp electrodes quickly heat up. After the starter electrodes close, the gas discharge in it stops, the electrodes cool down and then open. An instantaneous break in the current in the circuit causes the appearance of an electromotive force of self-induction in the inductor in the form of a voltage peak, which leads to the ignition of the lamp, the electrodes of which by that moment are red-hot. After lighting the lamp, the voltage at its terminals is about half the network voltage. The rest of the voltage is extinguished at the inductor. The voltage applied to the starter (half the mains voltage) turns out to be insufficient to trigger it again.

Rice. 1. Pulse circuit for connecting a fluorescent lamp to the network:

1 – starter (starter); 2 – lamp; 3 – throttle.

In the fast ignition circuit (Fig. 2), the electrodes of the lamps are connected to separate windings of a special incandescent transformer. When voltage is applied to a non-burning lamp, the voltage loss in the inductor will be small, the increase in voltage of the filament windings is completely applied to the electrodes, which quickly and strongly heat up, and the lamp can light up at normal mains voltage. When a discharge occurs in the lamp, the filament current of the ballast automatically decreases.

Rice. 2. Scheme for fast ignition of a fluorescent lamp:

1 – throttle; 2 – lamp; 3 – filament transformer.

The instant ignition circuit (Fig. 3) uses a choke-transformer and a separate resonant circuit, which creates an increased (6-7 times more than the operating) voltage on the lamp at the moment of switching on. Instant ignition circuits are used only in certain cases, for example in explosive areas with lamps containing special reinforced electrodes. Electrodes of normal type lamps in the circuit shown in Fig. 3, wear out quickly. The high voltage supplied to the lamp at the initial moment poses a danger to operating personnel.

Rice. 3. Diagram of instant ignition of a fluorescent lamp

1 – lamp; 2 – capacitor; 3 – choke-transformer.

When the throttles operate, noise occurs. To provide the required current and voltage at the lamp terminals in starting and operating modes, increase the power factor, reduce the stroboscopic effect and reduce the level of radio interference, special ballasts are attached to fluorescent lamps. The ballasts include chokes, capacitors (to increase the power factor and suppress radio interference) and resistances, placed in a common metal casing and filled with bitumen mass.

According to the ignition method, ballasts are divided into three groups: starter (symbol UB), fast and instant ignition (symbol AB).

The main types of ballasts for fluorescent lamps: 1UBI-40/220-VP-600U4 or 2UBI-20/220-VPP-110HL4, which means the following: the first digit indicates how many lamps are switched on with the device; UB - starter control gear; I - inductive phase shift of the current consumed by the device (can be E - capacitive or K - compensated, i.e. compensating the stroboscopic effect); 40 and 20 - lamp power, W; 220 - supply voltage, V; B - built-in device (maybe N - independent); P - with reduced noise level; PP - with especially low noise level; 600 and software - series number or modification of the ballast; U and HL - the ballast is designed for operation in areas with a temperate or cold climate, respectively (can also be TV - tropical humid climate; TC - tropical dry climate; T - tropical wet and dry; 0 - any climate on land); 4 - placement in rooms with an artificially controlled climate (maybe 1 - in the open air; 2 - rooms poorly isolated from the surrounding air, and canopies; 3 - ordinary naturally ventilated rooms; 5 - rooms with high humidity and unventilated underground rooms).

Ballasts for arc mercury fluorescent lamps (MAFL), arc mercury iodide lamps (MAI), high-pressure sodium lamps (HPL) are designated as follows: 1DBI-400DRL/220-N or 1DBI-400DNaT/220-V. Here DB is a ballast choke; DRL and DNAT - type of lamp (DNaT means the same as NLVD); N - independent ballast.

Electrical diagram starter two-lamp ballasts is given in Fig. 4.

Rice. 4. Electrical diagram of starter ballast 2 UBI for two lamps

1 – throttle; 2 – lamps; 3 – starters.

Ballasts for arc mercury fluorescent lamps of the DRL type are made with a choke (Fig. 5).

Fig.5. Scheme for switching on DRL type lamps through a choke.

1 – throttle; 2 – lamp; C – capacitor.

To turn on DRI and HPS lamps, ballasts with standardized pulse ignition devices are used, the main elements of which are diode thyristors (Fig. 6). Here, however, restarting a lamp that has gone out and is not equipped with a special instant re-ignition unit is possible only after it has cooled, i.e. after 10-15 minutes.

Fig. 6 Connection diagram for lamps of the DRI or HPS type.

1 – pulse ignition device; 2 – ballast choke

3. Basic lighting quantities

The amount of light emitted by a source is called luminous flux and is designated F. The unit of luminous flux is lumen(lm).

The luminous flux contained within the solid angle , at the vertex of which a point light source of force J is located, is determined by the formula Ф = J.

The power of light J is the luminous flux density in one direction or another; measured in candelas (cd).

Candela is the luminous intensity emitted from an area of ​​1/600,000 m 2 of the cross-section of the full emitter in a direction perpendicular to this cross-section, at an emitter temperature equal to the solidification temperature of platinum (2045 K) and a pressure of 101,325 Pa.

Solid angle in is equal to the ratio of the surface area o, cut out on a sphere by a cone with its vertex at point S, to the square of radius r (Fig. 2.1). If r = 1, then the solid angle is numerically equal to the surface area cut out by a cone on a sphere of unit radius. The unit of solid angle is steradian(Wed).

Thus, a lumen is the product of a candela and a steradian. The illumination of the working surface will be better, the greater the luminous flux falling on this surface. The degree of surface illumination, i.e. the density of the luminous flux onto the illuminated surface, is characterized by illumination E, which is measured in suites(OK). If a luminous flux equal to 1 lm falls on 1 m 2 of any surface, then the illumination E will be 1 lux, i.e. lm/m2.

When the working surface is illuminated, light and dark details stand out in it, differing in their brightnessI., which depends not only on illumination, but also on the reflective properties of the surface. Brightness determines the sensation of light received by the eyes. If the brightness of the surface is very low, it is difficult to discern details on it, and vice versa, if the brightness is very high, then the surface will blind the eyes. Brightness is equal to the ratio of luminous intensity to the projection area of ​​a reflecting (emitting) body in a given direction; measured in candelas per square meter (cd/m2).

4. Safety precautions when servicing electric lighting installations

The organization of safety work at electrical installation work sites provides for: the appointment of persons responsible for the safety of work (work foreman, site supervisors, foremen and foremen of installation teams); instruction on safe methods work in the workplace; hanging warning posters, installing fences, assigning people on duty when performing installation work that is dangerous to others.

All installation work on or near live parts must be carried out with the voltage removed.

When installing electrical installations, various machines, mechanisms and devices are used to facilitate the work of installers and ensure safe working conditions. Incompetent handling of these mechanical equipment can cause injuries.

In electrical installation practice, special vehicles and mobile workshops are widely used. Thus, a special SK-A type vehicle with a trailer is designed for transporting and laying cables in earthen trenches. To install overhead lines, telescopic towers are used, equipped with a basket in which the installer can be lifted to a height of up to 26 m. To lift supports and parts of overhead line structures, jib cranes on wheels and tracks are used.

For electrical installation work, electrified working tools are used. According to protective measures against damage electric shock electrified hand tools are divided into 3 classes:

Class I - machines with insulation of all live parts; the plug has a grounding contact;

Class II - machines in which all live parts have double or reinforced insulation; these machines do not have grounding devices;

Class III - machines with a rated voltage not higher than 42 V.

The rated voltage of AC machines of classes I and II should not exceed 380 V.

Electrified tools include:

Drilling manual electric machines with both commutator single-phase motors for a rated voltage of 220 V, and with three-phase asynchronous motors for a rated voltage of 36 and 220 V;

An electric hammer designed for punching openings and niches in brickwork and concrete when installing passages through walls and ceilings, when installing group panels and shields in the case of hidden electrical wiring (rated voltage of the electric motor is 220 V);

An electric hammer drill designed for drilling deep holes with a diameter of up to 32 mm in the walls and ceilings of buildings made of brick or concrete to a depth of up to 700 mm;

An electric furrow cutter designed for cutting furrows in brick walls for laying hidden electrical wiring (the width of the cut furrow is 8 mm and the depth is 20 mm).

Workers who have completed industrial safety training are allowed to work with manual electric machines. Each machine must have an inventory number.

Hand-held electrical machines must not be used in explosive areas, as well as in areas with a chemically active environment that destroys metal and insulation.

Machines that are not protected against splashes are not permitted to be used in open areas during rain or snowfall.

Before working with the machine, it is necessary to check the completeness and reliability of fastening of the parts, the serviceability of the cable (cord) and plug, the integrity of the insulating parts of the case, the handle and brush holder covers, the presence of protective covers, the operation of the switch and the operation of the machine at idle speed. When operating Class I machines, it is necessary to use individual electrical protective equipment (dielectric gloves).

To change the cutting tool, make adjustments, when carrying a manual machine and taking breaks in work, it must be turned off.

It is prohibited to operate a manual electric machine if at least one of the following faults is present: damage to the plug connection, cable (cord) or their protective tube; damage to the brush holder cover of a machine with a commutator electric motor; unclear operation of the switch; the appearance of smoke, an all-round fire on the collector, a pungent smell of burnt insulation; lubricant leakage; increased knocking, noise, vibration; breakage or cracks in the body, handle or protective guard; breakage of the cutting tool.

Work on the installation of overhead power lines (external lighting networks) involves lifting people and materials to heights using lifting machines and mechanisms. In this case, there is a danger of injury in case of falling from supports or other structures, as well as injury from lightning current when working during a thunderstorm or induced voltage from neighboring lines.

While lowering the lower end of the support into the pit, none of the workers should be in it. Climbing to the support should be carried out using a telescopic tower, assembly claws, manholes, and ladders. To avoid bruises and injuries as a result of parts and tools falling from a height, it is prohibited to be under the support and basket of the tower during work, and it is not allowed to throw any objects from the height of the support.

When rolling out bare wire from a drum, the worker must wear canvas gloves. During the installation of lines longer than 3 km, the installed sections of wires must be short-circuited and grounded in case induced voltage appears in this section from neighboring lines or from a thundercloud.

To lay cables along walls or building structures at a height of 2 m or more, durable scaffolding with fencing in the form of railings and a side board (at the deck) should be used. Cable laying from stairs is not permitted. Lifting the cable to secure it on the supporting devices of the cable structure to a height of more than 2 m must be done using slingshots and hand blocks. At turning angles cable line When unrolling, do not pull the cable by hand. When heating the cable in winter with an electric current of 220 V, its sheath must be grounded to avoid electrical injuries in the event of a short circuit of the current-carrying conductor to steel armor or aluminum (lead) sheath.

Time-tested incandescent lamps were anathema in our country, but despite the predominance of “economical” light sources in the assortment of electrical goods stores, they are still on the shelves and are in steady demand.

Of course, their design, which has undergone virtually no changes over almost a hundred years of its existence, may seem archaic to some and make them want to modernize so that they consume less electricity, burn out less often and, in general, behave in a “modern” way. Are there possibilities for this? Yes, I have.

One way to modernize an “old lady” incandescent lamp is to include a special control device - a dimmer - in its power circuit. This anglicism comes from the word “to dim,” and the device is engaged in smoothly reducing the brightness of the lamp.

In order to reduce the brightness of the glow, you need to reduce the amount of voltage supplied to it. You can do this in two ways:

1. dissipate electrical energy as it approaches the lamp;
2. use the supply voltage to start the regulated device.

You can dissipate electrical energy and prevent it from reaching the lamp fully ordinary rheostat. There were many such miniature devices in tube and semiconductor televisions, where they made various adjustments. For example, sound. If the rating of a small rheostat is designed for 220 volts, then it will easily extinguish any energy from the household network. The only question is that it will get very hot, because the law of conservation of energy has not yet been canceled.

The degree of heating can be reduced by using a larger rheostat, for example ballast household transformer, which is included in the power circuit of an electrical appliance to compensate for temporary voltage surges. Having a large switch on each switch is not a very aesthetic solution. In addition, energy dissipation does not solve the main problem - energy saving. When the rheostat is turned on, even if the light bulb is shining at full intensity, the counter will spin at the same speed.

In order to really save electrical energy, it is necessary to place between the switch and the switch a device powered from the network, the output power of which can be adjusted. They may be self-oscillation generator, since the filament in the lamp does not distinguish the subtleties of the origin of the current, the main thing for it is that it be alternating.

Self-oscillations - what is it?

In radio and electrical engineering, there are a number of circuit solutions that allow you to change the direction of the output current. These changes in direction can continue as long as there is a supply voltage at the input of the device. That's why they are called self-oscillations.

If you connect an oscilloscope to the output of the self-oscillating generator, then on its screen you will see something similar to a sine wave. Although externally similar to what it produces, these fluctuations have a completely different nature. In fact, it is a series of impulses changing sign.

Electrical devices are quite crude; they do not distinguish a train of pulses from a sine wave and work perfectly well with them. A striking example of such “deception” is the recently widespread use of high-frequency self-oscillations, due to which the transformer of the device was reduced several times.

Here is such a self-oscillation generator (only much smaller in size), which produces a train of pulses with a frequency of 50 Hz, and is connected to the power circuit of an incandescent lamp. When creating a dimmer circuit for an incandescent lamp, modern semiconductor devices are used - thyristors, dinistors and triacs.
They make it possible to most simply control the moments of unlocking and locking, thereby changing the direction of the current in the circuit and generating self-oscillations. However, there are transistor-based self-oscillation generators, which are based on a pair of powerful field elements. They also use a circuit through a protection unit.

Pros and cons of incandescent lamp dimmers

Each device or device has a sum of advantages and disadvantages, and incandescent lamp dimmers also have them.

The main, but perhaps the only advantage of this device is that it allows you to adjust the brightness of the glow without causing side heating. Does it significantly save electrical energy and increase lamp life? Judge for yourself:

• to operate the self-oscillation generator, alternating current is converted into direct current (there is a diode bridge at its input), so the total efficiency of the device is even lower than that of a conventional lamp;
• an incandescent lamp, when operating outside the rated voltage, also has a lower efficiency;
• if the initial voltage of the device is more than 30 percent of the nominal 220 volts, then the initial surge of current when turned on is almost the same as when operating from a regular network.

It seems that under such conditions the use of a dimmer is a purely aesthetic whim.

The train of pulses produced by the dimmer is a source of radio interference. And the shorter the pulse or the higher the repetition rate, the wider the range of additional harmonics.
This is a physical law and cannot be changed. To compensate for this trouble, LC filters (coils with capacitors) are introduced into the device circuit. If high-power lamps with a long filament are added, then at a minimum voltage they can begin to “sing” - precisely because of the additional harmonics.

Dimmers for incandescent lamps must strictly not be connected to the power supply circuits of computers, televisions, radios, or electronic ballasts. In general, if you have a “dimmer” included in the control circuit of the lighting device, when purchasing lamps you should pay attention to whether it can be dimmed.

What types of dimmers are there?

Despite all the shortcomings of these devices, they are widely used. Firstly, because there are still some savings from their use, and secondly, the aesthetic effect cannot be written off.

For a consumer unfamiliar with electrical engineering, the main difference between these devices is the control method. The simplest models have a control knob located on the dimmer body. If someone does not like the handle, then there are models with touch controls.

The most expensive of them have remote control - for example, from a remote control that looks like a “lazy guy” that controls the TV.
Based on the principle of operation, such remote controls differ in whether they operate via a radio or infrared channel. The most exotic dimmers are triggered by voice, the presence of a person in the room - control using an open capacitive circuit or heat sensors.

Currently, many leading manufacturers of electrical equipment, such as Schneider Electric, Feller, OSRAM and others, have begun producing dimmers not only for incandescent lamps, but also for fluorescent light sources.

An example of adjusting the brightness of a lamp using a dimmer in the video