What are lumens and how to convert them to watts? How many lumens and what is the luminous flux in the lamp? What is luminous flux

AT Soviet times When choosing a light bulb, consumers were guided by the number of watts in it. The more of them - the brighter this device shone. However, today (when many new varieties of lamps have appeared on store shelves), we increasingly come across such a concept as “lumen”. What is it, how does it differ from a watt, and what is the unit called lumen per watt? Let's find the answers to these questions.

What is "lumen"

In the middle of the twentieth century. to avoid confusion in units of measurement between different countries, the universal SI system was introduced. It is thanks to her that we have watts, amperes, meters, kilograms, etc.

According to her, (visible electromagnetic radiation) is. In fact, these units measure the amount of light emanating from its source.

Also, to the question of what “lumen” is, you can answer that this is the name of a famous Russian rock band from Ufa. Having started its activity in 1998, for almost twenty years it continues to be loved by many listeners in Russian Federation and beyond.

Origin of the word

Having learned what a lumen is, it is worth clarifying where this word came from in the Russian language.

Like most of the names of units of measurement in the SI system, the term in question is Latinism. It is derived from the word for "light" (lūmen).

At the same time, some linguists argue that the noun could also be formed from the Proto-Indo-European word leuk (white) or from lucmen (the meaning is not exactly established).

What is the difference between lumen and lux

Considering the meaning of the word "lumen", it is worth mentioning such a concept close to it as "lux".

Both of these terms refer to light energy units, however, lumens is all the light emitted by the source, and lux is the amount that reached the illuminated surface, and was not stopped by some kind of obstacles with the formation of shadows.

The interdependence of these units can be reflected in the following formula: 1 lux = 1 lumen / 1 square meter.

For example, if a lamp illuminating an area of ​​1 m 2 emits 50 lumens, then the illumination this place equal to 50 lux (50lm / 1m 2 \u003d 50 lux).

However, if the same lamp with the same amount of light is used for a room of 10 m 2, then the illumination in it will be less than in the previous case. Only 5 lux (50lm/10m 2 = 5 lux).

In addition, such calculations did not take into account the presence of various obstacles that prevent the light rays from reaching the surface, which significantly reduces the level of illumination.

In connection with this situation, in any country in the world there are lighting standards for various buildings. If it is below them, a person's vision does not receive enough light and deteriorates. For this reason, when planning to make repairs or rearrangements in your home, it is always important to take this nuance into account.

There are also a number of design programs in which such calculations are made automatically.

Lumen and watt

Having learned the difference and meaning of lumen and lux, you should pay attention to another unit of the SI system - watt.

Due to their use for light bulbs, some believe that these units can be freely correlated with each other. However, this is not quite true.

The fact is that in watts the power of energy that a light bulb consumes is measured, and in lumens it is the amount of light that it emits.

During the existence of only incandescent lamps, it was easier to calculate the amount of light from such a device. Since a 100 W light bulb gave out about 1600 lm of light. While a similar device at 60 W - 800 lm. It turned out that the more energy consumed, the better the lighting.

But today it's not like that. In recent decades, several new types of lighting sources have been invented (luminescent, etc.). Their advantage is economy. That is, they shine brighter with less energy used.

In this regard, if necessary, to draw up a relationship between watts and lumens, you need to take into account the type of lamp and look for its luminosity in special tables.

It is worth noting that ordinary person sometimes you don’t want to rebuild and understand all these subtleties. Therefore, most domestic manufacturers of new-type light bulbs on the labels indicate not only the number of lumens, but how much less watts this device consumes (compared to an incandescent lamp). For example: a 12 watt lamp produces light as at 75 watts.

The unit of measure "lumens per watt": its meaning and scope

For example, a classic 40 W incandescent lamp has a light output of 10.4 lm/W. At the same time, for an induction lamp with the same power, this figure is much higher - 90 lm / W.

For this reason, when choosing a lighting device for your home, you should still not be too lazy, but find out the level of its light output. As a rule, such data is on the labels.

Ten years ago, choosing the right light bulb was easier, because incandescent bulbs were marked with maximum power. Currently, new LED-lamps are gaining more and more popularity. Finding the right wattage in today's lighting era is more difficult, as LEDs, CFLs, and other energy-saving lamps have completely changed wattage. Now it will not be entirely correct to focus on watts, and it is not always possible. If in a regular store a specialist can still help you choose the right light bulb, then when you make a purchase via the Internet, you are unlikely to find a watt in the description of this light bulb.

What is luminous flux?

Watts refer to the amount of energy consumed. For example, a 100W light bulb uses more energy than a 60W light bulb. This value indicates how much energy will be spent - it does not indicate the amount of light rays that the lamp gives. How much light you get from a light bulb shows 1 lumen.

Lumen is a unit of measurement luminous flux in the system of calculus. The brighter the light bulb, the larger this value will be. For example, a conventional 40 W incandescent lamp has a luminous flux of 300 lumens. Converting lumens to watts is not as easy as it seems.

The packaging of each product must contain information about how much light this product gives. When electrical energy is converted into light rays, some of it is lost and therefore large values ​​are not achieved. It can be seen that this indicator of incandescent lamps is 12 lumens per watt, while fluorescent lamps give 60 lumens per watt. LED lamps provide maximum illumination with minimum energy consumption - up to 90 lumens per watt.

Using this approach, it is not always possible to get the right results, because even bulbs of the same type with the same power can have a different ratio of luminous flux to energy costs, and the difference can be quite significant. Below is a table that allows you to convert watts to lumens for a lamp on first use. With its help, you can easily find out how many lumens are in an incandescent lamp, for example.

It follows from the table that a 600 lm LED lamp is not the equivalent of a 60 W incandescent lamp, and 1,000 lm is not the equivalent of a 100 W incandescent lamp.

Parameters that determine the luminous flux and its calculation

The beam consists of a stream of particles - photons. When these particles enter a person's eyes, certain visual sensations arise. The more photons hit the retina in a certain period of time, the more illuminated the object seems to us. Thus, the lamps emit a luminous flux of photons, which, falling into the eyes, allow us to clearly see objects in front of us.

Unfortunately, the longer the light bulb is used, the less brightness it can give. The lamp itself can also worsen the illumination indicator, because often the losses depend on the quality of the lamp material. The largest losses of luminous flux are observed in gas-discharge sources, for fluorescent lamps these losses can be 20–30%, for incandescent lamps - 10–15%. LED lamps have the highest light output - light loss is less than 5%.

To convert the luminous flux of a lamp to lumens, use the average light output values:

• for diode products, multiply the power by 80–90 lm / W for light bulbs with a frosted bulb and get the light flux;
• for diode filaments (transparent products with yellow stripes) multiply the power consumption by 100 lm/W;
• multiply fluorescent energy-saving lamps by 60 lm / watt;
• for a HPS lamp, this value will be 66 lm / W for 70W; 74 lm/w for 100W, 150W, 250W; 88 lm/w at 400W;
• for an arc mercury lamp, the multiplier will be 58 lm / W;
• a 100 W incandescent lamp produces approximately 1,200 lumens. If the power is reduced to 40 W, the flux will reach 400 lm. But a 60 watt light bulb has an indicator of about 800 lm.

If you need to accurately determine the luminous flux, you will need a luxmeter device. It can be used to calculate , what luminous flux will be at the selected points of the room according to a known method.

One lux corresponds to a certain luminous flux falling on an illuminated surface of one square meter. You can determine the approximate value of the luminous flux created by a particular source using the formula:

F \u003d E x S,
where S is the area of ​​all surfaces of the room you are examining (in square meters), and E is the illumination (in lux).

So if the surface area is 75 sq. meters, and the illumination is 40 lux, the luminous flux is 3,000 lumens. To accurately calculate the luminous flux, many other spatial factors will have to be taken into account.

If you are correct, in all respects you will select led lamp, subject to all the requirements of the manufacturer, it is guaranteed to serve for many years. Currently, the least energy-consuming and most illuminating products are not cheap, but over time they will become available to all consumers.

The European corporation Vacon Group, established in 1993, specializes in the development, production and implementation of frequency converters for controlling asynchronous motors (if necessary, each model can also operate in V / f mode) and is one of the world leaders in the converter technology market.

It produces low-voltage frequency converters in the power range of 0.75…5000 kW for a voltage of 208…690 V, and high-voltage converter systems in the power range from 300 kW to 4 MW and voltages of 3…10 kV.

A distinctive feature of the products is high reliability in the most difficult operating conditions in a wide temperature range of -10 ... 50 ° C.

The model range of low-voltage models is represented by well-known series NXL and NXS for building systems without feedback, NXP and NXC - for systems with an encoder, as well as new models and

Compact and functional frequency converter with a power of 0.25 ... 30 kW for voltages of 208 ... 500 V for use in industry and public utilities(Fig. 1).

Rice. one.

Compact design, IP20, IP21 and IP54 enclosure ratings, flexible control and programming options provide the best solution for any application. A high degree of protection allows you to mount the units on the wall without additional cabinets. RFI filters and brake choppers are built in by default. Standard blocks can be used almost everywhere: both in industrial facilities and in residential areas. The built-in AC choke is an effective means of protecting the drive from surges and limits overloading of power transformers, cables and fuses.

Characteristics and features:

• Built-in EMC filter;
• Minimum parameterization - flexible universal macro program with optimized parameter settings, specialized macro programs;
• Panel with a seven-segment display, indication of units and drive status;
• Wide range of control options (via inputs/outputs via interface buses or from the control panel);
• Large number of functions (eg fully programmable I/Os, automatic identification, PID controller, flying start);
• Specialized macro programs;
• Possibility to install additional boards with I/O.

Compact frequency converters for intensive operation with a power of 0.37 ... 560 kW for voltages of 208 ... 690 V (Fig. 2).

Rice. 2.

One of key features A reliable design of these converters is effective protection against interference in the supply network. Uninterrupted operation is guaranteed intelligent control and protection of the motor and drive mechanism, the use of quality components and efficient cooling. With IP21 and IP54 enclosure ratings and built-in EMC filters, Vacon NXS can be used in any environment.

A standard All-in-One application package with a download wizard function will help you easily set the required operating parameters for the converter for any application.

A feature set of standard I/Os, as well as the ability to install up to five I/O cards, including a variety of fieldbus interfaces, provides flexible control of the transmitter. The user can independently choose the required configuration by installing the necessary boards in the five slots of the converter. The control unit can be connected to an external 24 V power supply, which allows uninterrupted control even when the mains voltage is turned off (for example, to maintain a fieldbus communication line, control other devices or parameterize).

Characteristics and features:

• High PWM switching frequency;
• Vector control without feedback;
• Temperature regulation of the built-in fan;
• Built-in EMC filter;
• Built-in AC choke at the input;
• Fast and accurate start-up with the "setup wizard" function;
• Built-in PID controller and the ability to control up to five pumps;
• Special set of macro programs (for high-speed applications, elevator control programs, synchronization programs, etc.);
• Possibility to install up to five interface expansion boards (Modbus, Profibus, BacNet, Enthernet);
• High speed applications (up to 7200Hz).

Modular structure software allows you to replace the set of drive control programs.

As a result, along with the frequency converter, you get a ready-made package of software applications that you need, developed by Vacon specialists using the toolkit Vacon NC61131-3 Engineering for a wide variety of standard drive applications. There are several ready-made software packages:

• The basic All-in-One application package includes seven programs. The choice of the program is set either by one parameter, or, in the case of the first connection to the network, the request for the active program is carried out by the “download wizard”. This is sufficient for configuring I/O signals for a typical application, such as dual control room operation, constant pressure control with the converter's PID controller for stepping speed, or controlling a "fan" load. In most cases, the factory parameter configuration is optimal, and only motor and frequency range input is required.
• The “Water” package is specially designed to control pumping units of sewage, water and heat supply systems.
• The "Standard Lift" package is designed for elevators and lifts.
• Fire mode PID package for fire extinguishing systems - the frequency converter continues to operate in critical conditions until a fatal failure.
• Package "High speed" for work with high-speed engines (up to 1900Hz), etc.

Frequency converters that combine high precision and dynamics of control with high power and equipment reliability (Fig. 3). Vacon NXP are available in the power range 0.25…5000 kW and voltage 208…690 V.

Rice. 3.

The Vacon NXP control unit allows you to solve any tasks from the field of variable speed drive. You can choose the required I/O configuration by installing the necessary I/O boards in the five slots of the converter. Vacon NXP drives can control both squirrel-cage and permanent magnet motors in closed and open loops. Special applications are also possible, for example for high-speed asynchronous motors. Incremental encoders, absolute encoders and resolvers are used to implement closed loop control. To ensure high-speed information exchange between frequency converters, fiber-optic communication is used using the high-speed Vacon SystemBus protocol. All Vacon NXP drives contain an integrated PLC. Custom applications are implemented in the Vacon NC61131-3 Engineering environment and provide additional drive functionality, resulting in lower system cost.

Vacon NXP also has the option to replace the drive control suite. Alternatives to the standard All-in-One package include:

System interface software package. This application program has a flexible and logical interface for connecting to group drive control systems. Typical areas of application of this program are system drives of paper machines, group drives of technological lines in metallurgy and other industries, groups of drives "Master-Slave".

Position Package - Allows the Vacon NXP actuator to be used as a complete single axis position controller. The application allows you to enter custom position units, set an arbitrary choice of the initial position, use automatic zero position search, absolute and relative positioning, use software and hardware "limit switches".

Synchronization package - allows you to control the position of the slave axis depending on the position of the master axis with the ability to adjust the gear ratio. The position of the master axis is set via the input of an additional encoder. The transmission coefficient can be changed "on the go" by external signals "more", "less".

The elevator control package contains all the functions necessary for the implementation of the elevator control system and the functions that allow you to quickly and easily commission and configure the elevator drive:

• Support for asynchronous and servo motors,
• Lift speed in [Hz] and in [m/s],
• Built-in electromagnetic brake control system,
• Emergency evacuation function. (In the event of a power failure, the elevator car will reach the nearest floor),
• Built-in power contactor control system.

The High Speed ​​Motor Package allows Vacon NXP to be used to control high speed applications such as turbochargers and high speed spindles.

The marine drive package provides specific features and options that make it easier to use the drive on ships.

Vacon NXP also provides options to increase the security of the overall system and to simplify the system in terms of special external devices and cabling, using the protection functions built into the drive, including safety interlock. Traditionally used contactors or circuit breakers can be omitted when using the Vacon drive. This drive function is certified to EN954-1 Category 3.

Vacon NXP uses an ATEX certified 94/9/EC thermistor input to measure the temperature of Ex motors in potentially explosive areas. This option is usually implemented using external relays and contactors, and eliminating them when using the Vacon drive reduces the cost of the system.

Characteristics and features:

• Statistical speed error<0,01%;
• Work with incremental and absolute encoders;
• Full torque control over the entire speed range;
• Control of asynchronous motors and motors with permanent magnets;
• Dynamic open-loop and closed-loop vector control;
• High-speed communication channel between converters;
• Built-in brake chopper (up to 30kW);
• Built-in EMC filter;
• Built-in AC choke at the input;
• Ability to operate master-slave systems;
• Possibility to install up to five interface expansion boards ( Modbus, Profibus, BacNet, Ethernet);
• High speed applications (up to 7200Hz);
• A variety of application programs for any application;
• Wide possibilities of communication with external devices;
• Higher control accuracy and advanced programming features compared to Vacon NXS.

Cabinet-mounted frequency converters are a continuation of the NXP line of converters in the high power range (Fig. 4). They take full advantage of NXP's strengths in reliability, ease of use, and design and programming flexibility. In addition to the converter, the Vacon NXC cabinet can include many options, such as input protection and switching devices, additional controls, and output filters. When ordering, each option is selected by adding a specific code to the order specification.

Rice. 4.

The Vacon NXP control module used in the NXC is physically completely separated from the power section. It is cabinet-mounted on a separate mounting plate that has enough space for additional devices such as relays or contactors. Terminals for connecting power and control cables are convenient and accessible.

Frequency converters comply with EMC standards, which guarantees reliable operation without affecting the surrounding equipment.

Vacon NXC cabinet drives with regenerative power supply are ideal for applications where either high demands are placed on the quality of the sinusoidal current drawn from the network, or there are modes of energy transfer to the network. This drive is fully compliant with the IEEE-519, G5/4 standard, subject to proper installation and connection. The low coefficient of current harmonic distortion (THDi) ≤ 5% allows to reduce the effective value of the consumed current and reduce the dimensions of the supply transformers and switching and protective devices, as well as the cross section of the power cable. An additional advantage of such a drive in terms of dimensions and installation work is also the absence of the need for a braking resistor.

The power factor cos j of the energy consumed by the drive can be adjusted over a wide range, which allows minimizing the reactive power consumed by the system as a whole. Vacon NXC's wide range of options provides maximum drive configuration flexibility and expands the range of applications. The options are divided into several categories and can be combined with each other to adapt the drive to any application.

The range of Vacon frequency converters continues to expand. Recently, it has been replenished with new models and Vacon 10 Machinery.

Frequency converters, which are the third generation of Vacon drives and a logical continuation of the chain of frequency converters of the NXS and NXP series (Fig. 5). This series incorporates the best features of its predecessors and is designed for specialized HVAC and industrial applications. The Vacon 100 series is available in the power range 1.1…55 kW and voltage 380…480 V.

Rice. 5.

Specially designed converter self-protection and motor diagnostic systems ensure the operation of smoke removal fans in case of fire and thus save lives. Two PID controllers allow you to control both the motor itself and additional actuators through the signal input / output device. This eliminates the need for additional controllers (PLCs).

Characteristics and features:

• Graphic display;
• High efficiency film capacitors;
• The most compact frequency converter with IP54 protection class;
• Compliant with EN 61000-3-12 EMC class with low current harmonics;
• Built-in EMC filter;
• Built-in PLC;
• Built-in Ethernet and RS-485 protocol (Modbus);
• Real time counter function (possibility to change the parameters by the clock).

Vacon 10 Machinery - new series of frequency converters (Fig. 6). These are compact, simple and inexpensive vector frequency converters for operation in the low power range of 0.25…5.5 kW and voltages of 208…480 V.

Rice. 6.

This drive has a simple setup menu and a user-friendly interface, making commissioning possible even for non-professionals with little preparation. Vacon 10 Machinery are the most compact in the market of similar products. Despite its small size, the drive has a built-in EMC filter, is suitable for industrial applications and is able to solve the widest range of applications, offering maximum flexibility to suit the user's AC drive requirements. The design of the converter allows the user to install his own interface if necessary. Due to its small dimensions and low weight, the converter can be mounted on a DIN rail. Vacon 10 offers one of the customer's choice of communication systems, such as Modbus.

Characteristics and features:

• Smart menu navigation;
• DIN rail mounting or screw mounting;
• Possibility of installation of blocks of converters in a row;
• Application of the package for the development of application programs according to the individual requirements of the user;
• Possibility of programming and copying parameters in the absence of mains supply voltage;
• Built-in brake chopper;
• Built-in EMC filter;
• Fan with temperature sensor;
• Modular principle of using I/O boards;
• Built-in protocol RS-485 (Modbus);
• PID controller function;
• Ability to use various types of Fieldbus buses;
• Ideal solution for OEM.

Conclusion

Pumping units, automatic control systems in metalworking, electric drives in transport, elevator and hoisting equipment, security systems - Vacon's product range includes frequency converters for all of these applications.

Obtaining technical information, ordering samples, delivery - e-mail:

There are many myths around the concept of "lumen", therefore, in order to dispel some of them, consider the most frequently asked questions, such as: how many lumens are in an incandescent lamp, in an LED lamp, how many lumens does a 1W LED lamp contain, how to determine its luminous flux , and which LED lamps are similar to incandescent lamps.

To begin with, let's figure out what the concept of "lumen" means. A lumen is a unit of measure for the amount of light emitted from a light source, which can be an incandescent lamp, LED lamp, LED, or other lighting fixture.

To make it easier to conduct a comparative analysis, you can refer to the table, which shows the ratio of SP (lumens) to the power of the lighting device (W) for incandescent, fluorescent and LED lamps. Based on these data, it can be seen that LED lamps are 10 times more efficient than incandescent lamps, and 2 times more efficient than fluorescent lamps. In addition, unlike fluorescent lamps and incandescent lamps, the LED lamp, and therefore the LED, emits directional light, from which it can be concluded that the illumination from the LED lamp will be much higher. Therefore, using an LED street lamp as lighting, you can achieve much better illumination than when using other lamps.

As for the number of lumens in a 1W LED lamp.

For LEDs, the luminous flux ranges from 80 to 150 lm out of 1 watt. This is due to some differences in the current-voltage characteristics of LEDs and cooling systems. The luminous flux of experimental LEDs reaches 220 lm / W, but such LEDs are not found in mass production.

How can you determine the number of lumens in a lamp or light bulb.

Usually this information is indicated on the packaging or in the instructions for the product, but tabular data can also be used.
To independently determine lumens, you need a luxmeter that determines the level of illumination in each area of ​​\u200b\u200bthe room. Lux in this case is the quantitative ratio of lumens to the area of ​​illumination (1lux-1lumen per m2). With the intensity of light coming from an isotropic source equal to 1 candela, the total luminous flux is 4

In recent years, approaches to the organization of lighting in everyday life and public spaces have changed smoothly and painlessly. Now you will not surprise anyone with LED lamps.

Stores sell LED and fluorescent fixtures, but the customer keeps 'wattage' in mind as the main metric for light sources. Prudent manufacturers, of course, indicate the power on the packages of LED products, what this can mean. Is it worth focusing on power and how to determine the correspondence between the types of devices?

For more information on the level of illumination that an LED light source produces, see the emission indicated in lumens. What do lumens mean in LED lamps, we will understand in this article.

What is Lumen

The concept of lumen was established by the international measurement system in the middle of the twentieth century.

Lumens measure the amount of total light emitted by a source. The parameter is directly related to the concept of luxury, but there is a difference between them.

Expert opinion

Alexey Bartosh

It's important to understand! Lumen is the total amount of light that a source can emit in all directions. Lux is intended to indicate how much light hits a square meter of surface.

Therefore, if a lamp emitting 100 lm illuminates 1 m2 of the surface, then a flux equal to 100 lx will fall on it. If the same bulb shines in a room of 10 m2, then its illumination will be much lower. It is important to know that the calculations should take into account the entire luminous flux, in all directions.

In understanding this, one of the advantages of LED devices over incandescent lamps and fluorescent devices that glow in all directions is hidden. In diode lamps, the illumination angle approaches 120 or 180 degrees. With the help of built-in or external lenses, beams of any width are obtained.

Conclusion: the light flux is directed and used in the right direction, increasing its concentration.

Manufacturers actively use this feature in the development of LED lamps installed instead of halogen and xenon, d2s lamp, devices in car headlights. They are cheaper than xenon, load the electrics of cars less than halogen ones, not inferior in terms of illumination level.

Modern diodes are used to manufacture and replace 20 W lamps in position lamps and 55 W lamps in car headlights.

Parameters that determine the luminous flux and its calculation

For human perception, several indicators of luminous flux are important:

• The amount of total light emitted from a light source.
• Wavelength. It depends on how the eye perceives the brightness of light. Radiation in the middle, green part of the spectrum seems brighter than blue or red parts, with the same lamp power.
• Color temperature is measured in kelvins and must be indicated on packages and product data sheets. The picture shows the color temperature scale and the color of the emitted light.

Note! Warm colors are perceived by the human eye as less bright than cool colors. When buying "warm" lamps, make a small margin towards increasing power to create comfortable conditions in the room.

How many lumens in 1 W LED light bulb

Finding the right answer to a question is not easy. The fact is that manufacturers indicate the power and luminous flux for LEDs, not light bulbs. Real values ​​can only be measured with special instruments. Focus on averages.

In general, when consuming 1 W of power, LEDs emit 90–100 lm. Expensive samples are able to "give away" 130-140 lm from one watt.

Under laboratory conditions, LEDs were obtained that give out 220 Lm / W, but devices are not produced on an industrial scale due to their high cost.

Reduces the efficiency of the built-in LED power driver, reducing the ratio of luminous flux to power by 5-10%. It is important to consider this when choosing and buying light sources.

Convert Lumens to Watts

For users who do not want to study the characteristics of electrical appliances and carry out calculations, there are many resources on the Internet with built-in calculators. It is enough to substitute the data provided by the manufacturer (lumens) and select the type of lamp to get the required power indicator.

The method of calculating the illumination for rooms

The calculation of the required number of lighting fixtures uses a simple technique.

The calculations are carried out in two stages:

• Calculation of the required luminous flux intensity.
• Determination of the number of lamps capable of providing the desired illumination.

Formula for an approximate calculation of the level of illumination, Lm.

Luminous flux \u003d normative indicator of illumination in lux (given in the table) * room area in m2 * ceiling height factor.

For ceilings up to 2.7 m, a coefficient of 1 is applied, with a room height of 2.7 to 3 m - a coefficient of 1.2, from 3 to 3.5 m - 1.5.

Calculation example. In the nursery, the illumination standard is set at 200 Lux. Room area 12 m2 Height 3.1 m - apply a coefficient of 1.2.

Multiplying 200 * 12 * 1.2, you get the required luminous flux of 2880 Lm.

Knowing the light indicator, they choose devices capable of providing it. For a given room, one 25-30 W LED lamp, or three 10-Watt sources, is enough.

Expert opinion

Alexey Bartosh

Specialist in the repair, maintenance of electrical equipment and industrial electronics.

Important! For better illumination of the room, it is reasonable to use several lamps. This will evenly illuminate the room and get rid of the shadows.

Comparative characteristics of incandescent lamps and LED lamps

When comparing technical characteristics, all parameters speak in favor of diode devices.

Table 2. Comparison of the characteristics of LED and.

The regularly decreasing price of LED lamps, and the economic benefits from their use, make the devices popular among buyers.

How many lumens in LEDs in relation to other light sources

Table 3. Average luminous flux for different power consumption.

LED lamps from trusted manufacturers have undeniable advantages when used in everyday life and at work. They are durable, economical, pay for themselves quickly. The ability to choose any shade of glow will make your stay in the room comfortable and safe.