LED lamp: flicker and other problems. How to eliminate the flicker of LED lamps?

From time to time with LED lights, problems arise. The novelty of LED technology can complicate the diagnosis and correction of these difficulties. Below is a list of faults that may occur, with a description of the process of determining the cause of their occurrence and possible means of solving it. In particular, you will learn how to eliminate the flickering of LED lamps.

Problem: LED flicker. Possible cause No. 1: Incorrect voltage

LED lights require compliance with certain input parameters. Inadequate driver voltage can cause flashing or flickering of LED lamps.

To troubleshoot the problem, check the input voltage of the driver (for example, 120 V) and the luminaire (for example, 277 V). The problem may lie in their inconsistency. In this case, it is necessary to replace the driver or the luminaire itself in such a way that the voltage values coincide, or, if this is not possible, install a transformer that could provide the required parameters of the LED lamp.

Possible cause No. 2: incompatible dimmer

Flickering of LED lamps occurs when the luminaire is not designed for a particular dimmer load or if the driver is incompatible with its control circuit.

To diagnose this problem, turn off the brightness adjustment circuit. If the LED is functioning normally, then the dimmer or its load with it is incompatible. Please contact the luminaire manufacturer for clarification as to whether the driver is dimmable and, if so, which devices are compatible with it.

Possible cause No. 3: The nominal power of the presence or dimmer sensor

For correct functioning of these controls, a minimum nominal power is sometimes required. For example, the presence detector control unit may require a load of at least 20 W, and the LED consumes only 10 watts.

In order to eliminate the flickering of the LED lamps, additional devices must be added to the circuit, which will increase the load power to the required for normal operation of the device, or replace the control unit of the presence or dimmer sensor with another, with more moderate requirements for power consumption.

Possible cause No. 4: dimmer overload

The general problem of the system for controlling the glow of LED lamps is the inadvertent overload of the LED driver. It is designed for maximum load (measured in volts, amperes and watts), which should not be exceeded.

The number of lamps that can be installed on a single-phase dimmer, it would seem, is easy enough to calculate. For example, you need to know how many 15-watt LED lamps can be installed on a 600-watt dimmer. A quotient of 600 divided by 15 determines that you can control 40 lamps. Unfortunately, this result sometimes turns out to be wrong. In fact, the device of this power allows you to use only 6 LED lamps.

Although the total power of the LED is only 15 watts, the starting current and repeating half-period current surges load the dimmer much more. Thus, a 15-watt LED lamp for a dimming device will be equivalent to a 100 W incandescent lamp. In this case, if more than 6 light sources are used, the dimmer will be overloaded.

The average values of starting or half-period current surges are equivalent to the current consumed by a 100 W incandescent lamp, even if the load is less than 20 W!

The flicker of the LED bulbs can be remedied by following these steps:

• Refer to the technical characteristics of the luminaires for determining the equivalent load;
• Remove the dimmer from the power line of the lamp and find out if this solves the problem;
• Replace the dimmer switch to a device with a higher maximum load;
• Divide the chain into several loads.

Possible cause No. 5: insufficient load of the dimmer

Some dimmers do not function correctly when the load is too low. For their normal operation, it may take some minimum amount of luminaires, based on 25-40 W, necessary for a conventional dimmer. One incandescent lamp easily meets the minimum load requirements. But LED-lighting fixtures may need 4 times more.

To eliminate the flicker of the LED lamps, caused by a small load dimmer, you should:

• Refer to its technical specifications for determining the minimum load;
• Remove the dimmer from the lighting circuit to make sure the problem is solved;
• Replace the dimmer with a device with a lower minimum load.

Problem: the flickering of the switched off LED bulbs. Possible cause No. 1: Guidance from nearby wiring

The flickering of the LED lamps in the off state occurs when the wiring through which the current flows is parallel is laid. In the disconnected conductor there is a voltage, which is the cause of the lamp flashing.

Solve the problem by the following methods:

• Parallel to the luminaire, connect a shunt capacitor with a capacitance of 0.01-1 μF, a voltage of at least 400 V, or a resistor with a power of 0.5-2 W and a resistance of 100 kΩ-1.5 MΩ, through which the supply current of the illumination will flow;
• Parallel to the LED light switch on the incandescent lamp.

Possible cause No. 2: Backlight current

When a switch with a backlight and an LED lamp are used, the flickering occurs even when the lamp is off. The backlight consumes a current that charges the capacitor of the electronic circuitry of the luminaire to a level sufficient for a flash.

How to remove the flicker of LED lamps in this case? You must use one of the following methods:

• Parallel to the luminaire, connect a shunt capacitor with a capacitance of 0.01-1 μF, a voltage of at least 400 V or a resistor with a power of 0.5-2 W and a resistance of 100 kΩ-1.5 MΩ, through which the supply current of the illumination will flow;
• Parallel to the LED light switch on the incandescent lamp;
• Replace the backlit switch with a back-lit switch with backlight, connecting it so that, in the switched off state, both contacts of the luminaire are closed to the neutral wire;
• Replace the switch with backlight for normal;
• Power backlight to carry through a separate neutral wire;
• Remove the light of the switch.

Problem: The LED lamp does not light up. Possible cause No. 1: Wrong posting

In this case, there may be a bad connection between the LED and the driver, the network and the luminaire. You should check all electrical connections between the LED and the driver and between the line and the driver and make sure the voltage matches. Make sure that all circuit breakers are turned on and all connections are made correctly.

It is necessary to check all the wires connected to the luminaire, including phase, zero, ground, dimming circuits and emergency lighting wiring.

Possible cause No. 2: LED damage

LEDs can be damaged by excessive vibration, humidity and chemical or aerosol contamination.

In this case, make sure that the lamp is defective by installing it in a known good lamp when the power is off.

Climatic and other equipment can create a vibration that can affect the LED if it is in close proximity to its housing. It is necessary to verify the presence of such an effect and to eliminate or reduce the vibration or to increase the distance between its source and the housing of the luminaire.

Damage caused by liquids, contamination by chemicals or aerosols, can cause the LED to malfunction or malfunction. Their sources should be eliminated before any attempt is made to repair the malfunction.

Possible cause No. 3: LED damage for other reasons

Like any other light source, the LED lamp can fail due to physical impact, including accidental drop.

In addition, the LED can be damaged by voltage surges that occur when it is connected while the power is on.

• In this case, you should make sure that the lamp is defective by installing it in a known good condition when the power is off.
• The luminaire must be checked for visible damage to the LEDs.
• When connecting the LED to the driver, make sure that the power is off.

Possible cause No. 4: driver damage

The LED driver has certain input parameters. Failure to supply the wrong voltage may result in damage. Incorrect connection and poor electrical connections can also damage the LED.

To solve the problem, check the driver input voltage (for example, 120 V), and then in the luminaire (for example, 277 V). There may be a mismatch.

It is necessary to try to install a faulty LED instead of working, without forgetting to turn off the power. If it does not light up, then the reason lies in the LED-lamp.

You should check all the wires connected to the driver, including phase and zero, dimming circuits, emergency lighting , etc., and eliminate the identified faults. If this does not work, then the driver is probably damaged. In this regard, you need to contact the manufacturer.

Problem: LEDs turn yellow or discolor. Possible cause No. 1: incompatibility between the LED and its power supply

The base of the LED lamp may be incompatible with the driver. For example, a 6-inch 10-watt LED is installed in a 6-inch 15-watt cartridge.

Most LEDs of different power can match the same housing size. However, the LED may be incompatible with the enclosure driver, even if they fit together. It is necessary to consult the seller or the manufacturer on the question whether a particular LED is suitable for a particular enclosure. Otherwise, you should order new LEDs of the appropriate power.

Possible cause No. 2: high ambient temperature

A high ambient temperature can occur. Heat is the enemy of LED technology and can significantly shorten the life of the lamp. Weather or climate can play a significant role in hot, arid, desert areas and localities with a combination of heat and humidity.

To solve the problem, it is necessary to check the temperature near the lamp body, below and above the suspended ceiling. If the ambient temperature constantly exceeds 50 ° C, the LED will be damaged and will not work as expected. You should correct this problem by reducing the air temperature or moving the device. However, this does not return the LED to its previous state. It is necessary to contact the manufacturer to replace the LED light.

Possible cause No. 3: end of life

At the end of the life of the luminaire, the LEDs can change the luminescence temperature, the color rendering index and the luminous efficiency. This is a sign that the LED lamp may need to be replaced. In this case, you need to contact the manufacturer.

Problem: low flicker frequency of LED lamps

Blinking of light can cause eye fatigue and impair performance. It is characterized by the coefficient and frequency.

The flicker factor of LED lamps is the ratio of the difference between the maximum and minimum illumination to their sum. It can range from 0% for luminaires powered by a constant current source, up to 100%. The value of the coefficient for incandescent lamps is 6-17%. According to the standards, it should not exceed 20%.

The flicker frequency of the LED lamps depends on the driver and is equal to 100 Hz for conventional ballast. The optimum value of this parameter is above 300 Hz.

How do I check the flicker of an LED lamp? This can be done in several ways:

• With the help of a smartphone camera with the flicker-free option turned on;
• Photographed the light source with a smartphone camera - the presence of darkened bands will indicate the presence of pulsation;
• Using a photodiode connected to a PC, a multimeter or headphones;
• Using a luxmeter that allows such measurements;
• Observing the stroboscopic effect of a fast moving object (for example, ruler, pencil or yule).

Eliminate LED flicker, not associated with improper operation of the luminaire, can be done in such ways:

• Use a source of really constant, rather than pulsating current;
• To replace a lamp with a high flicker factor for an LED lamp that meets the standards.