Throttle for fluorescent lamps: types of devices, purpose, circuit and feedback

Daylight lamps (LDS) are the first economical devices that appeared after traditional lamps with a filament. They relate to gas discharge devices, where an element limiting the power in the electrical circuit is necessarily required.

Throttle Assignment

The throttle for fluorescent lamps controls the voltage applied to the lamp electrodes. In addition, he has the following appointments:

• Protection from power surges;
• Heating cathodes;
• Creating a high voltage to start the lamp;
• Limiting the strength of the electric current after starting;
• Stabilization of the burning process of the lamp.

To save the throttle is connected to two lamps.

The principle of the electromagnetic ballast (EMPRA)

The first scheme for starting a fluorescent lamp, which was created and is still in use, includes the elements:

• throttle;
• starter;
• Two capacitors.

The scheme of a fluorescent lamp with a throttle is connected to a 220 V network. All the parts connected together are called electromagnetic ballast.

When power is applied, the circuit of the tungsten lamp spirals closes and the starter starts in the glow discharge mode. Through the lamp, the current does not pass. The threads are gradually warmed up. The starter contacts in the initial state are open. One of them is made of bimetallic. It bends when heated from a glow discharge and closes the circuit. In this case, the current increases by 2-3 times and the cathodes of the lamp warm up.

As soon as the starter contacts are closed, the discharge stops and the bimetallic plate begins to cool. As a result, the movable contact opens and the inductance of the throttle occurs as a significant voltage pulse. It is sufficient for it that electrons break through the gas medium between the electrodes and the lamp is lit. The rated current starts to flow through it, which then decreases by a factor of 2 due to the voltage drop across the throttle. The starter constantly remains in the off state (the contacts are open), while the LDS burns.

Thus, the ballast starts the lamp and then keeps it in the active state.

Advantages and disadvantages of EMPRA

Electromagnetic choke for fluorescent lamps is low price, simple design and high reliability.

In addition, there are drawbacks:

• Pulsating light, leading to eye fatigue;
• Up to 15% of electricity is lost;
• Noise at the time of launch and during operation;
• The lamp does not start properly at low temperatures;
• Large size and weight;
• Continuous start of the lamp.

Usually, the buzzing and flickering of the lamp occurs with unstable power. Ballasts produce with different levels of noise. To reduce it, you can choose the appropriate model.

Lamps and chokes are selected equal to each other in power, otherwise the lifetime of the lamp will be greatly reduced. Usually they are supplied in the kit, and the ballast is replaced with a device with the same parameters.

Fluorescent lamps complete with EmPra are inexpensive, and they do not need tuning.

Ballastnik is characterized by the consumption of reactive energy. To reduce losses parallel to the supply network, a capacitor is connected.

Electronic Ballast

All the imperfections of the electromagnetic choke had to be eliminated, and as a result of the research, an electronic choke was created for fluorescent lamps (electronic ballasts). The circuit is a single unit that starts and maintains the combustion process by forming a predetermined sequence of voltage changes. You can connect it using the instructions that accompany the model.

Throttle for fluorescent lamps of electronic type has the advantages:

• Possibility of instant start or with any delay;
• Lack of starter;
• No blinking;
• Increased light output;
• Compactness and lightness of the device;
• Optimal operating modes.

Electronic ballast is more expensive than an electromagnetic device due to a complex electronic circuit that includes filters, power factor correction, inverter and ballast. In some models, protection against the erroneous start of a lamp without lamps is established.

In user reviews it is said about the convenience of using electronic ballasts in energy-saving LDS, which are built directly into the base for conventional standard cartridges.

How to start a fluorescent lamp with electronic ballast?

When switched on from the electronic ballast, the electrodes are energized and warmed up. Then they receive a powerful impulse, which lights the lamp. It is formed by creating an oscillatory circuit entering resonance before discharge. In this way, the cathodes are heated well, all the mercury in the flask evaporates, so that the light starts easily. After the discharge occurs, the resonance of the oscillatory circuit stops immediately and the voltage drops to the working one.

The principle of operation of electronic ballast is similar to the option with an electromagnetic choke, since the lamp is triggered by a high voltage, which then decreases to a constant value and maintains a discharge in the lamp.

The current frequency reaches 20-60 kHz, due to which flicker is eliminated, and the efficiency becomes higher. In the reviews it is often suggested to replace electromagnetic chokes with electronic ones. It is important that they fit the power. The circuit can create an instantaneous start or with a gradual increase in brightness. Cold start is convenient, but the luminaire's service life is much less.

Fluorescent lamp without starter, throttle

LDS can be switched on without a bulky choke, using instead of it a simple incandescent lamp with a similar power. In this scheme, the starter is also not needed.

The connection is made via a rectifier, in which the voltage is doubled by means of capacitors and ignites the lamp without heating the cathodes. Consistently with the LDS through a phase wire, an incandescent lamp limiting the current is switched on. Condensers and rectifier bridge diodes should be selected with a margin of allowable voltage. When feeding the LDS through the rectifier, the flask on one side will soon begin to darken. In this case, the polarity of the supply must be changed.

Connecting a fluorescent lamp without a throttle, where the active load is used instead, gives a weak brightness.

If instead of the incandescent lamp to install the throttle, the lamp will glow significantly stronger.

Check of serviceability of a throttle

When LDS is not lit, the reason lies in the malfunction of the wiring, the lamp itself, the starter or throttle. Simple causes are identified by the tester. Before checking the choke of the fluorescent lamp with a multimeter, turn off the voltage and discharge the capacitors. Then the switch of the device is set to the continuity mode or to the minimum limit of the resistance measurement and determined:

• Coil winding integrity;
• Electrical resistance of the winding;
• Interturn closure;
• Break in the coil winding.

In the reviews it is suggested to check the choke by connecting it to the network through an incandescent lamp. When the interturn closure, it burns brightly, and serviceable - vpnnakala.

If a malfunction is detected, the throttle is easier to replace, since repairs can be more expensive.

Most often the starter is broken in the circuit. To verify its functionality, a known good is connected instead. If the lamp does not light up, then the reason is different.

The throttle is also checked using a serviceable lamp, connecting two wires to its base from it. If the lamp lights up bright, then the throttle is functional.

Conclusion

Throttle for fluorescent lamps is being improved in the direction of improving performance. Electronic devices begin to displace electromagnetic. At the same time, old versions of models continue to be used due to their simplicity and low price. It is necessary to understand all the variety of types, to properly operate them and connect them.