Electronic ballasts for fluorescent lamps: what it is, how it works, wiring diagrams for lamps with electronic ballasts

Vasily Borutsky
Checked by a specialist: Vasily Borutsky
Author: Victor Kitaev
Last update: April 2019

You are interested in why you need an electronic electronic ballast module for fluorescent lamps and how should it be connected? The correct installation of energy-saving fixtures will extend their service life many times, right? But you do not know how to connect the electronic ballasts and whether to do this?

We will tell you about the purpose of the electronic module and its connection - the article discusses the design features of this device, due to which the so-called starter voltage is formed, and the optimal operating mode of the lamps is also supported.

Schematic diagrams of connecting fluorescent bulbs using an electronic ballast, as well as video recommendations for the use of such devices are given. Which are an integral part of the scheme of gas discharge lamps, despite the fact that the design of such light sources can vary significantly.

Control Module Designs

Industrial and domestic structures fluorescent light bulbsare usually equipped with electronic ballasts. The abbreviation is read quite intelligibly - an electronic ballast.

Old-type electromagnetic device

Considering the design of this device from a series of electromagnetic classics, we can immediately note a clear drawback - the bulkiness of the module.

True, the designers have always sought to minimize the overall dimensions of the EMPR. To some extent, this was possible, judging by modern modifications already in the form of electronic ballasts.

Electromagnetic ballast
A set of functional elements of an electromagnetic ballast. Its components, as can be seen, are only two components - a throttle (so-called ballast) and a starter (discharge formation scheme)

The bulkiness of the electromagnetic structure is due to the introduction of a large-sized inductor into the circuit - an indispensable element designed to smooth out the mains voltage and act as a ballast.

In addition to the throttle, the EMPRA circuit includes starters (one or two). The obvious dependence of the quality of their work and the durability of the lamp, because a starter defect causes a false start, which means overcurrent on the filament.

Fluorescent lamp starter
It looks like one of the design options for the starter ballast electromagnetic module of fluorescent lamps. There are many other designs where there is a difference in size, body materials

Along with the unreliability of the starter start, fluorescent lamps suffer from the gating effect. It manifests itself in the form of flicker with a certain frequency close to 50 Hz.

Finally, the ballasts provide significant energy losses, that is, in general, reduces the efficiency of fluorescent lamps.

Design improvement to electronic ballasts

Since the 1990s, fluorescent lamp circuits have increasingly begun to complement the advanced design of the ballast module.

The basis of the upgraded module was semiconductor electronic elements. Accordingly, the dimensions of the device have decreased, and the quality of work is noted at a higher level.

Electronic ballast
The result of the modification of electromagnetic regulators is electronic semiconductor devices for starting and adjusting the glow of fluorescent lamps. From a technical point of view, they are characterized by higher performance

The introduction of semiconductor electronic ballasts led to the almost complete elimination of the shortcomings that were present in the circuits of obsolete devices.

Electronic modules show high-quality stable operation and increase the durability of fluorescent lamps.

Higher efficiency, smooth brightness control, increased power factor - all these are the primary indicators of the new electronic ballasts.

What does the device consist of?

The main components of the electronic module circuit are:

  • rectifier device;
  • electromagnetic radiation filter;
  • power factor corrector;
  • voltage smoothing filter;
  • inverter circuit;
  • throttle element.

Circuit construction provides one of two variations - bridge or half-bridge. Structures that use a bridge circuit, as a rule, support the work with high power lamps.

Relatively powerful fluorescent lamp
Approximately for such light devices (with a power of 100 watts or more), ballast modules designed according to a bridge circuit are designed. Which, in addition to supporting power, has a positive effect on the characteristics of the supply voltage

Meanwhile, mainly in the composition of fluorescent lamps, modules are built based on a half-bridge circuit.

Such devices are more common on the market compared to bridge devices, because for traditional applications, fixtures with a power of up to 50 watts are enough.

Features of the device

Conditionally, the functioning of electronics can be divided into three working stages. First of all, the function of preheating the filament is turned on, which is an important point in terms of the durability of gas light devices.

Especially necessary, this function is seen in low-temperature environments.

Electronic ballast inside
View of the working electronic board of one of the models of the ballast module on semiconductor elements. This small lightweight board completely replaces the functionality of the massive choke and adds a number of advanced features.

Then, the module circuit starts the function of generating a high-voltage impedance pulse - a voltage level of about 1.5 kV.

The presence of a voltage of this magnitude between the electrodes is inevitably accompanied by a breakdown of the gas medium of the fluorescent lamp balloon — ignition of the lamp.

Finally, the third stage of the module circuit is connected, the main function of which is to create a stabilized gas burning voltage inside the cylinder.

The voltage level in this case is relatively low, which ensures low energy consumption.

Schematic diagram of the ballast

As already noted, a frequently used design is an electronic ballast module assembled in a push-pull half-bridge circuit.

Electronic circuit diagram
Schematic diagram of a half-bridge device for starting and adjusting the parameters of fluorescent lamps. However, this is far from the only circuit solution used for the manufacture of electronic ballasts.

Such a scheme works in the following sequence:

  1. Mains voltage of 220V is supplied to the diode bridge and filter.
  2. A constant voltage of 300-310V is formed at the output of the filter.
  3. The inverter module ramps up the voltage frequency.
  4. From the inverter, the voltage passes to a balanced transformer.
  5. On the transformer due to the control keys, the necessary working potential for the fluorescent lamp is formed.

The control keys installed in the circuit of two sections of the primary and secondary windings regulate the required power.

Therefore, on the secondary winding, its potential is formed for each stage of the lamp operation. For example, when heating the filament one, in the current mode of operation the other.

Consider a schematic diagram of a half-bridge electronic ballast for lamps up to 30 watts. Here, the mains voltage is rectified by an assembly of four diodes.

The rectified voltage from the diode bridge hits the capacitor, where it is smoothed in amplitude, filtered from harmonics.

Instrument circuits for power up to 20 watts
The quality of the circuit is affected by the correct selection of electronic elements. Normal operation is characterized by the current parameter on the positive terminal of capacitor C1. The duration of the lamp ignition pulse is determined by the capacitor C4

Then, through the inverting part of the circuit, assembled on two key transistors (half-bridge), the voltage received from the network with a frequency of 50 Hz is converted into a potential with a higher frequency - from 20 kHz.

It is already fed to the terminals of the fluorescent lamp to ensure the operating mode.

Approximately the same principle applies bridge circuit. The only difference is that it uses not two inverters, but four key transistors. Accordingly, the scheme is somewhat complicated, additional elements are added.

Inverter bridge circuit
An inverter circuit assembly assembled according to a bridge circuit. Here, not two, but four key transistors are involved in the operation of the node. Moreover, semiconductor elements of the field structure are often preferred. In the diagram: VT1 ... VT4 - transistors; Tp - current transformer; Up, Un - converters

Meanwhile, it is the bridge assembly option that provides the connection of a large number of lamps (more than two) on one ballast. As a rule, devices assembled according to the bridge circuit are designed for load power from 100 W and higher.

Options for connecting fluorescent lamps

Depending on the circuit solutions used in the design of ballasts, the connection options can be very different.

If one model of the device supports, for example, connecting one lamp, another model can support the simultaneous operation of four lamps.

Turn on the electromagnetic ballast
The simplest version of the power supply of the lamp through an electromagnetic ballast: 1 - filament; 2 - starter; 3 - glass flask; 4 - throttle; L is the phase power line; N - zero line

The simplest connection is the option with an electromagnetic device, where the main elements of the circuit are only throttle and starter.

Here, from the network interface, the phase line is connected to one of the two terminals of the inductor, and the neutral wire is connected to one terminal of the fluorescent lamp.

The phase smoothed on the inductor is diverted from its second terminal and connected to the second (opposite) terminal.

The remaining two more lamp terminals are connected to the starter socket. This, in fact, is the whole circuit that was used everywhere before the appearance of electronic semiconductor electronic ballasts.

Connection of two lamps
Option to connect two fluorescent lamps through one inductor: 1 - filtering capacitor; 2 - a throttle equal in power to the power of two light devices; 3, 4 - lamps; 5.6 - launch starters; L is the phase power line; N - zero line

Based on the same schematic, a solution is implemented with the connection of two fluorescent lamps, one inductor and two starters. True, in this case, it is required to select a power reactor based on the total power of gas fixtures.

The throttle circuit variant can be modified in order to eliminate the gating defect. It quite often occurs precisely on lamps with electromagnetic electronic ballasts.

The refinement is accompanied by the addition of a circuit with a diode bridge, which is turned on after the throttle.

Connection to electronic modules

The options for connecting fluorescent lamps on electronic modules are slightly different. Each electronic ballast has input terminals for supplying mains voltage and output terminals for load.

Depending on the electronic ballast configuration, one or more lamps are connected. As a rule, on the device case of any power, designed to connect an appropriate number of fixtures, there is a circuit diagram for switching on.

Connection of two lamps on electronic ballasts
The procedure for connecting fluorescent lamps to the start-up and control device operating on semiconductor elements: 1 - interface for network and grounding; 2 - interface for fixtures; 3,4 - lamps; L is the phase power line; N is the zero line; 1 ... 6 - interface pins

The diagram above, for example, provides power for a maximum of two fluorescent lamps, since the model uses a double-lamp ballast model.

Two interfaces of the device are designed as follows: one for connecting the mains voltage and ground wire, the second for connecting lamps. This option is also from a series of simple solutions.

A similar device, but designed for operation with four lamps, is characterized by the presence of an increased number of terminals on the load connection interface. The network interface and the ground connection line remain unchanged.

Connection of four lamps on electronic ballasts
Wiring for the four-lamp version. An electronic semiconductor electronic ballast is also used as a trigger and control device. On the circuit 1 ... 10 - contacts of the interface of the starting and regulation

However, along with simple devices - one-, two-, four-lamp - there are ballast designs, the schematic of which involves the use of the function to adjust the glow of fluorescent lamps with.

These are the so-called controlled models of regulators. We recommend that you familiarize yourself with the principle of operation. power regulator lighting fixtures.

What is the difference between such devices from the devices already considered? In addition to the mains and the load, they are equipped with an interface for connecting a control voltage, the level of which is usually 1-10 volts DC.

Connection of a controlled lamp
Four-lamp configuration with the ability to continuously adjust the brightness of the glow: 1 - mode switch; 2 - contacts for supplying control voltage; 3 - grounding contact; 4, 5, 6, 7 - fluorescent lamps; L is the phase power line; N is the zero line; 1 ... 20 - contacts of the start-up and control device interface

Thus, the variety of configurations of electronic ballasts makes it possible to organize lighting systems at various levels. This refers not only to the level of power and area coverage, but also to the level of control.

Conclusions and useful video on the topic

The video material, based on the practice of an electrician, tells and shows which of the two devices should be recognized by the end user as better and more practical.

This story once again confirms that simple solutions look reliable and durable:

Meanwhile, electronic ballasts continue to improve. New models of such devices periodically appear on the market. Electronic designs are also not without drawbacks, but in comparison with electromagnetic options, they clearly show the best technical and operational qualities.

Do you understand the issues of the principle of operation and wiring diagrams of electronic ballasts and want to supplement the above material with personal observations? Or want to share useful recommendations on the nuances of repairing, replacing, or choosing a ballast? Please write your comments on this entry in the block below.

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