Wiring diagram of fluorescent lamp ballast and its working principle introduction

Fluorescent lamps are the daily lighting tools for our daily working life, which bring light and convenience to our life. Almost no one does not know fluorescent lamps, but there are a lot of people do not know and fluorescent lamps supporting a product - ballast. Now the use of basically are inductive ballasts. I know, fluorescent lamp electronic ballasts and fluorescent lamps must be used in conjunction, it can ensure that fluorescent lamps can be ignited normally, and to achieve the performance indicators to start working. Today, you and I came to understand the principle of ballast work and wiring diagram.

Most of the gas discharge lamps are made of arc discharge characteristics,with the negative characteristics of the voltage decreases with the increase in current (also known as negative resistance characteristics), it is not possible to establish a stable operating point. In order to stabilize the discharge and limit the lamp operating current, a ballast must be set in the gas discharge light source circuit. Ballast has become an important additional device in the gas discharge light source circuit. The use of semiconductor electronic components, DC or low-frequency AC voltage into high-frequency AC voltage, drive low voltage gas discharge lamps, tungsten halogen lamps and other light sources work electronic control devices. The most widely used is the electronic ballast for fluorescent lamps.

Fluorescent lamp inductive ballast working principle and wiring diagram

(1) when sending out the AC power, because the fluorescent lamp belongs to the cold lamp, the lamp resistance is infinite, the large current flows to the impedance of the starter, so the neon lamp will be bright for a moment with the capacitance to form a collapse, at this time, current flows through the tungsten filament at both ends of the lamp, the tungsten filament is therefore heated, this period of time for the 0 to A time.

(2) when the time in A that is, the supply voltage is zero volts , because the fluorescent lamp at this time has been a hot lamp, so that the resistance in the lamp is quite small, at this time the starter part of the collapse stops, followed by time A to time B fluorescent lamps lit successfully, and time B after the fluorescent lamps on both sides of the voltage drop of about only about 122 volts or so (20W fluorescent lamps), make the The starter no longer crashes, and from then on the fluorescent lamps work normally to maintain a certain brightness until the power off fluorescent lamps out.

(3) At time A to time B, the inductive ballast (inductor) ends of the induced voltage of 220 volts, plus the power supply of 220 volts, its fluorescent lamps at both ends of the total voltage drop of 440 volts, so the fluorescent lamps need a large voltage to start.

(4) After time B, the inductive ballast (inductor) plays the important role of constant current, so the fluorescent lamps always maintain a fixed brightness.

Principle of operation:

When the switch is switched on, the supply voltage is immediately added to the poles of the glow starter through the ballast and the lamp filament.220 volts immediately ionizes the inert gas of the glow starter, producing a glow discharge.

The heat of this process makes the bimetal thermal expansion, because the degree of expansion of static and dynamic contacts is different, the U-shaped dynamic contacts expansion and elongation, and static contacts contact and connect the circuit, so the ballast poles contact. Current through the ballast, the starter contacts and both ends of the filament constitute a path. At this time, due to the two poles of the starter closed, the voltage between the two poles is zero, the starter in the neon gas to stop the conductive, glow discharge disappears, resulting in a drop in the temperature inside the tube, the U-shaped movable contact plate cooling contraction, the two contact plate separation, the circuit is automatically disconnected.

In the instant the poles are disconnected, the circuit current is suddenly cut off, the ballast produces a large self-inductance potential, and the power supply voltage superimposed on the tube ends. When the filament is heated, a large number of electrons are emitted, and under the action of high voltage at both ends of the tube, they move with great speed from the low-potential end to the high-potential end. In the process of accelerated movement, collision of argon molecules in the tube, so that the rapid ionization. Argon ionization heat, heat to produce mercury vapor, and then mercury vapor is ionized, and emit strong ultraviolet light.

In the ultraviolet excitation, the phosphor in the wall of the tube emits nearly white visible light. After the fluorescent lamps are normally illuminated. As the alternating current continuously passes through the ballast coil, the coil produces self-induced electromotive force, the self-induced electromotive force hinders the change of current in the coil, then the ballast plays the role of voltage reduction and current limitation, so that the current is stabilized in the rated current range of the lamp, and the voltage of the two ends of the lamp is also stabilized in the rated operating voltage range.

There are many kinds of wiring diagrams for fluorescent lamp ballasts, the main difference lies in the structure of the circuit itself and the structure of the house. The ballast should meet various international standards such as the rated current voltage and the range of voltage variations. Sometimes the home of the fluorescent lamp suddenly does not light up, it may be a ballast failure, at this time you should find a professional electrician to come over to the home to repair. I suggest, if you want to personally repair electrical appliances, you can first turn off the power, please pay attention to their own safety.

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