Fluorescent tube lamps have long been popular in lighting rooms of any size. They work for a long time and do not burn out, which means they need to be serviced much less often. The main problem is not the burnout of the light bulb itself (burnout of the spiral and the phosphor), but the failure of the control gear. In this article, we will show you how to connect a fluorescent lamp without a choke and starter, as well as power it from a low-voltage DC source.
Classic scheme for switching on fluorescent lamps
Despite the technical progress and all the advantages of electronic ballasts (electronic ballasts), to this day, a switching circuit with a choke and a starter is often found. Let's remind how it looks:
A fluorescent lamp is a bulb that is structurally performed as a straight and twisted tube filled with mercury vapor. At its ends there are electrodes, for example, spirals or needles (for products with a cold cathode, which are used in monitor backlighting). The spirals have two leads to which power is supplied, and the walls of the flask are covered with layers of phosphor.
The principle of operation of a standard circuit for connecting a fluorescent tube with a choke and a starter is quite simple. At the first moment in time, when the starter contacts are cold and open, a glow discharge arises between them, it heats the contacts and they close, after which the current flows through the following circuit:
Phase-choke-spiral-starter-second spiral-zero.
At this moment, under the influence of the flowing current, the spirals are heated, while the contacts of the starter cool down. At a certain point in time, the contacts are bent from heating and the circuit is broken. Then, due to the energy accumulated in the choke, a voltage surge occurs and a glow discharge occurs in the lamp.
Such a light source cannot work directly from a 220V network, because for its operation it is necessary to create conditions with a "correct" power supply. Let's consider several options.
Powered by 220V without choke and starter
The fact is that starters periodically fail, and chokes burn out. All this is not cheap, so there are several schemes for connecting a lamp without these elements. You can see one of them in the picture below.
You can choose any diodes with a reverse voltage of at least 1000V and a current not less than the lamp consumes (from 0.5 A). Choose capacitors with the same voltage of 1000V and a capacity of 1-2 μF. Please note that in this wiring diagram, the lamp leads are shorted to each other. This means that the spirals do not participate in the ignition process and you can use the circuit to ignite the lamps where they burned out.
This scheme can be used to illuminate utility rooms and corridors. It can be used in the garage if you do not work on machines in it. Luminous efficiency may be lower than with a classic connection, and the luminous flux will flicker, although this is not always noticeable to the human eye. But such lighting can cause a stroboscopic effect - where rotating parts can appear stationary. Accordingly, this can lead to accidents.
Note: While experimenting, keep in mind that starting up fluorescent light sources during the cold season is always difficult.
The video below clearly shows how to run a fluorescent lamp using diodes and capacitors:
There is another scheme for connecting a fluorescent lamp without a starter and a choke. In this case, an incandescent light bulb is used as ballast.
Use a 40-60 W incandescent lamp as shown in the photo:
An alternative to the described methods is to use a board from energy-saving lamps. In fact, this is the same electronic ballast that is used with tubular analogs, but in a miniature format.
The video below clearly shows how to connect a fluorescent lamp through an energy-saving lamp board:
Power supply of lamps from 12V
But lovers of homemade products often ask themselves the question "How to light a fluorescent lamp from low voltage?", We found one of the answers to this question. To connect the fluorescent tube to a low-voltage DC source, such as a 12V battery, you need to assemble a step-up converter. The simplest option is a 1-transistor self-oscillating converter circuit. In addition to the transistor, we need to wind a three-winding transformer on a ferrite ring or rod.
This circuit can be used to connect fluorescent lamps to the vehicle's on-board network. It also does not need a throttle and a starter to work. Moreover, it will work even if its spirals are burned out. Perhaps you will like one of the variations of the considered scheme.
Starting a fluorescent lamp without a choke and a starter can be carried out according to several considered schemes. This is not an ideal solution, but rather a way out of the situation. A luminaire with such a connection diagram should not be used as the main lighting of workplaces, but it is acceptable for lighting rooms where a person does not spend much time - corridors, storerooms, etc.
You probably don't know:
A fluorescent lamp (LL) is a light source created by an electric discharge in an atmosphere of mercury vapor and an inert gas. This produces an invisible ultraviolet glow, which acts on the phosphor layer applied from the inside to the glass bulb. A typical circuit for switching on a fluorescent lamp is a ballast ballast (EMPRA).
Device and description of LL
The bulb of most lamps has always had a cylindrical shape, but now it can be in the form of a complex shape. At the ends, electrodes are mounted in it, structurally similar to some spirals of incandescent lamps, made of tungsten. They are soldered to external voltage pins.
The conductive gas medium inside the LL has a negative resistance. It manifests itself in a decrease in the voltage between opposite electrodes with an increase in the current, which must be limited. The circuit for switching on a fluorescent lamp contains a ballast (choke), the main purpose of which is to create a large voltage pulse for its ignition. In addition to it, the EMPRA includes a starter - a glow discharge lamp with two electrodes placed inside it in an inert gas environment. One of them is made of In the initial state, the electrodes are open.
The principle of LL operation
The starter circuit for switching on fluorescent lamps works as follows.
- Voltage is applied to the circuit, but at first the current does not flow through the LL due to the high resistance of the medium. The current flows along the spirals of the cathodes and heats them up. In addition, it also goes to the starter, for which the applied voltage is sufficient to generate a glow discharge inside.
- When the contacts of the starter are heated from the passing current, the bimetallic plate closes. After that, metal becomes the conductor, and the discharge stops.
- The bimetallic electrode cools down and opens the contact. In this case, the choke issues a high voltage pulse due to self-induction, and the LL is ignited.
- A current flows through the lamp, which then decreases by 2 times, since the voltage across the inductor drops. It is not enough to restart the starter, the contacts of which remain open when the LL burns.
The circuit for switching on two installed in one lamp, provides for the use of one common choke for them. They are connected in series, but each lamp has one parallel starter.
The disadvantage of the luminaire is that the second lamp turns off if one of them is out of order.
Important! Special switches must be used with fluorescent lamps. Low-cost devices have large starting currents, and the contacts can stick.
Throttle-free switching of fluorescent lamps: circuits
Despite the low cost, electromagnetic ballasts have disadvantages. They were the reason for the creation of electronic ignition circuits (ECG).
How LL starts with electronic ballasts
Throttle-free switching on of fluorescent lamps is performed through an electronic unit, in which a sequential change in voltage is formed when they are ignited.
Advantages of the electronic launch circuit:
- the ability to start with any time delay;
- no massive electromagnetic choke and starter needed;
- no buzzing and blinking of lamps;
- high luminous efficiency;
- lightness and compactness of the device;
- longer service life.
Modern electronic ballasts are compact and energy efficient. They are called drivers, placed in the base of a small-sized lamp. Throttle-free switching of fluorescent lamps allows the use of conventional standard holders.
The electronic ballast system converts the mains alternating voltage into high frequency. First, the LL electrodes are heated, and then a high voltage is applied. At high frequency, efficiency is increased and flicker is completely eliminated. The switching circuit can provide or with a smooth increase in brightness. In the first case, the service life of the electrodes is significantly reduced.
The increased voltage in the electronic circuit is created through the oscillatory circuit, leading to resonance and ignition of the lamp. Startup is much easier than in the classic EMC circuit. Then the voltage is also reduced to the desired discharge hold-up value.
The voltage is rectified after which it is smoothed by a parallel connected capacitor C1. After connecting to the network, the capacitor C 4 is immediately charged and the dinistor breaks through. The half-bridge generator is started on the TR 1 transformer and the T 1 and T 2 transistors. When a frequency of 45-50 kHz is reached, resonance is created using a series circuit C 2, C 3, L 1, connected to the electrodes, and the lamp is lit. This circuit also has a choke, but with very small dimensions, allowing it to be placed in the lamp base.
The electronic ballast has an automatic adjustment to the LL as the characteristics change. After a while, a worn out lamp requires an increase in voltage for ignition. In the electronic ballast circuit, it simply will not start, and the electronic ballast adjusts to changes in characteristics and thereby allows the device to be operated in favorable conditions.
The advantages of modern electronic ballasts are as follows:
- smooth inclusion;
- profitability of work;
- preservation of electrodes;
- elimination of flicker;
- performance at low temperatures;
- compactness;
- durability.
The disadvantages are higher cost and complex ignition circuitry.
Application of voltage multipliers
The method makes it possible to turn on the LL without electromagnetic ballast, but is mainly used to extend the life of the lamps. The switching circuit of burned-out fluorescent lamps allows them to work for some more time, if the power does not exceed 20-40 W. In this case, the filaments can be either intact or burnt out. In both cases, the leads of each filament must be short-circuited.
After rectification, the voltage doubles, and the lamp lights up instantly. Capacitors C 1, C 2 are selected for an operating voltage of 600 V. Their disadvantage is their large dimensions. Capacitors C 3, C 4 install mica capacitors for 1000 V.
LL is not intended for DC power supply. Over time, mercury accumulates near one of the electrodes, and the glow diminishes. To restore it, reverse the polarity by inverting the lamp. You can set the switch to keep it on.
Starterless circuit for switching on fluorescent lamps
A circuit with a starter requires a long warm-up of the lamp. In addition, it sometimes has to be changed. In this regard, there is another scheme with heating the electrodes through the secondary windings of the transformer, which also serves as a ballast.
When the fluorescent lamps are switched on without a starter, they must be marked RS (quick start). A luminaire with a starter start will not work here, since its electrodes take longer to heat up, and the spirals will quickly burn out.
How to turn on a burnt out lamp?
If the spirals are out of order, the LL can be ignited without a voltage multiplier using a conventional electronic ballast circuit. The switching circuit of a burned-out fluorescent lamp changes slightly compared to the usual one. To do this, a capacitor is connected in series to the starter, and the pins of the electrodes are short-circuited. After such a small alteration, the lamp will work for some more time.
Conclusion
The design and switching circuit of the fluorescent lamp is constantly being improved towards efficiency, reduction in size and increase in service life. It is important to operate it correctly, to understand all the variety of produced types and to know effective connection methods.
Dear visitors!!!
This method of connecting a fluorescent lamp should be familiar to everyone, in particular to professional electricians. With such a scheme for switching on a fluorescent lamp, there is one characteristic feature of the method of such a connection, which you will be familiar with. The information presented in this topic takes place in the training of students in the profession "Electrician of electrical networks and electrical equipment", which I am currently teaching.
How to turn on a fluorescent lamp - no choke
The figure shows two ways to connect fluorescent lamps:
schematic diagram of switching on a luminescent lamp with starter ignition (Fig. 1, a) and a diagram of switching on a fluorescent lamp without a choke (Fig. 1, b).
For both circuits for switching on fluorescent lamps, an increased voltage pulse that contributes to the formation of an arc discharge in the lamps (necessary for their ignition) is the LL choke and the EL2 incandescent lamp.
The second diagram (Fig. 1, b) shows a diagram of switching on a fluorescent lamp using an incandescent lamp (instead of a choke). In this circuit, there is a current-carrying wire, one end of which is connected to one of the leads of the electrodes of the fluorescent lamp. Instead of a live wire, a wide strip of foil can be used that has the same electrical connection as the wire. Accordingly, both the piece of wire itself and the strip of foil must be fixed at the ends of the bulb with metal clamps for the diameter of the bulb (fluorescent lamp).
That's all for now. Follow the rubric.
Ultraviolet lamp DRL "\u003e
Now chemistry based on photocatalysts is becoming widespread. Various adhesives, varnishes, photosensitive emulsions and other interesting achievements of the chemical industry. Unfortunately, industrial UV installations cost a lot of money.
What if you just want to try chemistry? will it fit or not? For this purpose, buying branded devices for N kilobucks is too curly ...
On the territory of the former USSR, they usually get out of the situation by extracting quartz tubes from DRL-type lamas, there is a whole line of llamas from DRL-125 to DRL-1000 with the help of them, you can get sufficiently powerful radiation, this radiation is usually enough for most occasional tasks. Type to harden glue or varnish once a month, or light up a photorezist.
How to get a tube from DRL lamps, how to do it safely, a lot of information has been written. I would like to touch upon another aspect, namely the launch of these lamps with minimal financial costs.
A special inductor with increased magnetic scattering is normally used for starting. But even he is not always available. it is heavy, then usually delivery to the regions costs a pretty penny. Choke 700W + shipping costs $ 100. That for an option to try, too, is never cheap.
A bit of theory:
The main problem with starting mercury lamps is the presence of an arc discharge. Moreover, a cold lamp and a hot one have fundamentally different resistance to the burning arc. Approximately from units of Ohms to tens of Ohms. Accordingly, for this, a choke is used that limits the current during start-up and operation of the lamp. It must be admitted that the choke is a rather archaic tool, and for expensive and powerful llamas used in UF-dryers (several kilowatts of power, and several thousand dollars per lamp), electronic arc stabilization units are used. These blocks allow for more accurate arc tolerance, thereby prolonging lamp life and reducing curing problems. Even for an archaic DRL, the manufacturer writes that the voltage spread is no more than 3%, otherwise the service life is reduced.
How to start a DRL Lamp without a throttle using improvised means?
The answer is simple, all you need to do is limit the current, in all operating modes, starting with warming up and ending with the operating mode. We will limit it with a resistor.
But since the resistor needs to be very powerful, we will use the heating devices available at hand (incandescent lamps, irons, kettles, hot water heaters, hand-held boilers, etc.) It sounds ridiculous, but it will work and fulfill its tasks.
The only drawback is the overconsumption of electricity, i.e. if we run a 400W DRL lamp on the ballast, about 250W will be released into heat. But I think for the task of trying ultraviolet light, or for occasional works, this is unimportant.
Why didn't anyone do that?
Why no one, there are DRB lamps in which this principle is used. Next to the quartz tube is the filament of an ordinary light bulb.
And writers on the Internet apparently did not teach physics at school. Well, of course, one more little nuance, you need a heating circuit, i.e. we heat the lamp with one resistor, and bring it to the operating mode with another. But I think many will cope with a switch and two wires :)
So the scheme:
So, for many, the correct schemes, this is a dark forest, I tried to depict in pictures. More close to life.
How it works?
1) Warm-up stage, the switch must be open !!! We turn on the lamp to the network. The incandescent lamp begins to glow brightly, the tube in the DRL lamp begins to flicker and slowly flare up. In 3-5 minutes the tube in the lamp will already start to shine brightly enough.
2) Second, we close the switch to the main ballast, the current will increase even more and after another 3 minutes the lamp will enter the operating mode.
Attention in total on the load of the lamp + irons, kettles, etc. will emit power comparable to the power of the lamp. The iron, for example, may turn off the built-in thermal relay, and the power of the DRL lamp will decrease.
For most, such a circuit will be very difficult, especially for those who do not have a resistance meter. For them I simplified the scheme even more:
The start is simple, we unscrew the lamps, leave only the required amount (1-2 pcs) to start the burner, and as it warms up, we begin to screw it in. For high-power DRL lamps, tubular halogen lamps can be used as a resistor.
Now the tricky part:
Probably, many have already understood that lamps and loads need to be selected somehow? Of course, if you take some kind of iron and connect it to the DRL-125 lamp, nothing will remain from the lamp, and you will get mercury contamination. By the way, the same will happen if you take a choke from the DRL-700 for the DRL-125 lamp. Those. the brain still needs to be included!
A few simple rules to save strength, nerves and health :)
1) It is impossible to focus on the nameplates of the devices, you need to measure the real resistance with an ohmmeter and do calculations. Or use it with a margin of safety, choosing a little less power than possible.
2) It is useless to measure the resistance of incandescent lamps, a cold coil has 10 times less resistance than a hot one. Incandescent lamps are the worst choice, you have to navigate by the inscription on the lamp. And in no case do not turn on the load from the incandescent lamps at once, screw them in 1-piece, reducing the current surges. Since I suspect that this will be the most popular way to turn on the DRL lamp without a choke. I shot a video for an example.
3) From general considerations, to start heating the DRL lamp, use a load not much more than its rated power. For example, DRL-400 for warming up, use 300-400 watts.
Table for different lamps:
| Lamp type | V-arcs | I-arcs | R-arcs | Ballast resistor | The inscription on the ballast \\ iron \\ lamp \\ ten | Heat at the ballast during work |
|---|---|---|---|---|---|---|
| DRL-125 | 125 in | 1 A | 125 Ohm | 80 ohm | 500 watts | 116 watts |
| DRL-250 | 130 in | 2 A | 68 Ohm | 48 ohm | 1000 watts | 170 watts |
| DRL-400 | 135 in | 3 A | 45 Ohm | 30 ohm | 1600 Wt | 250 watts |
| DRL-700 | 140 in | 5 A | 28 ohm | 17 ohm | 2850 Wt | 380 watts |
Comments to the table:
1 - the name of the lamp.
2 - operating voltage on a heated lamp.
3 - rated operating current of the lamp.
4 - the approximate working resistance of the lamp in a heated state.
5 - resistance of the ballast resistor for full power operation.
6 - the approximate power written on the nameplate of the device (heating elements, lamps, etc.) that will be used as a ballast resistor.
7 - power in watts, which will be allocated on the ballast resistor, or a device replacing it.
If it is difficult, or it seems to you that it will not work. I took off the video, as an example, a DRL-400 lamp I start it with three 300W lamps (they cost me 30 rubles each). The power on the DRL lamp turned out to be about 300W, the loss on incandescent lamps is 180W. As you can see, nothing is difficult.
Now fly in the ointment:
Unfortunately, it is not as easy to use burners from DRL lamps in commercial applications as it seems. The quartz tube in DRL lamps is made based on the calculations of work in an inert gas environment. In this regard, some technological simplifications have been introduced in production. This immediately affects the lifespan as soon as you break the external bulb. Although, of course, taking into account the low cost (Watt / ruble), it is not yet known that specialized lamps, or constantly changing emitters from DRLs, are more profitable. I will list the main mistakes in the design of any devices from DRL lamps:
1) Cooling the lamp. The lamp must be hot, only indirect cooling. Those. it is necessary to cool the reflector of the lamp and not the lamp itself. The ideal option is to put the emitter in a quartz tube and cool the outer quartz tube, not the emitter itself.
2) Using a lamp without reflectors, i.e. smashed the flask and screwed the lamp into the socket. The fact is that with this approach, the lamp does not warm up to operating temperatures, there is strong degradation and a decrease in the service life by a factor of thousands. The lamp should be placed in at least a U-shaped aluminum reflector to raise the temperature around the lamp. And at the same time focus the radiation.
3) Combat ozone. Powerful hood fans are installed, and if the flow goes through the lamp, then we get cooling. It is necessary to develop indirect ozone removal so that the air / ozone intake goes as far as possible from the lamp.
4) Clumsy when trimming the base. When obtaining the emitter, you must act as carefully as possible, otherwise microcracks in the places where the conductors are connected to the lamp will depressurize it in a dozen hours of burning.
A very common question about emission spectrum of a quartz bulb from DRL lamps... Because some chemical manufacturers write the sensitivity spectrum of their photoinitiators.
So the UV emitter of the DRL lamp is located at the midpoint between high and very high pressure; it has several resonances in the range from 312 to 579nm. The main resonance spectra look something like this.
I would also like to note that most of the available window panes will cut the lamp spectrum from the bottom to 400nm with an attenuation coefficient of 50-70%. Take this into account when designing exposure systems, curing, etc. Or look for chemically pure glasses with normalized transmission values.
I would like to remind you to use protective equipment when working with UF radiation, here are a couple of videos to watch.
First video. We draw your attention to the alien carrying the prints to the dryer with the cover removed, and this is how you have to protect yourself from UF radiation.
The second roller is a hand dryer for varnish. Unfortunately, it is not said that a hood is needed, ozone is not very useful ...
Well, it's not scary yet, then we move on. And what about the poor printers / silk-screen printers who decided to try modern UF paints. The prices from branded dryers are breathtaking, and if translated into rubles, they are simply nailed.
I think many have tried to dry the DRL with tubes, and nothing worked, well, except for some varieties of varnish.
In general, to be continued.
Read my reviews about printers and other equipment on mine and stay tuned.
