LED Bulbs for Fluorescent Fixtures

The operation of a discharge lamp is very different to a LED source. Among the types of discharge lamps, today we have the high pressure sodium vapour, metal halide and mercury vapor. To the latter, has assigned another name that everybody knows: the fluorescent bulb. It was put on the market for the first time in 1938 and, since then, its principle of operation has changed very little (to say nothing).

LED Bulbs for Fluorescent Fixtures

The majority of fluorescent bulbs that work currently have 3 basic elements: the lamp, ballast and starter. The scheme of operation is as follows:

When system is powered, pass current by the ballast, bulb tungsten filaments and electrodes of the choke. For every passing, the current causes a different effect according to Ledbulbbay.com, since in the ballast is beginning to generate electromagnetic flow and the bulb filaments become incandescent, which is beginning to cause the ionization of gases surrounding the filament, and on the other hand, the choke heats a gas which in turn heats a bi-metallic plate that is deformed by the heat effect. This deformation cause a circuit in parallel to which is operating is put into operation, which will cause a sudden change in the magnitude of current that flows through the ballast, generating the phenomenon than most we are interested in this article: an induction. The induction will generate a huge difference of potential between the ends of the bulb (close to the 1000V), causing the complete ionization of the gas bulb, which passed immediately to the plasma state, greatly facilitating the circulation of current. In fact, in that State, the resistance of mercury gas is negative.

The theme of the autoinduction in an inductive element such as ballast, is generated by sudden phenomena whenever there is a change in the magnitude of power, either an increase or a decrease. In other words, when we turn on and turn off the bulb, we have this phenomenon.

Perhaps on occasion have seen sequential fluorescent bulbs ignition method of a large surface (take a look at the gif that is a few lines below). This is because there is a concurrency factor, that what it does is limit the number of bulbs that can be lit at the same time in a facility without causing magneto-thermal protections jump ‘in the air’. For who at this point don’t know, will already be it sensing: the start and stop of fluorescent bulbs generate sudden electrical quantities during the time it takes the maneuver, such as overvoltage and overcurrent. The downside of all this, is that if it turns out that we have installed electronic elements in the same line and a certain proximity of the maneuvers, the odds of failure and premature deterioration increases considerably.

Now, if we talk about the combination with LED lighting products, there will be sources that run danger and others that do not. Higher power, with external drivers, with Earth, with a robust electronics and giving rise to sophisticated protection systems, such as for example an industrial campaign, priori there is no much problem; but on the other hand, if we are going to low-power LED sources, with small drivers that do not have space for filter, and much more simple electronic, the risk of premature failure and accused deterioration increase significantly (LED bulbs, for example). And on the side of more extreme, if we speak of drivers LED IC, i.e. those that are integrated into the plate or, in vulgar terms are known as ‘ LEDs without driver, would be much worse, because in most cases they lack protection systems beyond the modest systems carrying the tiny integrated.

There is also another problem, more patent in installations of public lighting there where luminaries or LEDs with HPS, mixing and it is the LED power factor lag is located in the capacitive display, and the HPS in the inductive, often generating a phenomenon of resonance that shoots the injection of harmonics in the network reducing the electrical quality of the entire municipality.

In short: good planning in which we can make provisions for substitution based on pictures, areas or lines, avoiding as much as possible mix LED with discharge lamps, favoring so LED work the hours that are promised at the time of sale and avoiding damage to the product by combining various technologies of lighting is important.