About Electronic Ballasts

I'd say it was just down to size and weight..I've had both types fail.

My vote is for simplicity...so it's the choke!

Jinxnao: Both work. Of course, the electronic versions are usually cheaper, lighter, cooler, and they don't develop that lousy humming noise which magnetic ones eventually do! Based on my experience, however, they are also not very robust; read below to see my experiences with using them in replacing regular light bulbs. One VERY big plus for the electronic ballast, however, is that it is small and light enough to allow it to be placed in the base of a small fluorescent-based replacement of the good-ol' incandescent light bulb! I doubt this could be done effectively with an inductive ballast.

Magnetic ballasts are, by their very nature, quite robust, especially since they are usually manufactured to specifications which are known from many, many years of experience. They are heavy, though, and they do give off quite a bit of heat as the light is operated over many hours; if the installation is not done to allow some ventilation for the heat to escape, the ballast could overheat and self-destruct. I've seen that a few times; it can be quite spectacular or, in other cases, it just makes a room smell very bad for quite a long time. I don't know for sure, but, I suspect the inductive ballast may be more expensive to make than the electronic version. I know of one case where a failed magnetic ballast caused a fire which destroyed several offices in a larger building. Given the way an electronic ballast is made, compared to a magnetic one, I suspect it would be much less likely to start a fire if it failed!

I purchased a number of fluorescent electronic-ballasted incandescent light bulb replacements for my home some months ago; several have failed already. Considering their costs - even at Wal-Mart, they cost at least ten times more than incandescent bulbs - and the rate at which they have been failing in my home, their amortized costs easily erase the savings I may realize in my power bill, especially if I were to replace them as they failed; I won't buy any more until I am convinced they are more robust than the ones I have tried (GE, Phillips, "no-name", Lights of America, I can't remember the rest...). If I could find a higher quality product, which did NOT fail so quickly (so far, none of the consumer brands I have tried has been superior to any others)...... I would probably realize the savings which the technology promises to yield, even if the lights themselves were twice as expensive. If anyone knows of such a brand of fluorescent, solid-state ballasted (perhaps Japanese-made?) light bulb replacements, with a superior track record, I'd appreciate knowing about it. I not only hate paying for the power used by incandescents, but, I also hate having to replace the ones in high and/or inconvenient places every few months! I had hoped the fluorescent replacements would eliminate this problem, however, they are at present so unreliable for my purposes, that they aren't worth the investment.

I don't pretend to know all about this; these are only my observations based on my experience.

Back to the subject: Why do I bring all this up?

Being a design engineer with no sense of priorities at all, I examined and tested the ballast circuits in the lights which have failed. To date, every failure has been due to the ballasts. In most cases, the power device fails. However, I've also seen two capacitor failures (these are easy to recognize since they make the most noise!). These are probably due to the use of inferior components; none of them had brand name markings on them (some had no markings at all!), so I don't know how to check their quality.

When I design products, I use a fairly conservative approach to component power and voltage ratings in circuits which could be exposed to transients and/or voltages and currents whose properties are either uncontrollable or unknown, such as we get over our power lines; even though I have used MOV's and many other devices and methods to account for this, my experience over the past 50+ years of electronics has been that nothing can replace good design practices, such as conservative ratings on critical components (when cost and other requirements allow, I suppose!) I suspect that the failures I am seeing may be due to some unusual spikes or other anomalies on my power lines; perhaps this is not very common in other areas? I also had one failure when I accidentally plugged one into an outlet controlled by an electronic dimmer. The lamp flickered in an odd way, then died. It also ruined the dimmer. I did not try to figure out why, as this was not a true "failure" of the ballast; it was my fault for doing something which is expressly warned against by the designers of the electronic-ballast fluorescent lights. I am not sure what caused the failure still....

I didn't intend to write this much; I just wrote what I was thinking as it occurred to me and I am too lazy to edit all this. Perhaps it will answer your questions?

Compact fluorescents usually fail because the starter fails.

Most of them can run for two or three years if they are just left on.

Let them burn fifteen minutes after you turn them on.

They will live longer.

The cheap ones don't start well at a low ambient temperature.

If you need dimmable compact fluorescents or low temperature operation,

contact a commercial lighting supplier. You will save in the long run.

The good ones last so long, you will clean your fixtures before you re-lamp.

Kosimov . You have done a fairly good explanation of the difference difference between the conventional chokes and electronic ballasts.I would like to share my experience with you. While I was working on electrical energy conservation project I landed with the idea of using electronic ballasts . During that time this product was not known in Indian market. Crompton a reputed Electrical manufacturers in India was developing this product with commercial name "Ensave electronic Ballast".With their development team I got a prototype of some specific model as per our specification for our factory and conducted various tests for their energy consumptions pattern and relative energy saving and their reliability under conditions of voltage and frequency fluctuations ,power interruptions and surge voltages. The final version was so good that we ordered replacement for one full shop floor lighting on experimental basis . The cost was almost Rs 500/- plus ,almost five times costlier than copper chokes.The energy saving between a reputed make conventional choke and electronic ballast was 22 watts .All tests carried out under similar conditions of voltage ,frequency and luminous intensity. All electronic components used for the lot was laboratory tested and the average life was almost 4000 hours . These results are under normal working conditions with a best quality product. But later we procured commercial quality electronic ballast of reputed make from regular market .The failure rate was much high and maintenance cost jumped up as labour charges for regular replacement was high and replacement of electronic ballast with copper choke was found not economical.The quality of electronic components used for ballasts were inferior and failure was mainly due to electrical surges and frequent power interruptions . Later we continued the trials with CFL (compact florescent Lamps)of 2 ,8, and 23 watts were found to be economical.In US where power quality is good and power interruptions are rare the life of CFL is found to be much longer.

BY USING A ELECTRONIC BALLAST WE CAN SAVE LARGE AMOUNT OF POWER ,EX IF WE USE A ELECTRONIC BALLAST INSTEAD OF ORDINARY BALLAST FOR 40 WATT LAMP,IT WILL CONSUME 30 WATT POWER BUT THE ORDINARY BALLAST CONSUME 50 WATT POWER,

ITS DISADVANTANGE MEANS INITIAL COST IS HIGH.

Well done MOHD12 - this the key answer.

The ballast in a discharge lighting fitting has two functions - 0ne to provide a high striking voltage to ignite the lamp and, Two - because the lamp cathodes have very little resistance - to limit the current consumed by the light fitting after ignition.

In a magnetic inductor the ballast is a high power consuming inductor. The high voltage pulse is produced only when the magnetic field collapses and not when the inductor is constantly powered up. In such cases the inductor has to be switched on and off rapidly to give repeated high voltage pulses. This is achieved by the thermal bi-metallic starter switch in the light fitting which makes and breaks the circuit until the steady state current conditions are reached after ignition.

With the lamp operating, the switch connects the inductor, which is no longer required for the high voltage pulses, in circuit with the lamp cathodes and the inductor impedance limits the current flow.

Being an almost pure inductor the power factor of the light fitting is very low and causes high reactive loads on circuits and switches, so a capacitor is required to increase the PF to an acceptable level.

The electronic ballast simply dispenses with the heavy magnetic inductor and starter switch and provides these functions with small electronic power components and as a result consumes much less power. Although the electronic ballast units can have some apparently large enclosures this is mainly to do with matching the fixing hole centres of previous magnetic ballast so they can be used a conversion replacement.

The electronic ballasts simply consist of a printed circuit board and the biggest component is the size of a 20mm cube. There is no requirement for a separate capacitor for PF correction.

Someone will no doubt correct me, but there is now a European directive to phase out all magnetic ballasts and the 35mm tubes - I think in 2008 with the 26mm tube to follow soon afterwards leaving fluorescent light technology in the form of the T5 - 16mm tube and electronic ballast.

There is one characteristic of electronic ballasts that hasn't been addressed--that is the phenomenon of "flicker-fusion." There are many people that can see the 50/60 Hz flicker from the magnetic ballast-driven lamps. When the ballasts and lamps age, the flicker is more prominent. The flicker causes headaches in sensitive people. The problem is gone with the high frequency electronic ballasts.

Dave Meador

To Mohd, Dave and Guest:

Thank you for your messages explaining the finer points of ballasts and fluorescent lights.

As soon as I read your messages, I knew that you were right, and that it was new information to me. I am an engineer but I do not design ballasts, so, I have no particular advantage over a dishwasher or anyone else with experience, when it comes to some of these things...

I am especially grateful for the information about flicker fusion and so forth. I've had six eye surgeries over the past few years, and my eyes have become VERY sensitive; I have thought I could see the flicker but I tried to convince myself it was my imagination. ANYTHING which strains the eye is a much bigger problem for me now than it was when I , and my eyes, were younger. Now, I will be able to shop for high frequency electronic ballasts to reduce the problem, which I have noticed since I installed rather "cheap" fluorescent lights in place of incandescent bulbs in my home. I have had to remove the fluorescents and put the old bulbs back for now, as I was having too much trouble with them; I was getting headaches and also, nausea, which my family believes was in my imagination (you know how it is with young men; they know so much. I did too, once, but the older I get, I realize, the less I really know, and the more I have to learn....)

In my reply, I did not address, nor did I think about, the power consumption difference between inductive and electronic ballasts. That is important. In fact, I have two inductive ballasted light fixtures in my garage, which are often on 24/7. I will take them down and put in electronic ballasted fixtures - as soon as I find a source for the higher frequency fixtures, that is!

I have never done much with sites such as this one; it has been interesting and informative, and quite enjoyable. I'll probably waste a lot more time doing this sort of thing now, than I usually do with everything else I find to distract me on the internet!

Thanks, again.

Larry

Some (cheap?) electronic ballasts seem to interfere with certain FM radios when they are within a few feet of each other.....

May I suggest that a small portable radio be taken with when shopping for such items and testing them working BEFORE purchase......! or make sure that you can return them if interference is found to be a problem....

Andy,

Do you know if the better ballasted lamps do NOT interfere with the radio, or perhaps, if they produce a distinctly different interference symptom than the cheap ones?

Thanks,

Larry

I must admit it was both a cheap radio and a cheap electronic ballast, better ones do not interfere with normal radio reception in my experience. It is some years ago that I had the problem!

Development has improved the products I am sure even more by now.....

I found out the hard way! But its a cheap and easy trick that I do not seem to be alone in using!!!

Make sure you take that radio with you.....

I've used a cheap AM radio tuned to a spot between stations. Great trick! Seems that dimmer switches are real noisy. Haven't noticed any RFI yet from my electronic fluorescent lamps. Maybe it is because of the USA FCC regulations on transmitted noise.

Dave Meador

Nobody has yet mentioned that some electronic ballasts produce harmonics which can boost neutral current beyond that expected in some situations.

Explain please.....