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Fluorescent Ballast Starting Voltage Booster/Capacitor

12/17/2014 2:38 PM

For the various species of ballasts (e. g., instant, rapid, electronic) that are in modern use, is (are) there any convenient, safe, inexpensive, etc. way(s) to retrofit a fixture with a capacitor or other means of boosting the starting voltage and, thereby, avoiding installing a new ballast and/or swapping out bulbs, the later still able to start satisfactorily in other fixtures with different (newer?) ballasts?

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#1

Re: Fluorescent Ballast Starting Voltage Booster/Capacitor

12/17/2014 3:25 PM

Yes but it isn't any cheaper than just buying a new and or correct ballast.

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#6
In reply to #1

Re: Fluorescent Ballast Starting Voltage Booster/Capacitor

12/18/2014 8:35 AM

The hose isn't going to work this time of the year where you are located. (I hope you shut off your exterior faucets in winter. ????)

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#7
In reply to #1

Re: Fluorescent Ballast Starting Voltage Booster/Capacitor

12/18/2014 11:51 AM

Thanks to all for comments...so far.

The hope is to not have to tear apart what averages as about one of five fixtures on which the newest and best bulbs still do not dependably start, rather install some form of voltage spiking item in the system (I would expect on the high side.) to extend the life of the ballast until there is irrefutable terminal failure of the ballast in, at least, its starting capacity, at which point the total tear down occurs and the voltage spiking device is relocated to another ailing, but not terminal ballast.

There must be a straight forward, inexpensive and safe way to do this with an off the shelf product. Where is our maven on this subject?

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#2

Re: Fluorescent Ballast Starting Voltage Booster/Capacitor

12/17/2014 3:53 PM

The ballast provides an important second function, to limit the current through the relatively low impedance arc once its been started. If you're looking to reduce the losses caused by the ballast, consider buying the latest LED flourescent tube replacements coming to market now.

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#3

Re: Fluorescent Ballast Starting Voltage Booster/Capacitor

12/17/2014 5:26 PM

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#4

Re: Fluorescent Ballast Starting Voltage Booster/Capacitor

12/17/2014 5:37 PM

Sure, just unscrew the blown fuse, put a penny in the socket and screw the fuse back in. Yer good as new, till the fire starts.

Do it right.

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#5

Re: Fluorescent Ballast Starting Voltage Booster/Capacitor

12/18/2014 5:41 AM

"to retrofit a fixture with a capacitor"

a capacitor will work as a current-limiting starter. But since it is also a hi-pass filter, all harmonics and spikes will cause nasty random flickering. Inductive starters were low-pass filters, so you got a smooth light output.

A capacitor is probably more expensive than a starter, so it's not worthwile. I just tried it because I was working in a capacitor factory.

brgds

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#8

Re: Fluorescent Ballast Starting Voltage Booster/Capacitor

12/18/2014 12:25 PM

Actually it is much simpler than adding electronic components. Frequently the problem is that the supply voltage is lower than the specification (rating) on the ballast. Since there is usually not much you can do about the supply voltage, there are some starting aids that I will mention.

First, I need to ask if your lamps are in a high humidity area. By high humidity, I mean frequently above 85% relative humidity. If so, a different treatment is required.

In most cases, the problem is due to lack of a decent ground plane. The specification typically requires the ground plane to be within 0.75 inch's from the surface of the bulb. But the term is a bit confusing because in starting the lamp any conductive material can be substituted as long as it runs the length of the lamp.

The most advanced ballast is the programmed start which is a hybrid between rapid start and instant start. But let's see if we can work with what you have.

The most effective starting aid is a strip of metal that is applied directly to the lamp but is short of coming into contact with the metal base. Most applications would be placed directly on the top of the lamp so as to not be noticeable. Even a decent piece of wire will work. No need to remove the insulation on the wire.

Here is how it works. When power is applied to the coils inside the lamp (any kind of ballast) the power will link to the wire through the glass and reconnect at the other end of the lamp. Initially the impedance is capacitive and on the order of millions of ohms. As the electricity starts to conduct into the starting aid, more and more gas inside the lamp becomes ionized and the plasma starts to glow at both ends of the bulb. In a very short time, the length of the plasma becomes longer from both ends until they meet in the middle. By that point, the net impedance has dropped to a couple of hundred ohms and since current takes the path of least resistance, the current through the glass becomes inconsequential.

If you use wire, it might be good to form a loop to pick up electrons from the vicinity of the coils at each end. You can see the coils if you place a light source behind the bulb near each end. My favorite starting aid is the metal tape that is used for making leaded glass artwork. It is cheap and already has adhesive on it.

This technique is well documented in the annals of lamp makers everywhere.

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#10
In reply to #8

Re: Fluorescent Ballast Starting Voltage Booster/Capacitor

12/19/2014 9:53 AM

Thanks. The kind of thorough and comprehensive counsel that I typically provide on matters of my experience. A trial roll of 3M 1120 aluminum foil tape with electrically conductive adhesive is on order. I will report the results of its use on several fixtures.

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#9

Re: Fluorescent Ballast Starting Voltage Booster/Capacitor

12/18/2014 2:30 PM

Be sure the power is off to the ballast before you attempt installing any "quick & dirty" fixes as the secondary voltage of most ballasts exceeds 400 volts and it is lethal.

I personally have known three people in my short lifetime that were electrocuted by making contact with the HV secondary of a ballast. Two were killed while replacing ballasts with the power on because operations did not want to affect the work areas and the other was in a scissor lift when he ruptured a lamp and made contact with the internal lamp heater element.

Ballasts contain a step-up transformer, capacitors, resistors, and in some cases IC circuitry for starting and lamp current control.

I would be very cautious in making any changes to lighting ballasts as you could well end up causing a fire.

A point to consider:

Starting in 2011 the lighting industry has been steadily decreasing the quantity of mercury in all lamps and bulbs.

The result is poor quality light color, lower lumen output, significantly decreased lamp and ballast life, and dramatic increases in lighting maintenance costs.

LED and Induction lighting pricing is dropping drastically almost daily and it will not be long before the cost of replacement with either of these two options becomes economically feasible.

Meantime you should be able to purchase electronic ballast for your fixture for less than $20 at the local "Big Box" store.

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#11
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Re: Fluorescent Ballast Starting Voltage Booster/Capacitor

12/19/2014 10:12 AM

The person said brain, I heard train and said I already had one.

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#12
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Re: Fluorescent Ballast Starting Voltage Booster/Capacitor

12/19/2014 10:40 AM

Good comments! One can never be too careful! I am a veteran of fluorescent lamp manufacturing including over 10 years in research and development. There are stories that I can not make public, but I say this, because it is fairly well known history. In terms of the mercury dose issue, by 1999 the big three lamp makers were all compliant with a test that was meant to measure the detrimental effect that a fluorescent lamp would have on the environment. They all passed by 1999. I had the honor of reducing the dose to a point where it was just enough for the lamp to work and no more. It was an adventure through hell to make that happen. Unfortunately, with over 4000 fluorescent lamp plants in China and other countries, the concern over the minimal mercury dose simply does not exist. Oil refineries pump out mercury into the atmosphere at a rate that is hundreds of times the exposure rate of all lamp manufacturers combined. So, all of this concern over fluorescent lamps was actually just environmental terrorism.

With respect to the potential for being shocked, you make a very good point about turning the fixture off. I've made the mistake of having my finger in contact with the pins on one end while plugging the other end into a live fixture. But the shock was not enough to be dangerous. Falling off the ladder (because of the not so nice surprise of participating as a conductor of electricity) was where the danger comes from. And when working from a scissor lift the fall can be deadly. But the current flow from a ballast is arguably not enough to kill anyone.

A starting aid on the outside of the bulb can provide a shock if the bulb is inserted into a live fixture. The current, however, is even lower because of the limitations of the capacitive coupling through the glass. Still, it can be a nasty surprise. So, I agree, "TURN THE POWER OFF FIRST" or ignore the shock. Don't fall off the ladder.

By the way, for a 4 foot lamp, the typical open circuit voltage for a Rapid Start ballast is about 300 VAC. For the same lamp as an Instant Start ballast produces an open circuit voltage of about 600 VAC. For an 8 foot lamp, the normal open circuit voltage is around 800 VAC. Any of those voltages has the potential of causing a spastic reaction, thereby throwing you off what ever platform you may be standing on. The voltage applied to a coil (requires both pins on one end) is only 6.3 VAC maximum. The problem is from the fixture side it is hard to tell which end is closest to neutral and which end is hot.

If you do install lamps into live fixtures, here is how you tell if the shock hazard exists. By that, I mean which socket is at hundreds of volts above neutral. As soon as one end of the bulb is inserted into the socket, it will either start to glow in the first six inches, or it won't. If it does not glow, you are making contact with the low potential of the device. It may not really be connected to neutral, but if there is a glow, it indicates that conditions are ripe for a shock.

With the newer electronic ballast, either end will glow upon initial contact. That means that you should go and turn off the power right now because the electronic ballast don't require either end to be near neutral or 0 Volts. Both ends could deliver a nasty surprise.

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#13
In reply to #12

Re: Fluorescent Ballast Starting Voltage Booster/Capacitor

01/04/2015 12:56 PM

The conductive metal tape would not stick to the bulb, requiring the use of a clear cellophane type tape around the bulb to hold it in place.

I found that cutting a narrow (4-5 mm wide) strip of common aluminum foil and taping it to the bulb with a 1 mm gap between the tape and the metal end seal housings at each end worked, but only if the foil strip was on the top of the bulb shaft and had several (about 3 intermediate tape bindings to the bulb shaft.

Still the start was a bit irregular and flickery, so I tried a spiral wrap around the bulb, occulting about 4-5 per cent of the light emitting surface of the bulb with the 6 to 9 spirals (1.6 to 1.7 m long foil strip) around the bulb, an arrangement which started instantly with very little sacrifice of illumination. Also, while replacing one bulb, I cracked the end cap seal and found that it was very easy to remove the foil and apply it to a new bulb.

None of the problematic start fixtures had to be replaced. All were brought to life with the foil wrap on existing (or one new) "four foot" fluorescent tubes. With the fixtures installed in open sided buildings (sheds, barns, etc.) exposed to ambient conditions, my remaining concern is how long the foil will last in the rather humid environment of the Florida swamp lands where temperatures will cross the freezing mark many nights every year.

Plaudits to NotUrOrdinaryJoe for his guidance. Long may CR4 live.

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#14

Re: Fluorescent Ballast Starting Voltage Booster/Capacitor

01/05/2015 12:50 PM

Bravo! The old T12 economy lamps had a tin oxide coating sprayed on the inside of the bulb before the powder coating was applied. Unfortunately when heat was applied to burn off the binder in the powder coating, it frequently burned off some of the tin oxide as well. It was a very tricky thing to control accurately.

The outside of the bulb had a solution with some kind of silicone applied to prevent water from coating the bulb. Made it slippery too but it was intended to cause the water condensation to bead up. A continuous film of water will prevent efforts to start the lamp. So, in Florida or other humid environments it can be a significant problem.

The exterior starting aid depends on capacitive coupling through the glass. The most critical part is right around the coils at each end. Your foil (about 1 to 2 inch squared)is good where it is near the internal coil (about 1 inch from the metallic base). After that, a small wire is sufficient to connect between each end. It does need to be tight against the glass for the most effective coupling. I liked to use magnetic wire to run from one end to the other but the insulation must be removed where it makes contact with the foil. For the magnetic wire, I just burn the insulation off where I want it to connect. Making it stick can be tricky. Clear fingernail polish works very nicely.

I also have one fixture that acts this way and on occasion, I will sweep my hand across the lamp from the glowing end toward the the other end. It usually starts by the time I pass the middle of the lamp.

Note that the current conducted through the lamp is likely to be on the order of microamps. So, with an ordinary bulb you won't feel it. But you can see the plasma come alive as you sweep across the lamp. With an external starting aid such as your foil, there can be a significant voltage build up while the lamp is trying to light. It is, after all, effectively an exposed plate of a capacitor. And, you might get a bit of a tingle as you bleed off the charge on it. Magnetic wire is very thin and won't block much light. Again, it has to make good contact with the foil.

If condensation is giving you problems, try some car wax. Water beads are OK but a continuous film is not. (Don't forget; Wipe on - let it dry - wipe off) If all of this continues to be a problem, an autotransformer can be used to boost the supply voltage sightly (10 - 15 volts) but a new ballast has almost as much likelihood to fix it too. Florida tends to have the most problems due to humidity.

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#15
In reply to #14

Re: Fluorescent Ballast Starting Voltage Booster/Capacitor

01/05/2015 8:49 PM

You have given me a lot with which to experiment.

I, too, have run my hand along a tube and watched the plasma waves bounce around as the fixture came to life. 20 years ago I sold my interest in a restaurant, leaving behind a huge roll of very heavy duty (20 micron thickness by 32 inches wide, I recall) aluminum foil. We used it as an oven liner to enhance cooking energy efficiency and to facilitate cleaning. One of my co-owner jobs (Mostly, I was a silent partner.)was to reline two ovens about once per month. The roll cost almost $100, but was enough to last for many years. If the place were still in business, I probably could have gone by to pick up a piece to make some very narrow foil strips by wrapping it on a piece of pvc pipe and scoring 2 mm wide strips on my lathe. Unfortunately, there is no place on Planet Earth where the restaurant business is more challenging than Florida; the property is now a pawn shop.

Thanks, again. My engineering is all things civil, structural, hydraulic, geotechnical and coastal.

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