Rewiring a ballast. Help needed.

Radio

to

You are correct, However, I was not suggesting he rewire the sockets, only that with the limited info he provided we could be sure which 2 of the 4 contacts on the switch should be used for the starter.

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Vic Roberts
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Not sure if that ** is correct? Reason is I have some older non working older type fluorescents fixtures that I intend to update and respray that have those little aluminum can type starters that definitely worked on 115 AC. Some others have been converted to use the more modern type of ballast that does not require starter. In fact 50 years ago IIRC most/many f.fixtures used starters. They had/have a little neon and a resistor inside and yes you had to have the right kind of starter. The more modern ballast without the starter (not the even more modern electronic) is a lot more convenient. My reason for renovating older fixtures is that I've got a lifetime supply of good used and new ballasts! Also about 100 tubes (which are not that expensive anyway) at least 60% of which are good! And other useful bits. All that is needed is a bit of sanding a can of white spray paint and some time. And also yes the simple fluorescent on top of our cooking stove has that push and hold to start pre-heat type switch. The ballast for the fluorescent in that, AFIK, is just a choke (series inductor)? Have fun.

Sean I think I've got some starters somewhere I'll see if I can find them. But if it's standard four footer tube might be simpler but a bit more expensive to use a non-starter type ballast? All the spare ballasts I got are for the two 40/34 watt type tube fixtures. Email if you wish. Another Terry. Newfoundland Canada.

Installing a rapid start ballast is an option, though he'll have to fit a grounded power cord to ground the reflector for that approach, and the high humidity above the fish tank may prevent reliable starting. If I were doing this myself I'd pick up an electronic ballast for an F32T8 tube and retrofit it to T8, but then the old preheat start 40W T12's worked pretty well, the ballasts tend to run the tubes hotter than the newer RS stuff.

Sorry for the confusion. I said "power supply" thinking "power supply to the lamp" and was thinking that all preheat circuits use a simple series inductor (or resistor). I was unaware of preheat circuits that use a step-up transformer until this thread. (Still seems silly in view of rapid start ballasts.) With a step-up transformer, the voltage supplied to the lamp is well over 120 volts.

These must use a step-up transformer.

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115

They do, and they were quite common at one time. One other advantage they have is that they lack separate windings providing continuous power to the filaments in the tubes so the total power consumption is several watts lower.

The power savings is perhaps 1 watt per lamp and perhaps another watt in the ballast. The downside is much shorter lamp life. Rapid Start ballasts are by far the most common type of EM ballast use for 4-foot fluorescent lamps in the US.

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Rapid start circuits appear to date from the early 1950s. I have a GE publication dated 1/56 that describes them and calls them "new", but which devotes most of the fluorescent section to switch-start circuits. I remember seeing my first rapid start installation while in college about 1958 and being fascinated by the smooth starting of a room full of fixtures without the usual blinking and flickering that characterized switch-start lamps.

The F90T17 is still a listed lamp in the GE Catalog; however I was surprised to see the comment that they were used for streetlighting. The light output is low (about 5000 lumens) for its size. A 40 watt T17 was promoted for its low surface brightness and touted as one of the few fluorescent lamps that could be used in bare-tube installations with little glare.

For streetlighting, (in the US anyway) I thought that either 800 mA or 1500 mA T12 lamps were the only ones commonly used. The 4-foot

1500 mA T12 lamp is rated for about 6200 lumens.

Power Groove lamps are also still listed, but only in the 8-foot size. I've seen them also used for streetlighting, area lighting (gas stations) and billboard lighting. The grooved tube increases the phosphor surface area compared to smooth lamps and also increases the arc length for a given physical length. If you ever have a chance to examine a Power Groove lamp, feel the grooves near the center. Two of them are deeper than the others and they provide the "cold spot" that controls the amount of mercury in the arc. Power Groove lamps became fairly widely used in the 1960s (they appeared in 1958, I think) and were primarily promoted for high-bay industrial lighting.

I don't know if Gene Lemmers was the inventor. It's certainly likely. Gene continued working at Nela Park well into his 80s and commented to me once that he wanted to match the number of his patents to his age before retiring.

Terry McGowan

the

From what I've read, it's more like 3-6 watts per lamp, which if you're talking 500 lamps in a decent sized building can be somewhat significant. I haven't looked at what it does to lamp life, but instant start is the worst for that. It gets confusing too that most commercial or industrial types are specified at 10 hours per start, while residential lamps are rated for 3 hours per start. Lifespan drops dramatically with more frequent starting cycles.

[snip]

Terry - thanks for all the good information. I thought that Gene Lemmers was the inventor because I remember a lot of debates with Gene and Ed Hammer in the basement of Fluorescent Engineering, 437 I think, about why the Power Groove was more efficient than a normal 96" T17 lamp. Gene was a big proponent of the square cross section placing the phosphor closer to the discharge, as he like to say, but there was also the increased arc length as you point out.

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The power consumption in each electrode of a normal current rapid start lamps is 1 watt, or 2 watts per lamp. When you remove external electrode heat the arc voltage increases slightly and the net arc power increases by 1 watt for the same current. So, the net power reduction in the lamp is 1 watt. To get 3 to 6 watts per lamp + ballast the rapid start ballast would have to have an internal power loss of 2 to 5 watts per pair of lamp power windings, which is much too high to be reasonable.

I don't know where you get your data by the life of preheat lamps is far worse than instant start lamps. That is one reason why preheat had virtually disappeared from the US market in favor of rapid start and instant start. Preheat remains popular only for lamps that can be run directly from the power line with a simple series inductor or resistor. For 120-volt circuits this limits lamps to 2 feet long for T12 diameter. In those location of the world where the line voltage is

220 to 240 volts, preheat and a series inductor is used with 4-foot lamps.

Fluorescent lamps are rated on a 3 hour on, 20 minute off cycle. This includes what might be called commercial and residential types, though there is no formal distinction between the two. You may be confused by the fact that HID lamps are rated at 10 hours per start.

Most dramatically for preheat and instant start lamps. Less dramatically for rapid start. And for well designed programmed rapid start systems there can be virtually no loss of life. Osram sells a programmed rapid start CFL in Europe that is rated for 500,000 starts.

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quoting:

The starter/glow bottle for 4 foot, 40W tubes are usually labled "FS-4" .

It's generally not a good idea to use 34W tubes with preheat/switch start ballasts.

You have 4 wires in the "switch", correct? For the two wires that go to the each of the tube ends, put the starter in between those. You can just wrap the wires around the prongs of the starter, and insulate with black tape. The other two wires should be the "hot" side for the ballast. Just connect those together with a nut so that the light is "on" all the time, (but will be switched externally with a timer.)

One other question while on the topic of replacing ballasts and fluorescent lights.... I am remodelling an empty unit to make a bookstore and they currently have about fifteen to twenty 8 foot double tube lights throughout the store. (The store is about 2500 square feet.) I am considering replacing them all with about 50% more 4 foot units. (So about 22 - 30 units.) I am considering doing this mostly due to the high price of 8' tubes and ballasts. (In this part of Canada the 4' tubes go for about $1.40, while the

8' go for about $6-$7). Also the ballasts for the 8' bulbs costs about $30, whereas I can get a whole 4' unit for about that price. ($20 for a cheaper one that will probably break down in a few years, $30 - $35 for one that will hopefully last.) So there are actually two questions: 1) Will I retain a similar amount of light from replacing those units? (I know that their will be a small drop in light, but I just wanted to know how noticeable it would be? Or should I just double the number of 8' units and achieve near the same amount of light?) 2) Is it going to be cost effective over 10 -15 years to replace all these units? (Or am I wasting a lot of money trying to avoid spending $6 - $7 on the 8' tubes and $30 on a few new ballasts to replace the 3 or 4 that are burnt out?) Thanks for reading this long post, and for any answers or suggestions. Sean.

quoting:

$1.40 - is this for 34w, 40W, or T8 tubes? The local GESupply sells 34w CW tubes for about $1.30 currently, and about $2.50 for T8. 40W tubes are currently about $2.25 .

8' for $6 to $7 - Is this for 60W or 75W tubes?

Things to consider:

It all depends on 60W vs 75W tubes in the 8' lights now, vs T8 or 34W or 40W in the new lights.

Generally, old and most new magnetic 8' ballasts light 75w tubes to nearly full rated output. Same with old and most new magnetic ballasts for 4' 40w tubes.

34w tubes start out about 15 percent lower at full rated output, but they always never light more than 94 percent of their rated output on any ballast, even if that ballast was previously lighting a 40W tube at nearly full output. The same goes for 8' 60W vs 75W tubes on same ballast.

Typical T8 ballasts light T8 lamps to 88-92 percent of their rated output. You generally have to seek out ballasts that light T8 lamps to something near or over 100 percent of their rated output.

Generally, yes if you go with T8. (even better if you get ballasts that light the tubes to nearly or above their rated output.) If you ever consider saving energy with those 34W or 60W tubes - skip them. Go straight to T8. If you do decide to stay T12, just stay with 40W or 75W tubes. Don't use those 34w or 60W tubes, they are rather poor.

BTW, did you read my post about fixing your fish tank light?

SNIP

It sounds like there are some other questions that ought to be asked. Don't you want to know:

1. What kind of lighting should I have to sell the most books?
2. How can I get that lighting for the least cost over the next 10-15 years?

Given that you're thinking about cost effectiveness over the next 10-15 years, it isn't the tube cost or even the fixture cost that is going to impact you over time; it's the cost of energy (even if you have a 5 cent hydro rate). For every dollar you spend for lighting over those years, 90 cents or more will be for electricity and that includes the cost of lamps, fixtures and even the cost of money should you have to borrow to install the lighting.

At least go to a local electrical distributor and talk to the lighting specialist (call around until you find a distributor that has one). As a business, you should get at least a contractor price on lamps and fixtures. Or consider hiring a lighting designer to do the job. It's a rare designer who can't save your his/her fee on a job like this just by recommending the most cost effective solution.

Terry McGowan

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Here, Britain, 8' tubes are mostly 125w, with some being 100w. Presumably youve got 60w 8'. Basically the longer the tube, the better the efficiency.

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... you have all the 8' ballasts already, no extra spend needed. Re tubes, they last long enough for there to be no hurry, if you have anough that work now.

about $30,

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Thats the impression I get, but do the numbers. What does it cost you to fix he few 8'ers and provide tubes, what does it cost for 4'...

I'd look at just replacing a small number with 4', just as needed, but do it in one area to ensuer it looks decent, using the good 8' lamps in that area to repair or replace the dead ones elsewhere.

NT

Yes, longer is more efficient, but only if all else is equal. Modern

4-foot T8 lamps are more efficient than just about any 8-foot T12 lamp. The only 8-foot T12 lamps that may come close require rare earth phosphor coating which makes the lamp very expensive (due to its large size and low sales volume) and only about 0.5 lm/W more efficient than the comparable 4-foot T8 lamp (per data in the Philips catalog.) Plus, this data is taken at 50/60Hz, so the OP will get a boost of 10% ( 9 lm/W) in the lamp efficacy alone by switching to T8 and electronic ballast plus an additional boost of at least 10% from the more efficient electronic ballast.

As Terry has pointed out, the cost of electricity to operate the lamps over the life of the new fixtures is far higher than the cost of the lamps and ballasts and fixtures.

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Vic Roberts
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If you can find the ones with the electronic ballast (Shop Lights) they are TINY.

N