Shed Lighting

[mkcl]

I'm also dubious about how a double fluoro can eliminate strobing. If you have three phase in your shed, you could have your lights on multiple circuits, each connected to a different phase. That would eliminate the problem (but would also involve paying your sparky extra ...)

If you only have single phase, an alternative approach would be to use an electronic ballast. All the ones I've seen rectify the supply and then use an inverter to power the tube. Since the inverter isn't phase-locked to the mains, all your lights should be out of phase with each other, eliminating strobing issues. Electronic ballasts are commonly available in two forms:
1) Replacements for the iron-core ballasts that come standard with fluoro battens.
2) Most (but not all) CFLs have a very low-tech electronic ballast in their base. To check for an electronic ballast, a simple test is to see how heavy the CFL is; an iron-core ballast is necessarily heavier than an electronic one. (If you're really keen, pull apart a dead CFL and inspect the ballast.)

I've gone the second route--I have a CFL mounted above my table saw. Given that CFLs are so cheap nowadays, I couldn't possibly justify the expense of option (1). Never had any strobing problems!


Michael.

[Iain]

Two half wave rectifiers can be phased as described.

[RETIRED]

I seem to have started a bit of furore with the statement that double fluoros are co phased.

When we had the lighting put in the workshop I was concerned about strobing particularly around the lathe and for medical reasons.

To have a post that can be up to 35' long appearing to run backwards is a little disconcerting to say the least. Our lathes can all be switched into reverse so as you can see this is not as silly as it seems. They don't cut real well and it is most embarrassing.

The medical reason is that I have Menieres Disease and strobing throws my balance out somewhat. There are some who say I am unbalanced most of the time.

I asked the electrician about it and I was repeating what he told me that twin fluoros are co phased and run a little out of sync. with each other and should not be a problem.

He was partially right. At certain speeds the lathe will "slow strobe" if that makes sense. I have found the best way to fix this problem is to raise or lower the speed of the lathe a bit or switch on more lights which seem to eliminate the problem.

David L: The statement that if it makes a noise it is running is quite true when you only work by yourself but if you have 2 or more working with other machinery running it is very hard to tell what is going and what is not sometimes.

[Dan]

No furore , just a new concept that on the surface doesn't seem to be fair dinkum, which is why we need to pull it apart to see how it works. Maybe we need those Myth Buster blokes to look into it.

Iain, where do half wave rectifiers come into it? :confused:

[Iain]

Just thinking out loud, but if you used two half wave rectifiers, one on each light with the anode to one and the cathode to the other you would have opposing pulses, would probably work on incandescant lighting.
Having said that, might as well go for a full wave and stop all the stuffing around, or use a bloody candle.

[jacko]

[QUOTE=Iain]Just thinking out loud, but if you used two half wave rectifiers, one on each light with the anode to one and the cathode to the other you would have opposing pulses, would probably work on incandescant lighting.
Yeh! And get half the lummens from each TL!!!

[jcani4]

I have a 6x5m shed and have 3 banks of double fluros - the normal ones - and found that they weren't bright enough.

hi there

i have a 6m x 9m m 2.7m shed with 6 double bright white fluros and it's heaps of light, it turns night into day thats for sure .. what i found that it's better to mount the lights on 1200mm x 800mm 16mm White board as it bounces the light down - well worth the extra $$

thanks

Justin

[mkcl]

Just thinking out loud, but if you used two half wave rectifiers, one on each light with the anode to one and the cathode to the other you would have opposing pulses, would probably work on incandescant lighting.
Having said that, might as well go for a full wave and stop all the stuffing around, or use a bloody candle.

Hmmm ... don't think this would work out. Several reasons I can think of:
1) As noted by jacko, you'll cut the duty cycle per tube by 50%.
2) The relatively long "off" period of each cycle would allow tube ionisation to drop noticeably, so you'd lose even more efficiency to increased resistance.
3) You'd kill the tube really quickly because all the filament sputtering would be concentrated on one end. (This is what causes the blackening of the tube ends.)
4) If one tube died, who knows what would happen to the current through the ballast, because half wave rectified current has a DC component. My guess is that the remaining tube would explode spectacularly due to excess current causing unchecked thermal expansion of the gas.

But the kicker is ... after all that, it wouldn't prevent strobing! Both tubes would still be phase-locked to the mains, and would provide very little light whenever the supply current drops to zero. You need some way to change the phase angle of the current, either by sourcing power from a different phase or by adding reactance to the circuit.

Michael.

PS. Personally, I prefer a CFL, but if you went with a candle, maybe you could cook your pancakes over it ...

[vsquizz]

I think the point may be lost. Flouros are good for gettingt rid of the dark spots in the shed and general lighting but they are a poor light to work under. There are far better lights for directly over the workbench or machines. Flouros are at their worst when there is a lot of reflective surfaces around.

Cheers

[rhizome]

Just thought I'd add my 2 cents worth here:

Fluro's seem to be fine for general lighting but for lighting the exact area you are working on, one of the best things I did was to set up one of the new 1W luxeon LED units (3W would be better) on a free standing adjustable arm arrangement. I can move it anywhere around the workshop and position the light exactly where I need it. The LED's offer a very white light, run only slightly warm and best of all you can run them off one of your rechargeable drill batteries for hours (no cords!)

I used the body of the hand held torch that came with my Makita drill set having ripped of the light head and re-wiring the internals. For the light I used a 1W Luxeon sealed unit made for garden lighting which can handle any voltage input between 12 and 28 volts AC or DC. There are many options available and a 3W unit would be much better. I think Hotbeam supply a very good unit as the higher watt versions need much better cooling. The only downside is the initial cost but considering the life span is around 100,000 hours you won't be replacing it in a hurry!

[simon c]

Sounds a good idea.

Can I just confirm that you are just using a single 1W LED. If I do my maths right, a 1W lamp running off of a 14.4V 2Ah cordless battery, would draw only 0.07A and would last for 28 hours. A 3W LED would last for approx 8 hours.

I might give it a go.

[rhizome]

I'm running a 12 volt 1.3Ah battery which seems to get around 3 to 4 hours out of it so your calculations would seem correct - I think the electronic converter inside the unit uses some power too. We use them for mountain biking off road at night and the 5 watt units are amazing but they run a bit hot to be standing still so the 3W unit would be a good choice.

I'll try and get a photo of my 'contraption' and post it in the near future...

[simon c]

If you are getting 3-4 hours out of a 12V 1.3Ah battery then it is probably drawing 3 or 4 Watts of power, so there is a reasonable amount used in the converter, but still pretty good. I think the 1W in LEDs refers to the light power rather than in an incandescent globe where it refers to the power drawn. Not sure though.

[soundman]

Any notion of half wave rectification doing anything for your strobing are a bit off.
the strobe frequency will 100Hz twice the mains frequency. By using the half wave rectification idea all you are doing is blocking each alternate half wave. you will still have 100Hz but at half the intensity.
As for the twin fluro idea the it sounds dodgy to me as well because both are connected to the same wave form and both wiil produce 100HZ.

The 3 phase idea I have heard is possible but is very expensixe & complex to wire and remember most of the fluro fittings and hardware will not be rated for 415V. this is a concern as ther will be 415V between adjacent tubes.

1 watt LEDs do draw 1 watt at about 4 volts but the current limiting circuit consume more power. example One 1 watt led and its drive circuit will draw about 3 watts from a 12 volt supply. A propperly driven 1 watt led is about as bright as a dolphin torch with a new battery & a kripton lamp.

I doubt if a properly maintained fluro would cause anybody "medical" problems. afterall the frame rate of TV os 50HZ as is some film projection.
If none of the above cause you a problem a fluro isnt likely to.
Get below 20Hz and I would expect problems.

Ther are some high frequency fluro drive circuits available that run at 30Khz or above. some of the 12v inverter units could be worth a look. In film & television there are some very funky high frequency drive units that produce very high quality, very high output from standard fluro tubes.

Fot the lathe you are probably better of with a good halogen work light.

cheers

[Optimark]

To soundman, I suffer from Thygeson's SPK, which is an eye disease. One of the side effects is photo phobia, which in this case means a fear of bright light.

What happens is that my eyes (especially my right one) are sensitive to bright lights that have a point source, like car headlights at night.

However. I also found that as the cycle of the disease goes through it's stages I am aware of the fluorescent lights causing me problems. The problems I won't go into, but, suffice to say, after installing tri-phosphorus tubes in my little factory, virtually all problems associated with my malady that were light induced at work, disappeared.

It didn't matter if normal tubes were new and operating at correct voltage and frequency, they caused problems sometimes. After switching tubes and starters I haven't had a problem in the last 8 years.

Interestingly they are initially more expensive but become cost effective because they use less power and last far longer. We did the sums on a spreadsheet after the first lot needed replacing and the overall was approximately 5% less total outlay for outright cost of tubes used as they lasted over twice the length of time of conventional. When you add the power consumed, it's a clear cut answer of which is best.

When my new garage is built this year I'll be installing tri-phosphorus tubes for overall lighting with spotlighting where required by tungsten or similar.

Mick.