How many CFLs does it take to ....

**Wait for decent LEDs to fall in price. They eclipse CFLs efficiency-wise, are easy to use and are very dimmable. Give it a couple of years.

--
Trevor Wilson
www.rageaudio.com.au

"Phil Allison"

Hi to all,

just picked up a "dimmable" CFL from K-Mart, a Mirabella brand 15 watt spiral type - price was reduced from $20 to $8, which is more like their true value.

** Oh dear - the thing has died already.

Got about 10 hours out of it before one end of the spiral has gone black = blown heater.

Back it goes .......

..... Phil

Mirabella s**te. Had so many problems with this brand it isn't funny. False economy buying the crap. Costs more to take back for a refund and not worth the hassle. Best just avoided in the first place.

On Dec 19, 6:57=A0pm, "Alan Rutlidge" False economy buying the crap. =A0Costs more to take back for a refund an= d not

Agree. Same with standard fluorescent tubes. NEC are a better choice.

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I wouldnt want to try it. I think the dimmer wouldnt survive it. Happening repeatedly like that, I wouldnt want to try 2-3 even.

While on a similar subject:

Was at Haymans yesterday, and was talking about CFL and LED lighting. The sales manager at our local branch is an experienced electrician (but not expert on "electronics") and said that there had been problems with people putting more than 4-5 + CFL's (wattage unknown) in light sockets the same light switch, then having nuisance tripping of the circuit breaker for the light circuit, at switch on, and this was causing headaches for electricians being called in to "find the fault", which, unsurprisingly, they couldn't.

This had increased recently with the Christmas and party season with people using CFL's instead of bulbs in those "festoon" party light strings, and turning on heaps of them at once. Some were worried that the "CFL's must be faulty / dangerous / using more power than incandescent" as they "never had this problem with the old bulbs".

We will surely see more of these problems when inevitably people try to flash strings of CFL 's, (with festoon light setups, in commercial situations) - especially when incandescents become no longer available and CFL's are used. Doing this with a "musicolour" or light chaser - you would likely destroy the output devices.

There has already been a post about suitable substitute bulbs (if incandescents are gone) for this kit on this forum this week.

There had also been problems with plastics in non-UV stabilised light fittings falling apart. In one case the plastic nut holding glass front of an cheap oyster fitting had deteriorated and the glass bowl had fallen onto the coffee table. From the description, it sounded more like a circular fluro unit rather than a CFL - but both would emit UV. This could possibly start happening if CFL;s are put into non UV stable fittings originally meant for bulbs.

For that matter, are the standard white batten holders, used by the millions in aussie homes for the past 30+ years made of UV stable plastics ?

Definitely not! Ditto for fluorescent tube lamps. I work in a power station where we use hundreds of fluorescent lights for general lighting and the tombstones, starters and starter holders crumble into dust at the slightest touch. Also the wiring becomes brittle and breaks off with any movement. Those things are death-traps. It's easier and cheaper to replace the whole light assembly than to try and fix them.

"kreed"

While on a similar subject:

Was at Haymans yesterday, and was talking about CFL and LED lighting. The sales manager at our local branch is an experienced electrician (but not expert on "electronics") and said that there had been problems with people putting more than 4-5 + CFL's (wattage unknown) in light sockets the same light switch, then having nuisance tripping of the circuit breaker for the light circuit, at switch on, and this was causing headaches for electricians being called in to "find the fault", which, unsurprisingly, they couldn't.

** I predicted thus would be the case a long time ago, in discussions I had with Rod Elliot of ESP.

Typical 13 to 23 watt CFLs have a 4.7 to 22 ohm resistor in series with a

10uF to 22uF uF electro immediately after the bridge rectifer. When switched on at the AC voltage peak, this generates a spike of current of about 20 to 30 amps per lamp that last about 0.5 mS or so.

With 5 or 6 in parallel, the current spike builds up to well over 100 amps and may trip an 8 amp "thermal magnetic" breaker. The magnetic function of such breakers breaker is damn near instantaneous when the current exceeds 10 times the nominal rated value.

This had increased recently with the Christmas and party season with people using CFL's instead of bulbs in those "festoon" party light strings, and turning on heaps of them at once. Some were worried that the "CFL's must be faulty / dangerous / using more power than incandescent" as they "never had this problem with the old bulbs".

** With normal incandescent bulbs of no more than say 100 watts each - it is possible to load and reliably switch a single lighting circuit right up to the nominal 2kW limit.

With CFLs, the limit falls to around 100 to 200 watts - at most.

We will surely see more of these problems when inevitably people try to flash strings of CFL 's, (with festoon light setups, in commercial situations) - especially when incandescents become no longer available and CFL's are used.

** I think that is really out of the question - be much the same as using a standard CFL on a pulse fired triac dimmer.

Doing that kills them real quick, even if the dimmer is set all the way to max.

..... Phil

Yes but the heat from incandescent bulbs seems to be just as big a problem as the UV from FL's IME. I have replaced *lots* of batten holders that have never seen a CFL. OTOH, I still have some 30 YO tube fittings.

MrT.

Could the spikes be attributed to it being faulty?

Michael

We've been waiting a long time for that. LEDs are still behind in terms of the light output per dollar and the quality of light.

Only just from what I hear and only very recently.

"Michael C" "Phil Allison"

** No.

The phenomenon of current spiking is *characteristic* of using a rectifier with capacitor filter with a standard ( leading edge or pulse fired) triac dimmer.

At some point in each half cycle, the triac suddenly conducts and applies maybe 300 volts to the CFL resulting in the cap after the bridge rectifier charging to full voltage in 50 - 100uS or so. The only limit on the size of the current spikes is the existence of a series resistor and the ESR of the particular electro cap.

Using the same kind of dimmer with a normal 23 watt CFL (ie non dimmable) results in a stream of current spikes of around 20 amps each !!!

This is why you must not use standard CFLs with a dimmer - cos the CFL will likely catch on fire and / or destroy the dimmer by causing the triac to short out.

.... Phil

I thought you could not use them on a Dimmer. Sort of a similar reason you cannot use a Dimmer on a fluro, i.e. the Fluro (CFL) needs a certain voltage to operate, reducing it would lead to a higher current being made by the CFLS electronics, leading to excessive current and burnout.. Allan

"Allan" "Phil Allison"

** Care to explain why the word "dimmable" is on the packet no less than *6 times* as well as on the point of sale advertising ???

..... Phil

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Dimmable CFLS were being discussed here and from what was said, they are about as impractical as an ashtray on a motorbike.

There are (and have been for years) ways to dim standard fluorescents, none of them anywhere as good as dimming with with incandescents and mostly inefficient. here is a document on it that I googled:

There are also special "dimming" ballasts for various installations. From the "blurb" they work well, document is interesting reading regardless.

I would note the comments on the Dimmable CFL too, the same sort of problems (power factor and current surges) might possibly apply with any (or other) electronic dimmable fluro ballasts.

**Did you see where I wrote: "Give it a couple of years"?

LEDs are presently as efficient as fluoros and are very dimmable. Better still, they retain good colour balance throughout the range. Prices are falling more rapidly than I thought possible. There are (at least) three different varieties of white available. Then there are the multi-chip LEDs where three primary colours are mixed, allowing an infinite variation of colours.

**Yep.

--
Trevor Wilson
www.rageaudio.com.au