CFL ballast design, and using dead lamps for repair

Can lights aren't ventilated. In fact, many are insulated (IC rated). They're hell on CFLs.

"Ian Field" <

** See the second half of this page for pics of the actual CFL and fitting.

The are no ventilation a holes at the back of the fitting and all the spiral CFLs were a neat fit.

... Phil

One other thing you can learn from this exercise - low cost part types.

Typical gapped core sizes commonly used in this application can be designed in elsewhere for $0.02. Similar price ranges for bobbins, semiconductors, film caps, fuses and electrolytics.

Lots of other things you can do with this stuff, knowing you won't be beat on material cost.

RL

Even stupid people should know better than put CFLs in a fitting like that!

I must be stupid then. I've got a CFL in a totally sealed (shower) fixture and it's been working fine for years. (I even conformally coated the lamp before sealing it in the fixture).

I only buy name brand (eg. Philips) products though, and probably they're made a bit better than the ones that come 8 to a card. Never seen any perforation of the housings on failure.

Nope. I lost three Philips to one power surge and on pulling them apart I can confirm they use the same caps or worse - mine were marked as 350V DC. Considering the mains was 240v AC thats not a lot of a safety margin. I now use whatever is cheapest seeing as it makes no difference to the quality.

In a TV or monitor you'd find 385V minimum, more likely 400V. Although nowadays with PFC front ends, there's no rectifier-reservoir electrolytic, the PFC unit is essentially a boost converter, so the main electrolytic would be about 450V.

Parts that are marked the same are not necessarily the same. The $1.00 bulbs may contain gold-colored caps marked as 630VDC/125°C.

Not sure if the 240V input makes much difference.. they are likely using a doubler circuit in our (120V) lamps.

I have heard enough stories of people who bought the cheap ones and had initial failures, exciting failures, and such like to avoid the low end stuff.

It would be nice if LED lamps got anywhere close to the brightness of CFL, halogen or incandescent bulbs at a reasonable price, but they are not very close yet. Maybe in a few years. I bought a couple MR11 "brightest on the market" bulbs to unload the halogen xfmr and allow me to put a bigger halogen in the centre bulb of a 3-light string, and they're not even comparable. I'll have to take some quantitative measurements at some point.

Last time I saw LED "bulbs" in the supermarket, they were significantly less lumen/W, several times the price and you'd need at least 3 (at 9W each) to equal the light output of an 18W CFL.

LED lighting in the style similar to LV halogen type is supposedly up to the job.

Lumens per watt is probably okay. The problem is that they're using discrete SMT LEDs and the $ per incremental lumen is far more than for a CFL.

These are the ones I bought.

I'd prefer to have 50W or 100W equivalent that burns 5 or 10W.

.

he

g.

ral

Nice artcile Phil, But don't worry about the legislature's doing anything. What's needed is some lawayer to get a hold of it and sue the manufacturers.

(That's the US way :^)

George H.

The offshore manufacturers are probably not easy to get substantial judgements against- but the stores, especially those who do their own importing, have deep pockets and can't easily escape.

They do have a good defense though- if it has safety agency approval, it's presumed to be safe. Maybe report it to the safety agencies- but I don't see anthing there that would really raise the alarm- incadescents break and short internally and implode from time to time, and none of the burn- through incidents shows support of combustion. Any fixture designed for a normal incandescent ought not to burn the office or house down. The one that 'exploded' is the closest one- the mfr may have substituted a cheaper non-fiberglass sleeving on that diode.

P.S.

Sold at: Discount stores in New York, New Jersey, Pennsylvania and Connecticut from January 2008 to December 2008 for between $1 and $1.50.

Manufactured in: China

"Spehro Pefhany"

** The plastic bases of most CFLs simply push fit together - so only a small explosion inside will blow the top part off.

Small bits of glass were strewn from one end of the kitchen to the other ( when I arrived with my camera ) and some bits had landed on the benches - so it seemed the spiral tube must have exploded in mid air. The filaments were both intact so the only explanation I have is that the glass spiral impacted hard against the inside of the lamp fitting before falling in pieces.

... Phil

Spehro Pefhany wrote in news: snipped-for-privacy@4ax.com:

If you want relatively unbiased & consitent tests of LED bulbs, check out:

You have to promise that you aren't a commercial operation to see the full reports. The reports tend to lag a bit behind the latest technology, but the quality is going up & the prices are coming down.

I have a couple of LED bulbs in special applications, and they work very nicely. I use a couple MR-16 replacements in gooseneck illuminators on my milling machine because I got tired of toasting myself with the halogen bulbs. I've also installed these:

in stairwells where I want instant full brightness. They work great. They also actually cost a lot less than the dimmable CFL retrofit units I installed a number of years ago.

Doug White

Grin sure sue everyone,

OK maybe it will be the insurance company lawyers sueing for fire damage.

I haven't had many problems with cfl's, except for globe units in the (steamy?) bathroom.

George H.

If they come apart easily by pulling and expose the mains potential, I would not think that would pass muster with the safety agencies. It's been a while since I've tried to take one part, but I recall whole rows of snaps that are not easy to disengage.

Does Australia enforce national safety standards on the sale of mains-powered goods?

Best regards, Spehro Pefhany

--
"it's the network..."                          "The Journey is the reward" 
speff@interlog.com             Info for manufacturers: http://www.trexon.com 
Embedded software/hardware/analog  Info for designers:  http://www.speff.com

Many of the early types sold in the UK were fairly easy to pry open and could be clipped together again easily - the most recent Philips one's I bought are much more secure - you pretty much have to destroy the case to pry it open.

"Spehro Pefhany"

** See the word "explosion " ??

A tool ( ie screwdriver) is needed to open most CFLs and that is adequate to pass safety rules anywhere.

... Phil