Compact flourescent lamps - < £0.50 !

[Pooh Bear]

Morrison's supermarket chain

http://www.morrisons.co.uk/default.asp

currently has a special offer on Philips compact flourescent 'bulbs' (
6000h - 60 W and 100 W equivalents - 600 and 1000 lumen - EU energy
grade A efficiency ).

It's a '2 for the price of 1' offer @ 99p ea ! So you're paying 49.9p
! for each 'bulb'. That's similar to the price of a filament bulb
bought individually.

Made in PRC of course.

Graham

 

[Ian Stirling]

Morrison's supermarket chain

http://www.morrisons.co.uk/default.asp

currently has a special offer on Philips compact flourescent 'bulbs' (
6000h - 60 W and 100 W equivalents - 600 and 1000 lumen - EU energy
grade A efficiency ).

It's a '2 for the price of 1' offer @ 99p ea ! So you're paying 49.9p
! for each 'bulb'. That's similar to the price of a filament bulb
bought individually.

Made in PRC of course.

Lumens and watts?

 

[Chris Jones]

Morrison's supermarket chain

http://www.morrisons.co.uk/default.asp

currently has a special offer on Philips compact flourescent 'bulbs' (
6000h - 60 W and 100 W equivalents - 600 and 1000 lumen - EU energy
grade A efficiency ).

It's a '2 for the price of 1' offer @ 99p ea ! So you're paying 49.9p
! for each 'bulb'. That's similar to the price of a filament bulb
bought individually.

Made in PRC of course.

Graham

Or at Robert Dyas you can buy 3x Osram 20W made in germany for 5UKP = 1.66
each,
20W, 15000h 1200 lumens, 500000 on/off cycles

Next best that I know is sainsburys which sells a range of power ratings
(Osram) all for 2.19 each. I wanted some 11 Watt because I think they
might be able to run reliably on DC (from a DC-DC converter), though I have
seen conflicting information about this on Osram's websites in various
countries.

Chris

 

[Ian Stirling]

(Osram) all for 2.19 each. I wanted some 11 Watt because I think they
might be able to run reliably on DC (from a DC-DC converter), though I have
seen conflicting information about this on Osram's websites in various
countries.

On all probably 5 or 6 makes of CFL I have dissasembled, they have a
rectifier before the energy storage cap, and hence will run just fine
on DC (340V in the UK).

(though I find a goodly number will run on about half sticker power at 150V,
but probably doing bad things to the tube)

 

[Chris Jones]

On all probably 5 or 6 makes of CFL I have dissasembled, they have a
rectifier before the energy storage cap, and hence will run just fine
on DC (340V in the UK).

(though I find a goodly number will run on about half sticker power at
150V, but probably doing bad things to the tube)

I have seen older articles recommending DC operation of CFLs:
http://www.siliconchip.com.au/cms/A_102473/article.html

I have heard that newer tubes require a voltage lower than 340V if smooth DC
is used, because they choose the smoothing capacitor to be much smaller
than that which would be necessary to maintain a steady DC voltage on the
cap with mains input, therefore they expect a lower average voltage than
340V. I can only guess that this is a combination of cost cutting and
measures to improve the harmonic content of the input current.

I have seen an inverter circuit which is designed to drive these newer CFLs,
but it seems very complicated to me, and I would rather find a combination
of CFL type and DC voltage which is reliable without having to replicate
the waveform of rectified normal mains.
http://www.siliconchip.com.au/cms/A_102412/article.html

There is a special model of the Osram CFLs which is called 'facility' and
which is specified for DC operation. Also various ordinary Osram CFLs are
mentioned on some Osram websited as being able to run on DC, though these
websites do not seem to be in complete agreement about which models are
suitable.

They used to have a FAQ which discussed this but they have deleted it, and I
can only find foreign language versions now with google, and a version in
English which is only in google's cache but which comes up 404 on Osram's
website.
http://www.osram.com/pdf/service_corner/DULUX_Sortim.pdf
http://66.249.93.104/search?q=cache:sdxOwF9Fv_wJ:www.osram.com.ro/
(url continued.....) service_corner/faq/general/compact.html
http://www.osram.fr/faq/faqfluocompactes.php

Chris

 

[John Woodgate]

I read in sci.electronics.design that Chris Jones

I have heard that newer tubes require a voltage lower than 340V if
smooth DC is used, because they choose the smoothing capacitor to be
much smaller than that which would be necessary to maintain a steady DC
voltage on the cap with mains input, therefore they expect a lower
average voltage than 340V. I can only guess that this is a combination
of cost cutting and measures to improve the harmonic content of the
input current.

It's primarily to meet the very stringent harmonic current emission
requirements, Class C of IEC/EN 61000-3-2. The lower cost is a welcome
spin-off; usually meeting EMC requirements costs money.

 

[Pooh Bear]

Just out of interest, can you meet these requirements by putting a low
value, huge power rating resistor in parallel with your product's power
input? This could make the regulations counterproductive.

I hate standards that you have to pay money to read. It's an obstacle to
competition.

It's a 'tax' on business effectively. Popular in the EU where pen pushing is
deemed more of a worthy exercise than real work.

Graham

 

[John Woodgate]

I read in sci.electronics.design that Chris Jones

Just out of interest, can you meet these requirements by putting a low
value, huge power rating resistor in parallel with your product's power
input?

Yes, but no-one does. Getting rid of the heat cost money.

This could make the regulations counterproductive.

No, it doesn't. As far as the electricity suppliers are concerned, it's
the ratio of harmonic to fundamental current that matters most, because
if you pay for a lot of fundamental, you can be allowed some harmonics.
But the absolute values of harmonic currents are indeed important in
terms of excess I^2R losses, excessive voltage across supply-system
inductors and excessive currents through supply-system capacitors.

 

[Chris Jones]

I read in sci.electronics.design that Chris Jones


It's primarily to meet the very stringent harmonic current emission
requirements, Class C of IEC/EN 61000-3-2. The lower cost is a welcome
spin-off; usually meeting EMC requirements costs money.

Just out of interest, can you meet these requirements by putting a low
value, huge power rating resistor in parallel with your product's power
input? This could make the regulations counterproductive.

I hate standards that you have to pay money to read. It's an obstacle to
competition.

 

[Zak]

There is a special model of the Osram CFLs which is called 'facility' and
which is specified for DC operation. Also various ordinary Osram CFLs are
mentioned on some Osram websited as being able to run on DC, though these
websites do not seem to be in complete agreement about which models are
suitable.

If it is not specified it is probably not suitable. Given how cost
reduced these designs are I would not be surprised if the AC ripple is
somehow needed to keep things in spec.

These product lines even have their own components designed for them.


Thomas