Back in the 1960s, when tubes were coming into service more and more, it
was a widely held belief that they were more expensive to run than
tungsten filament bulbs if turned on for short periods. It was said that
most of the power they consumed was drawn during the 'strike-up' phase so
if they weren't on for at *least* an hour, you might as well be using TF
Well, here we are 50+ years on and tubes are now very much old tech.
What, with the benefit of hindsight, have the Panel to say about those
old efficiency claims of the day?
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That is what I was taught, but the calculation also involved wear and
tear on the tube/starter/choke. I still will not install any sort of
discharge lamp where it is liable to constant switching though.
They were never true.
What was the case was that each switch-on wore the tube out by the
equivalent of some hours running. The instant-start fittings which
were common in the US suffered from this particularly badly. The
switch-start used in most 220-240V countries much less so, but it
was still a significant effect.
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Well yes you had to use heaters and stir things up. I cannot say that \I've
had tubes in quickstart electronic ballasts go more often than the normal
starter switched ones.
All in the end end up with black ends and the first indication is that in
cold locations they can and do have trouble staying lit till they warm up.
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On Sun, 16 Sep 2018 16:11:54 -0000 (UTC), Cursitor Doom
Yes of course they are more expensive. The light output is of a
frequency that resonates with the thought patterns of muslim child
molesters boosting their desires and leading to increased rumpy pumpy
with our fine British schoolgirls.
The wavelength of the light could with the oscillatory nature means
that peoples eyesight can be damaged and our poor British heroic
houswives will not see rapidly moving kitchen equipment due to the
"strobe" effect. This will lead to increased work for the NHS and if
foreigners are subjected to the same risks, they will have an unfair
advantage over white people as their fingers are darker and easily
found amongst the ingredients for dinner.
If I were you, I would vote to get them all scrapped in favour of
going back to incandescent lighting.
Importing whale oil and candle wax will be a tremendous boost for
Britains economy, we could have trade deals with Japan in almost no
time and the need for lamplighters would give employment to UK
citizens once they have spent a year or so being trained.
By putting Whale oil lamps in operating theaters, the NHS would save
£1,256.43P a week.
On Sunday, 16 September 2018 17:11:57 UTC+1, Cursitor Doom wrote:
it was a misunderstanding. They used around 3x the current for the 1st 1-2
seconds during starting, but not 3x power. Starting added wear & tear to th
e tube filaments. That's all. ISTR calculating the break even point many ye
ars ago at somewere vaguely around a minute.
I meant much more efficient than the alternatives to fluorescents were then.
Yes, fluorescents still arguably have their place now,
but that isnt for efficiency, it’s the much longer life of the
long tube fluorescents than you can be sure of with leds.
Useful though that is, I'd say lumens at the work surfaces are the more
important, especially in a kitchen where those surfaces are even further
off-axis from a downwards directed light source than the extent of the
Personally, I find that an overall light is better than a directional one. A
4000 lm florrie that shines all around seems better than a directional (even
180 deg+ LED). Under-cabinet lights are the exception.
On Sun, 16 Sep 2018 16:11:54 +0000, Cursitor Doom wrote:
There was *some* justification for that belief but it wasn't electricity
costs, it was premature wear of the thoriated cathode filaments due to
the use of the cheap 'n' nasty switch starter.
Fluorescent lamps are discharge lamps which, in common with all lamps of
that class, have a negative impedance characteristic which needs to be
swamped out with a positive impedance wired in series. Their efficiency
was so much better than the incandescent filament lamps they replaced
that even with the losses of a resistive ballast on a 230vdc supply, they
still gave off two or three times more light of a tungsten filament lamp.
However on AC supplies, it became possible to replace the ballast
resistor with a ballast choke to provide a much less lossy positive
impedance. The only downside being the inductive (lagging) current
component this added to the load on the mains supply which increased the
wattless amperage which, as far as the PSUs were concerned weren't
wattless when it came to the I squared R losses in their transmission
The solution was to mandate that a power factor correction capacitor be
wired across the mains input of each light fitting using a tube with a
rating higher than 20W in order to reduce this inductive loading to an
The filaments in fluorescent tubes were designed to run at full heat
from the short circuit current of the ballast choke so that a simple neon
heated bi-metallic switch could be used across the lamp as a crude
starter. It worked but at great cost to tube life when used in frequently
When such lamps were only switched once or twice a day, there was no
point in upgrading to a "Quickstart"(tm) transformer to give flicker free
almost instant reliable wear free starting that would let you treat it
like an ordinary filament lamp and still get the 7 to 12 thousand rated
hours of life before it dropped to the 80% of design lumens point deemed
to be the most economic point at which to replace it (generally several
thousands of hours before it would actually fail to fire up properly).
Rather annoyingly, the newer T8 reduced mercury fill lamps will no
longer fire up on a Quickstart ballast. For me, that meant shelling out
on an electronically ballasted fitting from B&Q when the missus insisted
on my replacing the older fluorescent fitting in our kitchen after we'd
had the ceiling repaired post flat roof leak.
Unfortunately the B&Q fitting turned out to have been cursed with a
'Dumb' Chinese made ballast which caused the T8 lamps to fail faster than
the old fashioned switch started units used to, simply on account of the
fragility of "modern" inadequately dosed with mercury T8 "high
efficiency" tubes due to the aggressive 'instant start' characteristic of
the 'dumb' electronic ballast.
Luckily, the ballast failed about 18 months and two lamps later, forcing
me to buy a proper microprocessor controlled replacement (about £4.70
delivered) which finally put paid to the problem of short tube life.
Although I'm resigned to the unimpressive 900ms start up time (flicker
free mind!), it seems we've paid a high price for our high efficiency,
inadequately mercury dosed fluorescent tubes when I recall the 300ms
startup and extremely long life of the older adequately mercury dosed T12
tubes of yesteryear running on Quickstart ballasts.
I know that fluorescent lighting is obsolescent technology biding its
time for decent (and cost effective) LED based linear tubes to become
worth investing in as an upgrade in areas where a diffuse source of
bright lighting is required without having to go to the expense and faff
of fitting LED ceiling panel luminaires, hence my replacing the ballast
to carry on using the existing fluorescent lamp fitting in our kitchen.
Eventually, we might finally start to see 200LPW (more reliable) LED
ceiling panels making an appearance in the next 5 to 7 years. I reckon I
will have finally made my ROI on the existing light fitting just about
Yup, from an electrical point of view was a load of nonsense at the time
and still is...
If you think about it, say your tube draws 0.25A once lit, if you want
to draw an hours worth of energy in (say) 5 secs, you will need to pull
3600/5 or 720 times the current. That'a 180A - or enough to trip a 32A
circuit breaker instantly, let alone a 6A MCB or 5 amp fuse.
There is some truth in that there is extra cost to start the lamp but,
that is down to accelerated wear on the starting filaments which will
reduce the total lamp life (or at least the available number of
"starts"). Since they were quite expensive at the time, there was a
financial cost associated with that reduced life. So there was some
sense in not turning them off for very short durations.
Probably more wrong now than then since modern tubes are far cheaper,
and probably survive more starts anyway due to better control gear.
It was rubbish unless the system was very badly designed as far as I know.
There were of course tubes made that were only dual pigment which were not
as bright as the later ones were too, which meant that efficiency was not
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On Sunday, September 16, 2018 at 5:11:57 PM UTC+1, Cursitor Doom wrote:
Might be cheaper to run but the frequency with which the bastard things in
my kitchen (under-cabinet downlighters) need replaced outweigh the benefits
. Even with replacing the starter at the same time as the tube I'm lucky if
they last a few months* Meanwhile the monolithic monsters in the garage wh
ich must be coming up for 20+ years old are still fine.
*I have looked into replacing the ballast but I'm buggered if I can find a
simple how-to guide - it's all "if this then this otherwise this unless thi
s". I might just skip straight to LEDs but find them a bit cold.
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