From: phil-news-nospam on
In alt.engineering.electrical J. B. Wood <wood(a)itd.nrl.navy.mil> wrote:

| IIn article <ZMKdnXMu2Jg8857bnZ2dnUVZ_rqhnZ2d(a)comcast.com>, "hob"
| <dehoberg(a)comcast.net> wrote:
|> Draperies, silk lamp shades, and some plastic shades absolutely also do
|> not like fluorescent lights, nor does fine art - and many things in
|> bathrooms are plastic and will yellow in fluorescent light.
|>
| Hello, and while I can't comment on the above, I can say the only thing
| stopping me from exclusively using fluorescent fixtures in my home is that
| my eyes quickly get fatigued while reading under artificial electric light
| other than incandescent. Sincerely,

That happens to me, too. This has been said to be due to things like poor
color and flicker. But what I believe is the true cause is continuity of
the spectrum (specifically, lack thereof). FL light has 2 narrow and 1 wide
spike in the spectrum, with a gap in between. Eyes (and especially when
corrective lenses are applied) do not focus all colors uniformly and will
tend to focus somewhere in the middle of the nornally continuous white light
spectrum. However, a spikey spectrum creates a situation where there are 2
or even 3 distinct focal zones, and the eye wants to jump between them. This
happens with sharp edges of black on white where the boundary is present in
all the spiek wavelengths. What the eye sees is disjoint boundaries, and
thus it tends to jump in focus. The fatigue is from the eyes doing a lot
more focusing work (including opening and closing the iris more to try to
find a consistent focus).

If you can't have broad continuous white light, then what you need is to
confine the spectrum to a single color, red or green. Red is actually best,
but green works reasonably well. A true monochromatic yellow would also
work (e.g. not a yellow made from mixing red and green). One way to get
such light is a deep color gel over a FL light source. Another is using
single color LEDs (all the same color).

I have hypothesized that a mix of a sufficient number of single wavelengths
would approximate a continuous spectrum well enough for the eyes to no longer
have this problem. A future project plan is to build a light box made up of
a large number of different LED chips. I've found at least 22 distinct
wavelengths I could get some LEDs in. Then I'll need to balance them to
achieve some approximation of white.

I experienced the above problem with a light source based on a white LED
powered directly with DC. So I know flicker is not the issue (despite the
fact that I can see it in virtually all FL lighting). I also experience
it with CRT screens where I have addressed the issue with selective colors
for the text so that the boundary between text and background is only in a
single color (remaining colors are then at a uniform level and present no
edges at the text). I can have red text on black, or I can have yellow
text on green and it's the same red edge. Cyan text on white presents a
red edge in reverse (but that's too much light for the available contrast).
Magenta text on white (green edging) almost works. I end up using orange
on dim green most often.

--
|---------------------------------------/----------------------------------|
| Phil Howard KA9WGN (ka9wgn.ham.org) / Do not send to the address below |
| first name lower case at ipal.net / spamtrap-2007-03-23-0757(a)ipal.net |
|------------------------------------/-------------------------------------|
From: Jeff on
Andrew Gabriel wrote:
> In article <13057unke3a6958(a)corp.supernews.com>,
> Brian Elfert <belfert(a)visi.com> writes:
>
>>"throwitout" <throwitout(a)dodgeit.com> writes:
>>
>>
>>>The absolute leading edge would be T5s, however there are other
>>>concerns with them, you must replace the fixtures (different length
>>>tubes) and the equipment isn't as run of the mill as T8's.
>>
>>I thought I read somewhere that T5s are actually less efficient than T8
>>bulbs.
>
>
> On electronic control gear, there's no difference.
> T8's on magnetic control gear are around 10% less efficient.
> (The T5HE and T5HO tubes only run on electronic control gear.)
>
> T5 tubes, having a thinner light source, enables luminaire optics
> to be designed to direct the light more accurately, which can mean
> less wasted in spillage and reabsorbtion into the tube. This can
> make T5 luminaires more efficient even when the tubes themselves
> are the same. T5 tubes are still more expensive and tend to have
> a rather more limited range of colour temperatures and CRIs
> available, so unless the thinner tube size is an advantage to
> you, T8's are probably a better choice at the moment.
>
>
>>I know that electric utilities are generally no longer offering incentives
>>to install T8 fixtures in commercial buildings as T8s are the default for
>>new buildings and remodeling.
>
>
> In the UK, T12 luminaires haven't been available for around 25
> years now. T12 tubes are available for old luminaires, but they
> are low volume products, and many stores no longer stock them.
> Almost all our T12 luminaires can take T8 tubes anyway (this is
> only true in 230V countries, and not in 120V countries).

What about in the US and 120v (autotransformer ballasts)? Can I put a
T8 tube in an old T12 fixture (with starter)? I see that there are
energy savings by going to T8, even with using a magnetic ballast. Are
starters dead, and everything instant start now? In my home I've gone
totally CF and hadn't even thought about linear fluorescents.

Jeff
>
From: Jeff on
TKM wrote:

> "Jeff" <dont_bug_me(a)all.uk> wrote in message
> news:0DeMh.16044$Jl.10498(a)newsread3.news.pas.earthlink.net...
>
>><snip>
>>
>>>As a lighting designer, I now treat fluorescent lamps as I treat
>>>incandescent lamps. If the light is not needed, turn them off for both
>>>cost and energy savings. A house which was built new four years ago and
>>>for which I designed the lighting has 75 fluorescent lamps -- most are
>>>used for indirect room lighting on gloomy days. But I put fluorescent
>>>lamps in the bathrooms, closets and other areas where the lamps are
>>>turned off and on numerous times each day. There have been no lamp
>>>failures of either the linear or CFL types to date.
>>
>> Whats the current technology for linear flourescents? My Dad put in
>>linear single tube fluorescents all the way around the living room in an
>>alcove. These lamps have the twist in starters. The wiring has
>>deteriorated (brittle) and I'd like to either rewire these or replace them
>>if the technology has moved on. I suspect it was these old fluorescents
>>that were known for the sizable turn on surge.
>>
>> Jeff
>>
>>>TKM
>
>
> Wow. Time to upgrade that system.

I think so. Installed back in the 40's.

I can imagine how the lamps must blink,
> flash and flicker at turn-on. But upgrading is relatively easy and a new
> system will be 20-30 per cent more efficient. For the following, I assume
> you now have 4-foot lamps and simple strip or channel fixtures.

A mix of lengths as the cornice goes around corners. Mostly 4' and
perhaps the other was 18". Dad liked fluorescents and used them
throughout the house. Sometimes as auxillary lighting (as in the cornice
lights, boy did the room light up when they were on!) and other places
as the primary.

You can
> choose to keep the existing strip fixtures; but I would recommend replacing
> them so you have new lamp sockets too. A good replacement lamp is the 32
> watt T8 which is also a 4-foot lamp. That lamp is easy to find, relatively
> inexpensive, rated for 20,000 hours life and is available in a warm color
> (3000K, CRI=80+ is best for home use in my view).

Thanks.
>
> Power the lamp with an electronic instant-start ballast. You can use either
> a single-lamp or a two-lamp ballast, but the wiring with the two-lamp
> ballast is a little more complicated since there is a ballast just in ever
> other strip fixture. However, that's the cheaper solution. I've used the
> Universal electronic ballast B2321120 RH-A quite a bit.

I'll do that next time I'm back there. I'm striking out on googling that
number, or part of it. I did find one on Ebay for $28.00. Is that the
going rate? The one ballast for two fixtures is sounding reasonable!

Google that catalog
> number and you'll get the technical specifications, wiring diagram and some
> sources of supply.
>
> No, there was no turn-on power surge with your old system -- just a few
> current pulses as the starters operated.

I remember a lot of flickering.


I wonder where that rumour came from.

Jeff
>
> TKM
>
>
From: TKM on

"Jeff" <dont_bug_me(a)all.uk> wrote in message
news:PM2Nh.130703$_73.93920(a)newsread2.news.pas.earthlink.net...
> Andrew Gabriel wrote:
>> In article <13057unke3a6958(a)corp.supernews.com>,
>> Brian Elfert <belfert(a)visi.com> writes:
>>
>>>"throwitout" <throwitout(a)dodgeit.com> writes:
>>>
>>>
>>>>The absolute leading edge would be T5s, however there are other
>>>>concerns with them, you must replace the fixtures (different length
>>>>tubes) and the equipment isn't as run of the mill as T8's.
>>>
>>>I thought I read somewhere that T5s are actually less efficient than T8
>>>bulbs.
>>
>>
>> On electronic control gear, there's no difference.
>> T8's on magnetic control gear are around 10% less efficient.
>> (The T5HE and T5HO tubes only run on electronic control gear.)
>>
>> T5 tubes, having a thinner light source, enables luminaire optics
>> to be designed to direct the light more accurately, which can mean
>> less wasted in spillage and reabsorbtion into the tube. This can
>> make T5 luminaires more efficient even when the tubes themselves
>> are the same. T5 tubes are still more expensive and tend to have
>> a rather more limited range of colour temperatures and CRIs
>> available, so unless the thinner tube size is an advantage to
>> you, T8's are probably a better choice at the moment.
>>
>>
>>>I know that electric utilities are generally no longer offering
>>>incentives
>>>to install T8 fixtures in commercial buildings as T8s are the default for
>>>new buildings and remodeling.
>>
>>
>> In the UK, T12 luminaires haven't been available for around 25
>> years now. T12 tubes are available for old luminaires, but they
>> are low volume products, and many stores no longer stock them.
>> Almost all our T12 luminaires can take T8 tubes anyway (this is
>> only true in 230V countries, and not in 120V countries).
>
> What about in the US and 120v (autotransformer ballasts)? Can I put a T8
> tube in an old T12 fixture (with starter)? I see that there are energy
> savings by going to T8, even with using a magnetic ballast. Are starters
> dead, and everything instant start now? In my home I've gone totally CF
> and hadn't even thought about linear fluorescents.
>
> Jeff

No, you can't put a T8 tube in a fixture powered with a T12 ballast and
starter. The voltage and current values that the ballast provides are
different and T8 lamps are not designed for starter circuits.

You could replace the ballast with one designed to operate T8, remove the
starter and put a T8 lamp into the fixture though since the lamp length and
sockets are compatible.

Starter circuits are virtually gone along with magnetic ballasts since
electronic ballasts which are now smaller, lighter, more efficient and less
expensive don't need starters. They can be designed to start fluorescent
lamps in either instant start or rapid start mode.

TKM



From: Andrew Gabriel on
In article <PM2Nh.130703$_73.93920(a)newsread2.news.pas.earthlink.net>,
Jeff <dont_bug_me(a)all.uk> writes:
> Andrew Gabriel wrote:
>> In the UK, T12 luminaires haven't been available for around 25
>> years now. T12 tubes are available for old luminaires, but they
>> are low volume products, and many stores no longer stock them.
>> Almost all our T12 luminaires can take T8 tubes anyway (this is
>> only true in 230V countries, and not in 120V countries).
>
> What about in the US and 120v (autotransformer ballasts)? Can I put a
> T8 tube in an old T12 fixture (with starter)? I see that there are

I don't know for sure, but I don't think so.
T8's in 230V countries were designed for exactly this. They
are reduced power but same light output as the original T12.

On US 120V supplies, control gear is more complex and there
are more different designs available, and I suspect it wasn't
possible to design a lower power tube which would retrofit
into these different control gear designs are work safely
and reliably. The US T8 tubes are even lower power than those
used in 230V countries and hence produce less light than the
T12's of the same length. That may be why T12's are still
popular in the US, but very rarely seen in the UK nowadays.

> energy savings by going to T8, even with using a magnetic ballast. Are
> starters dead, and everything instant start now?

Starters still very common on 230V supplies. There is an EU
directive requiring improvements to control gear efficiency
over a number of years, and originally it was though this
would render magnetic ballasts obsolete. However, manufacturers
just made them more efficient so they continue to meet the
specs. Given they are much cheaper and more reliable than
electronic control gear (and from what I hear, much more
reliable than US magnetic ballasts which are inevitably more
complex due to lower mains voltage), they continue to be used.
Magnetic ballast instant start has never existed in the UK,
and I don't recall seeing it anywhere else other than the US.

--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]