Low Voltage Halogen VS. 120v Halogen lighting
Jason
rooms of my house. I noticed that there are 12v halogen light that
require a transformer and there is also 120v halogen lights that
don't.
Can anyone please tell me the advantages of one of the other?
Things that concern me are:
1. Cost of lights
2. Amount of electricity used
3. Dimability. I want to use dimmers and I have heard that you need
special dimmers for low voltage lights. True?
Thanks
J
Wayne
think the only real difference is the power saving as far as the circuit
goes so you can put more lights on the circuit since watts=Volts* amps!
Wayne
"Jason" <Jaso...@mail.com> wrote in message
news:439c4a9c.0205...@posting.google.com...
Ramman
is directly related to power dissipation, all other things being equal. If a
Halogen light puts out a certain number of lumens per watt and watts=
volts*amps, for a low voltage bulb (ie 12v) you would need 10* the number of
amps to produce the same amount of light as with a 120v bulb.
Richard Greene
"Wayne" <Way...@nospam.uswestmail.net> wrote in message
news:Se%D8.28547$UV4.5890@rwcrnsc54...
Anthony Straight
The advantage of LV lights over standard voltage lights is that they can be
focused more tightly in the same size lamp. The reason is that the filament
is smaller in lower-voltage lamps. For general lighting, it is of no
particular advantage to use LV lamps.
1. The LV light fixtures generally cost more, and so do the dimmers.
2. The power consumed is nearly the same.
3. Special, rather pricey, dimmers are required for transformer-operated
lights.
--
Best regards,
Anthony Straight
proprietor, Tony Electric
http://dotznize.com/electric/
[This free advice carries no warranty whatsoever. Use it or ignore it at
your own discretion and risk.]
Chas Hurst
close to sunlight or? I believe halogen lamps do not like dimmers. Do a Google search.
Chas Hurst
"Ramman" <r.gr...@ieee.org> wrote in message news:bC%D8.6894$v81.8...@bin4.nnrp.aus1.giganews.com...
Doug B Taylor
You have one other item to consider, besides the responses given so far, and
that is the ballast/transformer used in 12v pot lights. They do burn out and
in residential construction they tend to burn out more frequently due to the
limited air flow and space for heat escape. They can also 'hum', which may
become very annoying.
In my opinion you can get away with a relatively cheap 120v pot light
fixture with a nice trim, but if you go with 12v fixtures do not buy the
cheapest. The cheapest 12v fixtures have cheap ballasts and you will be
forever replacing the ballasts. Replacing ballasts is a pain in the butt.
I would only add that with regard to heat, you are stuck. The higher the
wattage the more heat. You must, of course, maintain spacing around the
fixture housing per the electrical code and the manufacturers
recommendations. If you have insulation in the ceiling you must use an "IC"
rated fixture.
Regards,
Doug Taylor
"Jason" <Jaso...@mail.com> wrote in message
news:439c4a9c.0205...@posting.google.com...
Don Klipstein
>Could you please explain this a bit further. Light output as I
>understand it is directly related to power dissipation, all other things
>being equal. If a Halogen light puts out a certain number of lumens per
>120v bulb.
There is a little-known property of incandescent lamps ("light bulbs"):
There is indeed an "ideal voltage" which maximizes the efficiency of a
design for a given wattage and life expectancy.
The reasons: If the design voltage is higher than ideal, then the
longer, thinner filament evaporates more quickly and has to be run at a
lower temperature for the same life expectancy. The lower temperature
shifts spectral output from visible to infrared (although even in the best
case - at the melting point of tungsten - the radiation is roughly 1% UV,
18% visible, 81% IR).
In addition, all halogen lamps and most other incandescent lamps have a
gas fill, and energy lost from the gas conducting heat from the filament
is surprisingly proportional to the visibly apparant length of the
filament and surprisingly independent of the diameter of the filament.
A thinner filament has an almost correspondingly thinner "boundary layer"
of surrounding gas heated by the filament, with a proportionately higher
temperature gradient, and this makes heat conduction energy loss about
proportional to filament length but not varying much with filament
diameter.
These are reasons why a shorter, thicker filament has higher energy
efficiency than a longer, thinner one.
One can be excessively extreme in low voltage design - an excessively
short and thick filament has high cross section area and high temperature
gradient in its ends, and heat conduction from the ends becomes a
significant energy loss.
Now for what is the most efficient design voltage for incandescent
lamps: This varies with voltage:
For a fraction of 1 watt, 3-5 volts with a vacuum.
For around 1 watt, around 6 volts with a vacuum.
For a couple to a few watts, around 6 volts with a gas fill with a
singly coiled filament.
For around 10-20 watts, around 10 volts with a gas fill and a singly
coiled filament.
For around 25-100 watts, around 12-14 volts with a gas fill and a
singly coiled filament.
For a couple hundred watts, around 20 volts with a singly coiled
filament.
For several hundred watts to a kilowatt or two, jump to about 50-80
volts and with a coiled-coil filament.
If the voltage is well above "optimum" and the current is at least about
.3 amp, a coiled-coil filament is better than a singly coiled one and
gas fill is better than a vacuum.
If the voltage is well above optimum and current is near or below .2
amp, then best design is usually with a vacuum. In a vacuum, degree of
coiling of the filament does not matter as much but it is normally
singly coiled mainly to avoid excessive length. Coiling has a slight
efficiency advantage even in a vacuum - the filament has to be made with
more surface area, with both length and diameter increased, if some of
the light is absorbed by nearby pieces of filament. The thicker
filament will normally either last longer or can be operated at a higher
temperature.
As for how much of an efficiency advantage does a 12 volt lamp have over
a 120V one? At lower wattages this gets significant. The 1156 automotive
bulb at 12.2 volts consumes 25 watts, has an average life expectancy
around 2100 hours, and a light output of approx. 340 lumens. Compare to
around 230 lumens for a 120V 25W lightbulb of similar life expectancy.
A 93 automotive bulb at 11.5 volts has an average life expectancy around
2500 hours, produces approx. 130 lumens of light and consumes approx.
11.8 watts of power. Compare to a 120V 15W lightbulb of similar life
expectancy which produces 110-125 lumens of light.
However, with the cost and energy losses of transformers, I doubt the
energy savings of low voltage lights are really significant. I think the
main advantage of low voltage is safety aspects and ease of use where
120V has hazards to mitigate.
For real energy savings, there are compact fluorescents lamps with power
consumption of 15-18 watts and designed for a wide temperature range -
especially on the cold side. Look in Sears and Home Depot for Philips
"Outdoor" ones - the tubing is in an outer bulb. Put one of these in an
enclosed fixture, and after warming up a few minutes they will reach
nearly full light output in temperatures down to below zero and windchills
to at least -20 on the new scale or -40 on the old scale. (Note -
windchill is only a very rough guide for chilling of exothermic objects
other than human bodies.)
- Don Klipstein (d...@misty.com, http://www.misty.com/~don/index.html)
forrest
"Doug B Taylor" wrote in message > Hi Jason:
> They can also 'hum', which may
> become very annoying.
i would second this, don't estimate the noise that the transformer makes. it
is plainly audible if there is no other source of noise in the room. in one
house i worked on, we ended up putting LV spots in the ceiling of the
2-story stairwell (for precision lighting of art on the walls) but decided
against them for the living room ceiling because of the noise.
--
forrest
___________
forrest underscore m at hotmail dot com
Ralph Hertle
Tungsten-Halogen lamps (e.g., 50V. or 120V.) produce more
visible light than ordinary light bulbs because they can be operated
at higher temperatures.
The tungsten filaments would burn out (thin and break), and the envelopes
would blacken considerably with a layer of black tungsten atoms
if there if the halogen gas were not present in the glass envelopes.
Ordinary lamps (light bulbs to us commoners) without the halogen
gas must be operated at a lower temperature. Alternatively, T-H lamps
are commonly operated at temperatures of up to 5500 deg. Kelvin. Ordinary
lamps that you get at the supermarket usually operate at 2900 deg. K. to
3500 deg. K.
The color of the light is different according to the temperature of the
tungsten filament. The Kelvin color temperature scale is used to provide
a scale of general color spectra ranging from the dull glow of (next to
infra-red heat and nearly invisible) red light at 1000 deg. K. of the heating
element of an electric range on up to the blue-white color of Solar daylight
at 5500 deg. K. The scale reaches lower and higher, however, ordinary
lighting doesn't fall within that greater range.
Ordinary ultra-long lasting lamps are operated at 2900 deg. K. and have
a decided yellow-orange-white light. They have zero violet, zero
cool blues, and less warmer blues. They have a friendlier, warmer color at
2900^ K. than the 5500^ K. color. The lamps last a long time, however, the
colors of certain fabric patterns, clothes, and works of art may look rather
bleak, old, and yellowish.
Color temperature is the general cast of light that seems to be the same
color as light emitted from a tungsten filament operated at a certain
temperature, and the color is measured in degrees Kelvin. A photographer's
light that has a lamp that operates at 5600^ K. will provide bluish tinted
photos, and a 2900^ K. lamp for a studio light will provide orangish tinted
photos that have no blues or violet colors.
The dual-contact linear filament form of tubular lamp envelope is made of
quartz glass, and those Tungsten-Quartz-Halogen lamps generally function
in the higher VA and higher light output ranges than the smaller lamps, for
example, those that have dichroic reflectors. The latter are derived from
T-H projector lamps, and the Dichroic reflector is designed to transmit
and not reflect infra-red light.
(All heat that is conducted in materials, or that is radiated, is infra-red light.
There is no such thing as "cold" in the universe - only IR light.)
One nice thing regarding the LV T-H lamps is that they can be economically
dimmed from 5500^ K. down to a dim glow.
Overall, the LV T-H lamps produce more light for a given amount of
electricity than ordinary lamps, however, the hardware and lamps are
more expensive. The fabulous variety of light fixtures for every need
is great. Many of them can be concealed in rows or provide many types
of special lighting effects.
110VAC T-H lamps use the conventional medium bases, and probably also,
mogul and candelabra, screw type bases, and sometimes have heavier
glass envelopes for HD applications. Otherwise they produce about the
same amount of light as the LV T-H lamps if operated at the same color
temperature. They produce more light for the electricity consumed than do
the conventional tungsten lamps. I think that at the same lower color
temperatures, say at 2800^ K., the Q-T-H studio lamps may outlast the
ordinary tungsten medium base studio lamps, and the Q-T-H lamps and the
sockets may be more expensive.
Okay.....
Ralph Hertle
******************************
Ralph Hertle
You provide some interesting information regarding
lamps and tungsten , and I agree.
Some more data is available on the site:
http://www.tungsten.com/mtstung.html .
It says the the Melting Point is 3410 ºC.
And .... on the Kelvin scale at:
http://antoine.fsu.umd.edu/chem/senese/101/measurement/faq/why-273.15-kelvin.shtml .
Thanks.
Ralph Hertle
""""""""""""""""""""""""""""""
AC/DCdude17 wrote:
> X-No-Archive: Yes
>
> Ralph Hertle wrote:
>
> > Ramman:
> >
> > Tungsten-Halogen lamps (e.g., 50V. or 120V.) produce more
> > visible light than ordinary light bulbs because they can be operated
> > at higher temperatures.
>
> Correct. Halogen lamps are slightly more efficient, because of slightly increased
> filament tempreature.
>
> > Ordinary lamps (light bulbs to us commoners) without the halogen
> > gas must be operated at a lower temperature. Alternatively, T-H lamps
> > are commonly operated at temperatures of up to 5500 deg. Kelvin. Ordinary
> > lamps that you get at the supermarket usually operate at 2900 deg. K. to
> > 3500 deg. K.
>
> You got the main idea, but your numbers are WAY OFF.
>
> normal tungsten halogen operates at 3,000K at most. Some projector lamps are very
> intense and operates at 3,400K, but only lasts about 50hrs. Halogen lamp can not
> operate at 5,500K, because it's melting point is 3,695K
>
> >
> >
> > The color of the light is different according to the temperature of the
> > tungsten filament. The Kelvin color temperature scale is used to provide
> > a scale of general color spectra ranging from the dull glow of (next to
> > infra-red heat and nearly invisible) red light at 1000 deg. K. of the heating
> > element of an electric range on up to the blue-white color of Solar daylight
> > at 5500 deg. K. The scale reaches lower and higher, however, ordinary
> > lighting doesn't fall within that greater range.
> >
> > Ordinary ultra-long lasting lamps are operated at 2900 deg. K.
>
> More like 2500-2700
>
> > and have
> > a decided yellow-orange-white light. They have zero violet, zero
> > cool blues, and less warmer blues.
>
> It contains very small amount of violet and cool blues. It is incorrect to say zero.
>
> >
>
> > They have a friendlier, warmer color at
> > 2900^ K.
>
> "friendlier" is a subjective term.
>
> > than the 5500^ K. color. The lamps last a long time, however, the
> > colors of certain fabric patterns, clothes, and works of art may look rather
> > bleak, old, and yellowish.
>
> You can't get 5,500K light out of a clear glass incandescent lamps, halogen or not.
> You'll have to use fluorescent lamps.
>
> > Color temperature is the general cast of light that seems to be the same
> > color as light emitted from a tungsten filament operated at a certain
> > temperature, and the color is measured in degrees Kelvin. A photographer's
> > light that has a lamp that operates at 5600^ K.
>
> They're either fluorescent or short-arc xenon discharge lamp.
David Combs
AC/DCdude17 <Je...@prontoREMOVETHISmail.com> wrote:
>X-No-Archive: Yes
>...
>
>FYI, it is called transformer, not ballast. Transformer simply decreases or
>increases voltage and is a constant voltage source. Ballast provides high
>enough voltage to initiate an arc in a discharge lamp and operates in constant
>current mode once the lamp is started.
Questions galore:
(I'm probably not the only one who has *some*
(remembered from *long* ago, half-likely incorrect)
knowledge of electricity, AC, inductors, capacitors,
transformers, etc.
Meaning that I and others like me have some
half-baked concepts in our heads, via which
we'd like things explained to us. So maybe
it isn't so useless for me to spew out all
this mind-garbage (or worse) -- by setting
"us" straight, "we" will learn a bunch,
correct our varous *ridiculous* ideas.)
:-)
I know what a textbook-type of transformer is:
just a correctly shaped piece of iron,
and two long wires, of *unequal* lengths,
so that when each is wrapped tightly around
opposite parts of the iron shape, one wrapping
has more wrap-arounds than the other, the
ratio of the two giving the voltage multiplicand
or divisor.
What I do *not* know is what a "ballast" is.
Yes, I've seen the things; when I had a bunch
of large fluorescent 4-bulb fixtures, each bulb
maybe 4 feet long. Fixtures pretty hefty.
Attached to the part of the fixture just behind
the bulbs (you could see it through the spaces
between the bulbs) was this foot-long black, uh,
"box", and all I know about it was that when it went
bad, oil would drip out. You take the thing off,
and it weighed maybe two, three pounds.
People *referred* to that black thing as the "ballast";
seemed to me to be heavy enough to also have a pretty
good transformer stuck in there too. Maybe *that*
was where the dripping oil originated from.
----
Now, I've told you *everything* I know about electrical
connections to the bulbs, but I have *no clue* as to
what the "ballast" is or does.
Although the name does seem to relate to an
inductance -- doesn't an inductance stay ready and able
to *attempt* to keep whatever current's running through it
*from changing*, via its magnetic field -- by diverting
energy from a rising current into the inductor's magnetic field,
and releasing it to a current that's falling.
Maybe my memory's been faithful, and I got that
right (else, won't be the first time I've been wrong!)
That keeping-things-from-changing *seems* like what
something called a "ballast" would do.
------
Idiotic question: doesn't the above exactly
describe one-half of a *transformer*?
Or does the fact that a transformer's trying
to *efficiently* transfer power from one wrapping
to the other pretty much negate the ballast action?
Or is the ballast-action actually what makes
a transformer *work*?
... and it gets used-up in getting the transform
to actually *work* (er, "function") (efficiently)
, and *that's* why you need *another*, third,
one, which is termed "ballast"?
----
Anyway, why does a fluorescent light *need* a
ballast?
AH HA! I've got it! (while writing this thing)
-- maybe:
You don't want
the thing *flickering* too much; it'd drive you
crazy, if it did. (Damn near does anyway. At
least, women I know *hate* the things!)
Now, if you stuck a big inductor in series with
the AC input, maybe you'd be getting a result
approaching *zero* current, as the inductor fights
that current changing so much it even switches
directions at every "cycle"!
Something I remember is a "diode" (when I learned
it, it was a vacuum tube) -- lose half the current,
but what you do get is at least all going in the
same direction. And so you drive your light with
that half, induced to be a bit smoother.
Or is that just as crackpot as all my other thoughts?
-----
Then, there's something called a "starter", a little
aluminum cylinder about an inch in diameter and
perhaps an inch and a half long.
And how does *that* help in starting a fluorscent light?
---
Thanks for whatever you can do to clear this up.
Maybe the result can end up in a faq named
"Ballasts for Victims of Alzheimer's"
David
David Combs
Ralph Hertle <ralph....@verizon.net> wrote:
>AC/DCdude17:
>
>You provide some interesting information regarding
>lamps and tungsten , and I agree.
>
>Some more data is available on the site:
>http://www.tungsten.com/mtstung.html .
>
>It says the the Melting Point is 3410 ºC.
>
>And .... on the Kelvin scale at:
>http://antoine.fsu.umd.edu/chem/senese/101/measurement/faq/why-273.15-kelvin.shtml .
>
>Thanks.
>
>Ralph Hertle
>
>""""""""""""""""""""""""""""""
I tried using google on "fluorscent ballast",
and all I got were places making and selling
the things -- nothing *explaining* them.
In general, what *are* some good "tutorial"
sites for the various things this thread
has been about. Anyone know of any?
Thanks!
David
v
Combs) wrote:
>I tried using google on "fluorscent ballast",
I hope you didn't spell it that way when you "toggled", and it is just
a typo on THIS post!
-v.
Sylvan Butler
> In general, what *are* some good "tutorial"
> sites for the various things this thread
> has been about. Anyone know of any?
I think there is only one worthy of note. Don Klipstein's:
http://misty.com/people/don/
--
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