carbon arc = true white light

[Reid]

Edit, Nov. 2: new video

See the flame
http://www.youtube.com/watch?v=Hi7uifnYFvQ

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Many of you will know about arc lights already. But not the general public, no!
I'd never had one before so I bought the device from ebay last month.

Here is the YouTube video made of the thing the other day.
















Carbon arc light is interesting on a number of counts.
This unit, of course, was made for sun-therapy, not area lighting.

We all know too that the naked arc outputs UV and more, much more--right up into the RF spectrum.
It also outputs dust (clay binder?) and carbon monoxide.

Experiment to come: I have an old surplus tank periscope prism. Maybe I can get a picture of the spectral diffraction of the carbon light.

Need more plain carbons soon, and probably new retinas if I'm not careful.

Please check out the video and gimme a comment or rating if convenient?

Show or tell about your carbon arc lights experience or questions, etc. Thanks.

At shut-off:

 

[Trashman]

How much was it?

Someone will probably come by and let you know that your pictures need to be resized a tad, BTW. (small enough so most people don't need to move the scroll bar to see the whole page (which is dictated by the size of your pictures)

 

[Reid]

Thanks, T man. I've just resized them a notch smaller.

Cost? I thought it was $100...no, my memory was bad when I started this posting

Edit:

OK, here's how it went,
I just found the link to the auction I won.

Canadian seller first listed the item with a starting bid of $100.
There were no takers. Am pretty sure no-one else who looked at "room heaters" knew what it really was.

I wrote him to ask him if he'd be re-listing.

"Yes" And with a starting bid of $25.

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=330167677659

And as it turned out I was the only bidder. Shipping was also $25. Total cost: $50

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I'd like to learn more about the maker. The seller cited the online museum, Artifacts Canada, as his info source.
I don't yet find anything about the lamp there.

The seller did not recognize that it is a sun-therapy lamp.
Sure, it would work as a room heater---though pretty poor at projecting IR

seller's auction picture:


The "switch" (turn knob on the back) which the seller speaks about, is not for his stated reason to choose between heat and light:
no, it's there to strike an arc or cut it off.

Imagine using it as a heater aimed at your infant in its crib.
You walk away for a half hour, come back, and due to the carbon contact degrading by nature because it is not a pressed contact,
it could go into arc mode at any time. You could find your child burned and its eyes blinded by UV flashburn.


seller's auction picture:


The purpose of resistance in an arc lamp circuit, folks, is to limit the current to a workable level.
Without resistance an arc will draw almost fantastic amounts of power. Even as this is, about 1200W
the carbon tips glow orange as the video shows.

I'm going to make another run of the lamp for light output evaluation now.
Will report more fun stuff later. I hope!

Cheers,
Reid

 

[Reid]

http://www.youtube.com/watch?v=NQQMK1Rvq0A
​

what happens without current limitation
​

 

[Trashman]

So, how bright does it get?

 

[Reid]

So, how bright does it get?

Did a rough run in a bare room that has a white wall. Set the lamp about six feet from the wall.
I let it run for more than five minutes before manually cutting it off.

Bear in mind that it's an unfocused, point-source of light. And this V configuration of manually-set carbons cannot make a steady light for long.

Presuming it drops about 90V at about ten amps, that's about 900W of guesstimated power.

How much light? Looking at the white wall, illumination and color varies as the flame crater often shifts.
When it's wandering, or narrow, the light sometimes goes a bit toward yellow.

When the erosion takes the gap wider the light gets slightly blue-white; light output increases greatly.
and I'd say I see about the equivalent of more than 1KW of halogen incandescent power and with higher color temperature.

It's almost meaningless for me to guess like that--the source being in a deep bowl, and taking into account subjectiveness.
But, say you had the carbon points free-mounted, unenclosed, in a high white ceiling area.
I think then you'd have a good sized room lit up seemingly by broad daylight.

The color of the arc at close gap and small flame crater is yellowish at times,
and why is that? Must be because the lower temperature merely incandesces some of the carbon particles--like does a candle flame.

At higher plasma levels the carbon motes are more nearly consumed, and like with an acetylene torch, the carbon glows white to blue-hot

Here's a handy wiki page for general carbon arc info.
http://en.wikipedia.org/wiki/Arc_lamp#Carbon_arc_lamp
Zenon arc supplanted carbon arc for movie projection.
But I've read that zenon arc does not offer the same full spectrum, as does the old open air carbon flame.

Fun stuff. I'll try and make a viddy of the white wall soon.
The carbon rods are seen in silhouette on the wall,
and you can sort of see the flame kernel, see where it's moving,
and when it's at maximum diameter, all you see is a blazing bright white-out

And the sound of the unstable arc. And the smoke! It's :naughty: great!

zzz....ztspllzzzzzt!

________________

addendum:
Check this page out
http://ancientskyscraper.com/
Larry Radka is an amazing thinker

ancient lights and philosophers and stones and arcs...

 

[scott.cr]

Ahhhh very interesting post, very interesting indeed. I see, so the wire coils are like high-power resistors?

You gotta love the ignorance of auction site junk dealers. My side-collection (by that I mean "to the side" of flashlights) are Geiger counters. The dealers are eBay are either totally dumb, or lying through their teeth in their descriptions of the equipment.

I guess that can be a good thing too, such as when finding a carbon arc lamp for 50 bucks!!

 

[DM51]

zzz....ztspllzzzzzt!

Lol, is that what happens if you leave the bug screen off the front and a bug flies into the arc?

Great find!

 

[James S]

I"m so conditioned that I actually had trouble looking directly at the arc even on the video My eyes kept telling me to look away!

 

[Reid]

I"m so conditioned that I actually had trouble looking directly at the arc even on the video My eyes kept telling me to look away!

Oh yeah. I recall shipboard days. Welders could be working almost anywhere aboard. They never gave warning of striking an arc.
Several times I got caught by the flash while walking through a compartment.
Flashburn = misery for a day.

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[Reid]

Lol, is that what happens if you leave the bug screen off the front and a bug flies into the arc?

Great find!

:twothumbs

Larry Radka (at the link) is a collector of these things. Maybe he's a guy to ask to see of he has anything for sale.

But it would very easy to make a functional arc on this plan of one fixed and one rotating carbon. Much easier than an end-to-end arrangement.

I have a ca. 1911 Edison Home Kinetoscope.
I don't have carbons nor the original, external ballast.
I'll get a picture or two of the lamp workings up here soon.

If anyone here knows of any other arc lamps or videos, put up your links?

 

[Reid]

Ahhhh very interesting post, very interesting indeed. I see, so the wire coils are like high-power resistors?

You gotta love the ignorance of auction site junk dealers. My side-collection (by that I mean "to the side" of flashlights) are Geiger counters. The dealers are eBay are either totally dumb, or lying through their teeth in their descriptions of the equipment.

I guess that can be a good thing too, such as when finding a carbon arc lamp for 50 bucks!!

Yeah, that was a lucky break. Makes up for all the burns I've gotten in other ebuys.

Resistance: the resistance wire is best divided, half in series with each carbon, when operating with AC current.

The resistance is analogous to a fixed restriction, say, in a garden hose.
Without resistance we'd have a big pop and the circuit breaker would blow.

So, for a nominally 400W arc, you'd use sufficient resistance so that when the circuit is complete (carbons pressed together) you'd have a 400W draw.
Due to the arc resistance the actual power level will be much less I suppose.

This resistance could be afforded by a light bulbs in series with each of the two AC leads.
Carbon rods can be salvaged from old fashioned zinc chloride "D" cells.

It would be fun to lash up a home made arc lamp this way, eh?
It'd be a blast to pole-mount one out of doors and make a "street light" effect to learn how our 19th century ancestors
first experienced the electric light. Lemme find some illustrations.

Somewhere in my collection of ancient Scientific American magazines, in 1881, I think, is a report of the first portable night street lighting,
from Germany, by Siemens, for the purpose of enabling street repairs to be done at nighttime. It was a steam engine and dynamo on a wagon.
An extendable mast on the wagon was cranked up to elevate the globe-protected, automatically-fed carbon arc light about twenty feet in the air.
The reporter says that the light so-afforded was equal to broad daylight for workmen in the vicinity. Dig, lay pipes, patch pavement,
all during the no-traffic hours.


Everyone will remember, please, beware of flash burn to the eyes.
It only takes a second of direct view to make you feel a couple hours later like sand has been rubbed in your eyes.

 

[Reid]

New video


See the Flame
http://www.youtube.com/watch?v=Hi7uifnYFvQ
(click lower right corner of the player window to view in full screen)

The camera ISO was set to 50 and the exposure value set to minimum.

The lamp lights the room, sure, but this is stopped down so you can see that carbon arc is really a combustion process, just as (in essence) in any other flame
(so it seems to me; corrections appreciated).

The products are ash, CO and CO2. Note the yellow fringing at the top: partially burned carbon motes cooling to a yellow heat (candle heat).

Posited: the ultraviolet is there of course; you see it distorting the CCD of the camera in a vertical streak.

In the visible spectrum there's the full mix of all colors, plus a surfeit of yellow noticeable in the room lighting when the flame is small to moderate.

When the flame is at maximum (carbons drawn apart), the subjective color of light is white, tending toward the blue.

I'll make another short vid soon showing the silhouette of the carbons projected on the white wall.


r.