1948 Spotlight=Deathtrap

[ship]

Carbon arc, a deathtrap??? not so. if vented, actually a very safe, reliable workhorse. State of the art for many years. I have run many different types from the small Troupers to the giant Genarcos with positive carbons 24" long and as big around as a broom stick. I worked as a Strong Repair technician for a while in the early '70's, so I do have a small appreciation of the workings of the carbon arc light.

Back in the stone age, when I was in grad school I did a paper on "The Development of the Carbon Arc in the 19th Century". Went from battery powered, carbon arc furnaces used for carbide production and steel smelting, street lights in Paris, to back stage flood lights and then to FOH theatrical spot lights. They of course played a major role in both the World Wars as air raid search lights and then for many years were the beams of light you saw in the sky at openings of new movies, special events and such. Between 1820 and 1885 over 200 patents were issued for mechanisms to regulate or feed the carbons as they burned. One of the more interesting, the Jablokoff Candle, relied on a marvelous, controversial new development, alternating current. In the "normal" DC current supplied by a battery or later by dynamo, the positive carbon will burn away at about twice the rate of the negative. the Jablokoff candle, used extensively in street lights in Paris, took two carbons, side by side/parallel, insulated by a thin layer of kaolin or china clay. The alternating current burned the two carbons at equal rate, making the Jablokoff candle self regulating.

The real Death Trap was what the carbon arc replaced, the Lime Light. The lime light was produced by focusing an Oxygen-Acetylene flame (welding gas) onto a block of lime. The lime when heated, incandessed, producing a very bright light and our present slang term to "be in the Lime Light". And that was the real "Death Trap." Metal cylinders for gas did not exist yet, nor did gauges or regulators. The gas was contained in skin bags and the operator sat on the bags to produce and maintain proper pressure to produce a good flame. Explosions and fires were not uncommon.

So, what was that you said about that finely crafted piece of antique machinery?? Deathtrap!!! Not So!!

Michael Powers, Project Manager
ETCP Certified Rigger - Theatre
Central Lighting & Equipment Inc.
675 NE 45th Place, Des Moines,

Thanks to the above... got handed a phone call today from someone while on beak... Ship's standing right here... (there must have been a problem on a show site..)

It's the 1980's calling about your blue jean jacket... got kicked upside the shin once I realized the joke on me in a good harted way.

Sometimes at work get joked about as old school or old and I am perhaps as compared to most I at times could be their dad of. Here I am advocating 400' ethernet wire six channel DMX and two channel Clear Com snakes for use, but still also holding onto the concept that the 360 or 360Q isn't a useless fixure. This much less beyond being the LED fab guy for many projects, I also specialize in antique fixtures or wiring. No I have no idea of how to work a modern light board or how to change a lamp on a fixture - could figure it out, but not my specilization. Instead me knowing how a strip light works is more useful at times with other older design concepts.

Anyway, thanks the above carbon arc operators for not making me feel as aged in experience in that while I wouldn't pass up such fixtures, I came to the industry at a time after them. This and with my own breadth of experience your own is none shorted in being also well experienced in a way so as to form an opinion. This as opposed to those po, pooing such things as ... Not S-4... how ancient, I cannot design with this crap. And we gotta have moving lights in our high school because if I at 16 years old and don't have experience with one after only say two years experience in the theater industry I'm missing out. Carbon arc... they are on my list to collect and learn.


By the way MPowers, given this was a Graduate School paper, it's no doubt worth publishing here for all to learn from and a perminant record of what you found. Any cance of you contacting the Webmaster Dave in having him place your paper somewhere say in an upcoming reference library for others to use and learn from in the future? ISU and Elmhurst college had a lot of books for me to learn from in the past, since than I have bought many of those books I learned from. Not all places have such librarys available and I don't know to what extent books at this point have been put on line. As with my 1916 Chicago Stage Lighting catalogue that's now at least out there and available, any chance on your own paper becoming available as with others in high level research on subects?

 

[MPowers]

To be honest, I don't know if a copy of the paper still exists. Wen it was written, there was no such thing as a PC. Everything was hard copy. I'll take a look and see.

Michael Powers, Project Manager
ETCP Certified Rigger - Theatre
Central Lighting & Equipment Inc.
675 NE 45th Place, Des Moines, Iowa, 50313

 

[Scarrgo]

ran my first trouper in 75 or 76, had to stand on an apple crate to run it. we even had a lobsterscope and a UV filter for blacklight, ahhh the fun. And gloves? no way, we used a washcloth (dry) to pull the burnt rods out....no douser, fades we just pulled the rods apart, re-strike, and should'nt take more than 45 sec for carbon change. I never got used to the taste.

Still take a carbon over a lamp any day

Sean...

 

[MPowers]

Pull the rods apart? You've gotta be kidding! That would give you a brown out look and a snap off at the arc break point. Any good trouper opp knows the best fade is a trombone/iris fade. pull the trombone back slowly to full flood while at the same time irising down with the other hand to maintain the same size spot and the color temp stays the same all the way through, tap the gillotine at the last moment to kill the bleed. Oh yeah, with the "other" hand continue following the dancer as they exit. The Strong line, Troupers, Super Troupers, Gladiators, worked best but any carbon arc could match the dimming curve of the house dimmers with a decent operator.

Michael Powers, Project Manager
ETCP Certified Rigger - Theatre
Central Lighting & Equipment Inc.
Central Lighting & Equipment

 

[CrisCole]

Uh oh, you done opened a can 'o worms here -


I have a feeling that the "no joke" prefix was unnecessary as
several of our most active and knowledgeable members [EDIT: except Ship ] grew up on carbon arcs and this is gonna make them feel ANCIENT!

Sounds like the venting is inadequate or non-existent. Is there a dryer duct looking pipe coming from the top of the unit and hopefully through the ceiling? Sure hope so... And I don't think there should be any time when you should not run the exhaust fan on this if used indoors, but then again, I didn't learn on a carbon arc, nor have I ever personally used one.

Seems like I heard somewhere that the use of these has been banned in several states.

Oh, well indeed, I didn't realize that...I'm rather new in the buisness and, though I've read about these monsters, I've never seen one.

The venting was the issue-that's why it was a deathtrap. The extent of the venting was some dryer ducting that went from the spotlight to the floor. Not out of the booth, but in it. The light was literally piping carbon monoxide into the light booth. But hey, they though it was okay, because they had a open window and a box fan...

No wonder everyone was so drowsy after they were done with a show!

I think the OP was stating that he felt as though the followspot was a deathtrap?

Running a Carbon Arc followspot is quite fun. it sounds like an old trouper (they didn't have an automatic carbon feeder motor). it took skill to keep everything going and still operate a seemless show. the old timers will all have stories about Caron Arc followspots. post some photos. if there is still a carbon arc followspot there, you should look around...they may also have an old carbon arc movie projector as well.

There isn't a movie projector, but after some fishing, I found a old 'Batman' style searchlight, with the same Carbon Arc setup...wow!

Carbon arc, a deathtrap??? not so. if vented, actually a very safe, reliable workhorse. State of the art for many years. I have run many different types from the small Troupers to the giant Genarcos with positive carbons 24" long and as big around as a broom stick. I worked as a Strong Repair technician for a while in the early '70's, so I do have a small appreciation of the workings of the carbon arc light.

Back in the stone age, when I was in grad school I did a paper on "The Development of the Carbon Arc in the 19th Century". Went from battery powered, carbon arc furnaces used for carbide production and steel smelting, street lights in Paris, to back stage flood lights and then to FOH theatrical spot lights. They of course played a major role in both the World Wars as air raid search lights and then for many years were the beams of light you saw in the sky at openings of new movies, special events and such. Between 1820 and 1885 over 200 patents were issued for mechanisms to regulate or feed the carbons as they burned. One of the more interesting, the Jablokoff Candle, relied on a marvelous, controversial new development, alternating current. In the "normal" DC current supplied by a battery or later by dynamo, the positive carbon will burn away at about twice the rate of the negative. the Jablokoff candle, used extensively in street lights in Paris, took two carbons, side by side/parallel, insulated by a thin layer of kaolin or china clay. The alternating current burned the two carbons at equal rate, making the Jablokoff candle self regulating.

The real Death Trap was what the carbon arc replaced, the Lime Light. The lime light was produced by focusing an Oxygen-Acetylene flame (welding gas) onto a block of lime. The lime when heated, incandessed, producing a very bright light and our present slang term to "be in the Lime Light". And that was the real "Death Trap." Metal cylinders for gas did not exist yet, nor did gauges or regulators. The gas was contained in skin bags and the operator sat on the bags to produce and maintain proper pressure to produce a good flame. Explosions and fires were not uncommon.

So, what was that you said about that finely crafted piece of antique machinery?? Deathtrap!!! Not So!!

Michael Powers, Project Manager
ETCP Certified Rigger - Theatre
Central Lighting & Equipment Inc.
675 NE 45th Place, Des Moines,

And I agree...now. My immedate reaction to seeing this thing in it's current condition was, "HOLY CRAP! They are still legal? It's not even ventialated!"

Turns out that there is a special hole in the ceiling that the ducting should have been leading to. But some janitor decided to fill it full of caulking and rags (don't ask me why, I will never understand it) and the ducting laid on the floor under neath the spot. Literally piping in Carbon Monoxide. But it was okay, because they had a window open in the booth. I'm suprised people haven't died!! And it's at a school!! A Jr. High-they really have kids running it all the time...

I removed all the caulk (boy that was sooo much fun ) and replaced the ducting. Now I feel better about it.

I really am suprised that these things are still in use, and legal... though I can see they are not as bad as the Lime Lights, they still are not as bright (at least in mine's state, even though we polished all the mirrors) and, IMO, safe as newer followspots.

But what I can't understand, is that they have a 5 year old followspot sitting up in the catwalk, and it's never used...instead, they use the Carbon Arc followspot...
Isn't there some museum or collector that would buy it?

I'll see if I can snap some pictures next time I'm there.

 

[Les]

Actually, the problem is more of one with ozone. Carbons usually "burn" at a high enough temperature that if fully oxidizes to CO2 and not CO. Of course there is always the copper burning off the rods producing all sorts of sulfates which give it that wonderful metallic smell!

Ozone can damage your lungs so arc lights kind of got banned. They still have a warm spot in many of the hearts of some of us "old-timers."

Deathtrap? No, that's usually the meal before the gig.

OP, are you sure carbon monoxide (CO) is being 'piped' into the booth?

Personally - I have no idea, but this post by JD gives me the impression that CO is not the primary concern or reason for the ducting. And hopefully that pipe that you de-caulked still vents to the roof, and has the appropriate weather cap. Otherwise, you could be venting whatever hot gasses right in to the attic. There may have been a reason they sealed the hole - you might want to find out why.

 

[JD]

Since the venting works by convection, I doubt the pipe on the floor was putting out much of anything. Probably just backing up and seeping out of every hole in the lamphouse. (Fan will disrupt the arc and may crack the mirror.) Not much CO, but that white ash contains lye and copper sulfate, (and, of course the ozone) so breathing it in is generally not a good idea! (Must admit, I can't remember ever running one with a vent pipe, but was usually outdoors or in a non-confined space.)

Regarding the brightness issue, A well running Trouper puts out a bit less then what a Satellite does, and a Super Trouper is quite bright even by today's standards. If it is a Trouper, push the red handle all the way forward. (The Trombone!) Try irising out, and if you can not get wide enough, then pull the handle back a bit. The output plummets as you pull it back, but it gives you a wider flood.

If it is not a Trouper, it may still use "zoom" optics and have the same effect.

 

[CrisCole]

OP, are you sure carbon monoxide (CO) is being 'piped' into the booth?

Personally - I have no idea, but this post by JD gives me the impression that CO is not the primary concern or reason for the ducting. And hopefully that pipe that you de-caulked still vents to the roof, and has the appropriate weather cap. Otherwise, you could be venting whatever hot gasses right in to the attic. There may have been a reason they sealed the hole - you might want to find out why.

No, the vent does lead to the ceiling. I'm not sure what you mean by weather cap, but it does have some black flip lid looking thing on it...

Whether it was CO or CO2 or whatever, it still was something I wouldn't want to be breathing in in a confined space.

Here's some photos. I don't know much about them, but I hope it helps.

 

[CrisCole]

Sorry to double post, but here are some more pics.

 

[CrisCole]

 

[JD]

Yup, it's a Trouper! Older,Smaller brother of the Super Trouper. Uses 6mm AC carbons and is a darn good workhorse. Cut sheet- The Strong Trouper

Company that built it - Strong Entertainment Lighting » About Us

They still have the owner / operation manual on the site! They don't direct link, but here's how to get there-
Go to the site above
Click "Resource Center" and select "Strong Followspots."
Select "Trouper Family"
Select "Trouper 4800"
Select "Instruction Manual"
Click "Trouper 48000-7"

There it is! Save the PDF, you may need it. Carbons should autofeed on this unit.

Should be giving you 180 fc at 100 feet, a decent amount of light!
Owned two of them back in the 1970's

One last thing, there was a third party building Xenon conversion kits for them! That would make it kick butt! I think Derek posted the cut sheet on that once. Might be nice if you could find one of those in someone's bone yard.

 

[Scarrgo]

Wow, it still has the glass drip guard, and its pretty clean inside.

Nice looking lights...
Sean...

 

[mstaylor]

The trouper was always so much easier to use, same rods front and back. Judging by the pictures there is no reason it shouldn't be putting out a very bright light, a little blue but a good strong light.
I never ran a batman style search light but I have been around them many times, talk about some huge rods!

 

[CrisCole]

It's light isn't bad, but compared to the new Lycian we have, it's light isn't hardly visible.

That's what I can't understand. They have a great spot sitting in the attic, but won't get rid of this thing and put the newer spot in its place.

 

[JD]

Lycian makes a lot of different spots. A comparable one would be the 1209 which is an HMI discharge spot that puts 145 fc on stage at a 100 foot throw. The trouper will put 180 fc so it is a bit brighter. If your Lycian is a 1209, then something is very wrong on the trouper. (Check the zoom lens system.)

Now if it's a 1266 (Super-arc 400), then it should beat out the trouper by landing 256 fc on the stage.

They make a lot bigger ones that will blow the trouper away for sure. Here is the run down-
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