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Gringo · 11-11-2011, 07:59 PM

Won't that thing push a starship if you point it backwards?

I guess you could jacklight deer without firing a shot. Medium rare.

Buttercup · 11-11-2011, 10:48 PM

No, I don't have the amperage wrong at all. A short arc tube like this will draw far more current if given the opportunity. But the ballast ensures that it draws just enough to sustain the arc. Short arc bulbs are unlike incandescent lamps who's resistance goes up as the element heats up. Once ignited, a short arc bulb will draw current easily as it has such a low impedance.
So, the current to the bulb is clamped to prevent a runaway as it were. Also, 28 volts at 58 amps (or was it 52 amps, I don't remember exactly but it is in the tech manual I linked earlier) is not the bulb current, but the total current of the entire lamp assembly which includes cooling blowers and the igniter circuit and whatnot. The bulb alone should draw somewhere in the vicinity of about 35 amps if the supplied voltage to it is indeed 28 volts. The rest is overhead.
Now, with a series bank of batteries and an appropriate charger and with intermittent use, one EU2000 could power the whole thing. I classify intermittent as perhaps a 50% duty cycle for the lamp - 15 minutes on, 15 minutes off. When the lamp is off, the cooling blowers still operate but they are only a few amps, allowing the generator to recharge the batteries. I calculated the total DC draw at approx 1670 watts, which is within the continuous capability of an EU2000.
The batteries - when and if I get them, are capable of a 75 amp draw for up to 115 minutes - of course, at that draw without charging, the overall supplied voltage of the battery bank will likely drop below the minimum required voltage specified for the lamp which is 22 volts.

Quote:

Originally Posted by Eric H

If it's a 1 KW bulb it will only draw between 10 and 20 amps tops...
SEE HERE: Convert 1 KiloWatt to Amperes
I think you have the amps wrong, 58 amps is about 1/4 of what comes into most houses, that's why it takes that much to power a 12K (which will make nighttime daytime:-)
Take a look, it takes two of the honda generators to make 30 amps (at 120)..
Reliance 30 Amp RV Parallel Kit for Honda EU2000i, Model# HPK2011 | Generator Accessories | Northern Tool + Equipment
This is something my crew struggles with day in and day out during location shooting... one 20 amp circuit will just handle a 2KW light (tungstan, so ACTUAL 2000 watt draw).
So you're batteries might power the light you have, but your batteries are not even close to 58 amps...which is a fun and dangerous amount of of amps.

Buttercup · 11-12-2011, 05:16 PM

Here is the ballast resistor. It is located at the outlet of the heat exchanger. Air from the heat exchanger blows across it, cooling it.

Here is an interior view looking at the back cover which houses the ballast, blowers and heat exchanger.

And lastly, the insides which show the cooling air inlet to the bulb and the frameworks for the mirror, etc. Buried inside the frame is the igniter and other circuits.

I don't need to tell you just how well this thing is built! Can't wait to fire it up!!!!!!

perryg114 · 11-12-2011, 06:42 PM

Just be careful with that thing. Those bulbs are made of quartz so you don't want to touch them with your fingers and there is like 7 or 8 atmospheres of pressure in it. It is a BOMB. I have used them in UV souces and solar simulators. I never had one of the 1000-2500W bulbs blow but I did have a small one blow one time and it was like a gun went off. I have heard stories of them blowing up and sending the lamp housing across the room. These same type bulbs are used in movie projectors.

Perry

Buttercup · 11-12-2011, 07:22 PM

Quote:

Originally Posted by perryg114

Just be careful with that thing. Those bulbs are made of quartz so you don't want to touch them with your fingers and there is like 7 or 8 atmospheres of pressure in it. It is a BOMB. I have used them in UV souces and solar simulators. I never had one of the 1000-2500W bulbs blow but I did have a small one blow one time and it was like a gun went off. I have heard stories of them blowing up and sending the lamp housing across the room. These same type bulbs are used in movie projectors.

Perry

Oh yea - before I ever bought this, I saw a video of a guy who simply picked up one of these bulbs and it exploded - just exploded. The guy had no face shield (which I have) so he took a face full of glass. I don't know if he was hurt or not. The tech manual explains exactly how to handle the lamp but I have no need or desire at t5his time to remove that bulb. Heck, I have to see if it will even fire up or not.

Eric H · 11-12-2011, 10:37 PM

Amps = Watts/Volts...
so coming off the generator at 120 volts (since thats what it puts out): 1670 watts / 120 volts = 13.9166667 amps

If those generators can also do 240 volts then you'll be looking at half that many watts.

Yes, an arc light will continue to draw power until it explodes if it's able to, but that's not the issue here. You have a 1KW light, adding in the other wattage it's using you have a draw those honda generators can handle it, those generators just don't put that many amps out.. but you won't need that many amps... you'll only need 13 amps. Now off a 28 volt battery system you will use that man amps... Just saying, you have a sweet light that you can power from a suitcase generator (or batts).... it'll be sweet.

perryg114 · 11-13-2011, 05:29 AM

The power supplies for these things are boat anchors and they weight about 100lb. Ours ran off 220V. THey were big DC power supplies about the size of a welding power supplies. Ours were made by Oriel. I would pucker when I had to change out bulbs. They are most dangerous when they are hot.

Perry

Buttercup · 11-13-2011, 05:55 AM

I am getting a telecom switchmode rectifier that will do at least 65 amps @ 28 volts, give or take. This will be to charge the batteries and run the lamp as needed. This supply weighs maybe 20 pounds. The batteries of course will weigh more.

I am quite hopeful that this light was maintained well and that the bulb is fairly new with little hours on it if any.

Smokin Camel · 11-13-2011, 08:40 AM

Quote:

Originally Posted by doug&maggie

It's quite lovely, Buttercup!

I want to see it in use.

Maggie

This ranks right up with the periscope idea

Buttercup · 12-28-2011, 09:11 PM

Well, after searching locally and coming up empty handed, I finally ordered a plug connector online and got a "DEAL" on it - if you can call it that. $126 and free shipping to boot! Who could ask for more...

Also, I pulled out my 24 volt, 100 amp Swichmode Rectifier that Santa got me for Christmas (how did he know?!?) I'll need to do some configuration work before I can fire it up. I have a 2kva step-up transformer that I can use to power it in remote situations and in my garage, I have a 220 volt outlet to feed it for test.

I feel I am just a few weeks away from First Light!!!! And some prized Beam Shots and maybe even a visit form the local police if I am lucky!

CAN'T WAIT!!!!!!