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Marko

Mon Nov 20 2006, 09:02PM

Registered Member #89 Joined: Thu Feb 09 2006, 02:40PM
Location: Zadar, Croatia
Posts: 3145

Steve: you could strike them up relatvely easily, using some kind of pilot transformer, hooked up in series with tube and 12V source (there was and arc cuttger project on this site using similar design).

OR maybe you could just ionize them externally with a TC or something.

Regarding cooling, it shouldn't be some great trouble since power is just 120W (dunno for chris's tubes; but they look pretty

)

Chris

Mon Nov 20 2006, 11:06PM

Registered Member #8 Joined: Thu Feb 02 2006, 04:34AM
Location: Harlowton, MT, United States
Posts: 214

Both these lamps require a 30kV strike voltage, and around 100V no-load DC voltage for the arc to develop properly. They require forced air cooling. The DC operating voltage and current for the large one (4500W) is 32V 135A and the small one (2kW) is 24V 80A, both at like 2% ripple. It's definately a job for a serious and well regulated power supply, otherwise BOOM. I was going to use my alternator set to accomplish this, but haven't got around to it yet and have other projects. I did build a good heavy lamphouse for them though. They contain about 30atm (440psi) hot and 10atm cold, and operate at such temperature that they need a special graded and folded seal to join the quartz envelope in several stages to the electrodes to allow for the difference in thermal expansion. The smaller one is the exact same type we used at the theatre when I was a projectionist there, and that's how I got interested in them. That type retails for around $1000 while the larger one retails for $2500. I got them on ebay for much less of course, the 2kW lamp is brand new and the 4500W one has 500 hours on it, but seems to be in remarkable condition for that much use. You definately wouldn't want to run one in the open, not only because of the potential explosion hazard, but they would really burn your eyes almost immediately if you viewed the arc. The big one puts out 190,000 lumens from a 6mm gap

so it doesn't leave much to the imagination. They put out a great deal of UV, and mercury ones do even far more. I want to make a huge spotlight with it, just for fun. If I get a pic of the arc I'll post it here.

Edit:
I always thought this frame of one of my test rocket engines was interesting. The exhaust makes a toroid thingo when it hits the ground.

ragnar

Thu Nov 23 2006, 03:15AM

Registered Member #63 Joined: Thu Feb 09 2006, 06:18AM
Location:
Posts: 1425

Not one, but *gasp* five cool pics. =)

Aw, why not six, seven, eight, nine.

[Edit: Avoid double-posting (FYI: double posting is posting twice in a row in a thread, without allowing any replies in between). Double posting just to get a topic marked as new is a no-no. Every topic deserves a chance. If yours slips into obscurity, its chance came and went. If 48 hours have elapsed, and you have some new information to add, you may double post. This is the only exception, there are no other exceptions!]

Chris

Mon Dec 18 2006, 10:35AM

Registered Member #8 Joined: Thu Feb 02 2006, 04:34AM
Location: Harlowton, MT, United States
Posts: 214

It's probably not too difficult for most of you to guess what these pics are of. Anyway, I thought they looked cool. Enjoy.

The lamp is fully warmed up for all these pics, I just played around with the exposure time.

Tesladownunder

Thu Dec 21 2006, 01:10PM

Registered Member #10 Joined: Thu Feb 02 2006, 09:45AM
Location: Bunbury, Australia
Posts: 1424

It looks a bit like this doesn't it

Peter

...

Thu Dec 21 2006, 03:05PM

Registered Member #56 Joined: Thu Feb 09 2006, 05:02AM
Location: Southern Califorina, USA
Posts: 2445

Except that it is actualy yellow (I am guessing that you were looking through a pair of welding googles?) and about a million times as bright

Chris

Thu Dec 21 2006, 06:43PM

Registered Member #8 Joined: Thu Feb 02 2006, 04:34AM
Location: Harlowton, MT, United States
Posts: 214

Yeah, it's a 1500W metal halide lamp. Really bright at about 6000K color temp (white). I was definately looking through a welding lens.

ragnar

Sat Dec 30 2006, 04:33AM

Registered Member #63 Joined: Thu Feb 09 2006, 06:18AM
Location:
Posts: 1425

Headroom?

Dr. Drone

Tue Jan 02 2007, 05:10PM

Registered Member #290 Joined: Mon Mar 06 2006, 08:24PM
Location:
Posts: 1673

Steve Conner

Tue Jan 02 2007, 11:00PM

Registered Member #30 Joined: Fri Feb 03 2006, 10:52AM
Location: Glasgow, Scotland
Posts: 6706

It sure is cool

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