Arc Lamp Question

There should be a minimum and maximum gap between the electrodes for which the system was designed. You can actually find out what the absolute maximum can be through experimentation. Start with electrodes separated as far as possible and hit the igniter. If an arc doesn't start, move them a little closer.

The purpose for the igniter is to provide an ionized path of air (via a high voltage spark) for much higher currents to flow at much lower voltages. It's similar to touching an arc welding rod to the surface of the work and withdrawing the rod to an appropriate distance. For an arc lamp, however, such action is not hand-operated as the electrodes must be moved toward each other in time to compensate for the burning away of the electrodes, so there's more than likely a screw mechanism to do this function.

I have seen arc lamps which don't use an igniter but rather a piece of sheet metal that is passed between the ends of the electrodes making an electrical path from which an arc is started and maintained. With the power off, the sheet metal is used as a gauge to set the "ideal" distance between electrodes.

Old machines used time, type of electrode (there are various carbon composition electrodes which burn away at different rates), and a variable speed DC motor connected to a screw mechanism to maintain the distance between them. Newer machines use either constant arc voltage or constant arc current to control the distance.

This is very wonderful answer, detail very much. I remember it is. I touched the lamp very years ago when we had a project in my workshop, 35mm project, large one, not portable one. it use arc lamp in order that can project strange lightning to screen. sometimes I was inteested in operating it. when the automatic starting part has something wrong I have to operat as same as above description. The power is supplied by a magnetic saturation stabilizer which can send out a hv instantly by a capacitor and inductor transformer which together produce an attanual osc and the transformer second get a hv to toggle the arc , after the carbon rob is burned, the current will go stable and the rob move automaticly on the swirl spin system(secrw system) to keep a little gap about 3-6mm (I remember) or more a little. now we hvnt seen it but instead of xenon lamp. it has linear spectrum, not as continuous spectrum as cabon rob burning, but very approch solar spectrum and can get good showing color. but some of them has a little lower color temperature. this lamp has many advertages than cabon rob, especially for health and envirument. Why are you still using this type lamp? what are you use it for? (sorry to ask these question)

For both cnpower and coffeebean,

These are sealed mercury vapor tubes, about 10 inches long. Also, going to be using krypton arc lamps. They're for continuous pumping of a laser device. BZZZZZZT!!!

Thanks, guys! I do wonder if the igniter stays in the circuit, and just goes passive. Any ideas?

Just for the hell of it, this arc lamp. What do you gonna use it for?

Usually the igniter is called a tickler. The ballast that adjusts the voltage is what you call the power supply. It provides reactance to limit the current otherwise the short circuit of the arc would lead to the voltage dropping below the arc maintenance voltage and it would go out. Often the afterglow allows it to restart very quickly, but your light has a sawtooth amplitude modulation on it.

When I used these in 1964 (older tech, I am sure), the igniter went from one terminal at the end (common minus) to the tube middle with a fine wire(tickler). When the igniter was punched and the voltage was on it created a small ionization within the tube which quickly avalanched to full brightness.

Let me see if I can search something specific, as my knowedge is very dated

ebay

with book, might make you a copy for a fee??

http://cgi.ebay.com/ORIEL-ARC-LAMP-SYSTEM-POWER-SUPPLY-HOUSING-MORE_W0QQitemZ200040945308QQcategoryZ42884QQcmdZViewItem

If you do get it going look out because you will get a very bright light and loads of dangerous UV make sure you take safety precautions. Also keep well away from any fire risk. The voltages before you strike the arc can be lethal make sure the insulation is still good. The arc will radiate RF interference as well. Take care.

Thanks for the advise!

the igniter is not needed once the arc is struck

Right, but does the igniter stay in the circuit as in my diagram? So does it just become a passive element after the arc is started?

the igniter can probably stay in circuit as it will be a high impedance path and will share common ground so it will divert very little current.

I had hoped you would approach the ebay seller and ask them for a copy of the manual for a few $$. SInce it s free $$ them might do it. The maker might also have a support page with a manual on it.

It's been my experience that user manuals are very rare on eBay. Seems like the first thing to go in the trash. If they exist, they usually come with the device as an extra selling point.

I've tried Oriel (now Newport) but my stuff is just a little old, but thanks for the advice and ideas! Much appreciated.

Carbon arcs actually produce a near-flat spectrum all the way to some residual lower gamma. way above UV. Some welding arcs do that too.