Flashlamp Video

[Draco]

I am going to use a commercial lamp that i have now to help me get a triggering system that reliably works then i will experiment with the home made lamps, i have two quartz tubes the exact size that you recommended to start from, I now have a drill press that has some of the features i need to use with brass, i still need a cutting insert and that may happen this week for that, i need to bolt the press vice down as well, i am hoping that will work, the cheapest metal lathe i have seen so far is about 550 dolor's, for a table top one and i cant afford that. I have a fried that works at a machine shop so if i butcher the brass i can have him make them.
I looked in my shed and found a 100k at 225 watts. i dont know if that's the current draw i want though. What values do you use? The 225 watt one is the highest value in ohms in a power resistor, all my other ones are 2.5 k and lower, and as my luck goes i accidentally knocked over a bin full of vacuum tubes, that's- a mess even though most survived
my vacuum pump should be ready for the task, it's vacuum "idiot lights" no longer function and Omega is useless for help but it will still get a deep enough vacuum to make "plasma in a jar" i don't remember what that is in Torr, the pump is a direct drive single stage omega fpuv91 i cant find anything on it. I have a dual stage one as well that was for HVAC I got it "kit form", it had a bad motor start cap and the moron took the vacuum section apart, so for a 10cm long lamp i am thinking the single stage will be fine, i still need valves and the tubing

[planters]

What do you want the resistor for? If it is to bleed then 1Mohm is in the range. That will "waste" at most 15W and should make your caps safe quickly. If it is to dump then both your 100K resistors should be able to handle the occasional one time load.

Your shed seems to have a lot of clumsy folks wandering through it.
Your single stage should be fine if it is able to allow a plasma in a sealed container. If it is not enough then wire your caps into a doubler circuit for charging and discharge them in series for twice the potential through the lamp.

I would skip the lathe. Get some brass rod approximately the same OD as whatever lamp tube you will use. Mount it in your vise and drill a hole in its center, part way through. Drill a small hole parallel to this main hole, lateral to it and all the way through from one flat face of the brass cylinder (rod) to the other. Pick up a tungsten welding rod, The doped ones such as the 2% cerium rods work a little better. Use a Dremmel tool and cut the rod to whatever length you like(1-2inches is fine) and hammer it into the main hole until it bottoms out. If it is a loose fit then clamp the brass at its edge in a vise and crimp it a bit to grab the tungsten. Polish the brass so that any scratches in its outer surface run circumstantially and so that when you use the tube to seal it to the glass you will have few if any scratch-based micro leaks. Attach tubing to the outer ends of the rods for the pump on one end and the needle valve on the other and you are ready to go. No excuses.

[Draco]

If i am interpreting this correctly the the main hole does not go all the way through and just slightly smaller in diameter and the gas port would a smaller hole directly next to the main hole with the rod pressed in, but the gas port is at a right angle just before the arc face and the smaller hole then exit's out the back for connection to the gas and vacuum, this i think i can do
The brass got here last week, i could not find it local in the OD i needed so ebay saved the day, i have rod that is about 1 mm bigger then the ID of the quartz, I am going to need to order the tubing to hold the electrodes in place as i cant find that local as well.
I took my caps to 5,000 volts, i was not expecting to get to 5kv but the power supply puts out just enough past it's own rating, i found out that the unit was made to run on 100 volts ac, my nominal here is 118vac but it worked out well.
i am still unsure what i want to do for a trigger source, i figured out how to program the one timer that came with no info so i have reliable timing.

I remember the first time i connected a huge cap to a camera's flash unit, i was told i would get more flashes because of the added capacitance from a local tech, needless to say it exploded

[Draco]

I wanted to ask another question, for the dump load do you and it set up where if there is no voltage on the main relay so it stays connected until the command signla opens the relay allowing to use the cap or is it not that important because of the resistors that bleed down the cap's charge? basically the relay being normally closed when not in use


on a new note i can charge to 4kvdc in less then 1.5 seconds, the current whent off scale of my meter but it did do it

[planters]

With bleeders in place you can forgo the dump resistor.
The gas port does not need the right angle. The tungsten will keep the discharge mostly near its end and away from the gas port.
Carefull...your caps will not live long at 25% above their rated voltage.

[Draco]

That makes it easier to make the electrode.

The 5,000 volts is the rated voltage and i am under by almost 50% in the doubler, I built the doubler for a rating of 8,000 volts. I am getting the parts from an old device that was used to seal plastic with rf energy, from a employer held auction and i got it for 2 bucks, there are more goodies inside, the main power transformer has a 4,000 and 8,000 volt output and a multi tapped primary to select the voltage in steps, i believe this the main plate voltage for the tube in the device, i had always wanted it inside to hold what i am doing now but that never happened, my main caps are too tall and i dont want to start making new holes in the thing yet, i did not do any unresolvable harm to it yet
The breakdown tester is what is slightly over voltage but it has no caps in the path, just the variac, power transformer and some odd ac doubler that has no ratings on it, just ac in and ac out at the same frequency i am guessing it's just an auto transformer and the third terminal is ground though the mounting bolts, it has an overload alarm on it as well, i tend to think the do not go over 1.5kvac was more for testing wire insulation then a warning of internal damage, like other crap i have i can't find any info online.
I cleaned the shed and almost burned it down, i tried starting my quad and it ignited rather then starting, that is a mess in the shed, i am ok and so is the @#$*quad, can't say the same about the floor

[Draco]

i have a question, i can find the tungsten but in two flavors , one set contains 2% thorium and then other set is 2% cerium, witch one should i pick or just use thorium for one and cerium for the other? i have the quartz for 2 lamps.

(Your shed seems to have a lot of clumsy folks wandering through it.) my shed developed a new simptiom, it likes to suddenly catch fire, the float valve was stuck open

[logsquared]

So, I have been following this thread because it interesting. There has been talk about the transformers used to charge the caps. I don't want to de-rail the thread... But I removed this from a lab down the street today and figured its worth posting a pic in this thread. My neighbor's foot is in the pic for size reference.


It has two 120V primaries and a single 2400V secondary. Its rated at 50KVA!!!! So, after the hooking it up backwards and melting a few screwdrivers etc Im not sure what to do with it...

[Draco]

give it to me of course

what does it weigh ?

This also generates a real question on my line transformer, mine is 3kva and has an option for 7200 or 14,400 and was originally in an oil filled can, is it "safe" to use out of the oil? I know it helps with HV insulation and dissipates heat but would it beable to operate for short times with no oil? I would build a plexiglass box to go around it

[planters]

I am slow to respond because PL is no longer notifying me of updates for some reason.

Thorium and cerium both work. Cut the thorium outside because the dust contains a small amount of radioactivity. Don't worry, these electrodes are used frequently today and the radioactive risk is EXTREMELY low, but if there is any risk it is in the dust.

3kva is very low for a line transformer. This is probably some kind of small tap to power equipment from line voltage. The specific voltages are the give away.

I would not operate it out of oil. The oil helps to cool the wingdings, but at this low power rating it is probably included for its insulating properties as well.