High pressure HGM5 - I'm screwed, aren't I?

[Xytrell]

Would turning the cooling off during your test runs help anything, or just make it worse?

[buffo]

You can't really run these tubes CW without cooling. Even at low tube currents, they generate a lot of heat. The thermal interlock will shut it down after 20-30 seconds of operation with no cooling.

I suppose getting it really hot might help the process a tiny bit, but it could also ruin the tube, so I'm leery of bypassing the over-temp interlock.

Besides, it's my understanding that the gas burying process is very slow until you reach extreme temperatures (thousands, not hundreds of degrees F) anyway. So heating it up to a few hundred degrees probably won't do a lot of good.

Adam

[buffo]

Ok - I hooked the tube back up to the HGM5 PSU last night and fired it up. I was able to run it for a little over 14 minutes at 5 amps of tube current before it winked out (at 314 volts across the tube). So it appears that the HeNe PSU is helping. I'm going to let it cook for another 4 days or so and try it again. (Crosses fingers)

Adam

[Phredy1]

Ok - I hooked the tube back up to the HGM5 PSU last night and fired it up. I was able to run it for a little over 14 minutes at 5 amps of tube current before it winked out (at 314 volts across the tube). So it appears that the HeNe PSU is helping. I'm going to let it cook for another 4 days or so and try it again. (Crosses fingers)

Adam

The power company is going to love you

[buffo]

Not really. The HeNe PSU draws next to nothing. It's rated for 2700 volts at 6.5 ma current, which yields a power of roughly 16 watts. Even if the PSU is only 50% efficient, that's still means it's drawing less power from the wall than a standard light bulb would. (I probably should have made it clear that when I said I'm going to let it cook, I meant on the HeNe PSU, since that's the only way I can get it to sustain a plasma for any appreciable length of time.)

Now, when I get to the point where I can run the tube on the HGM5 supply at 5 amps of tube current for several days, *then* I'll be using some serious juice. (On the order of 1.5 to 2 KW.) So that will be like leaving a burner on the stove running continuously. But I'm not to that point yet.

Adam

[mixedgas]

Thats gonna be a long slow process. May be time to try getting the current up. Might want to look at the plasma spectrum with the mark one eyeball and a grating and see if there are any bands there, while excited with the hene.. spectral Lines = argon, bands = trash, unless you see a H2 balmer series with the argon...

Steve

[Doc]

What about a rectified microwave TX (with a series resistor obviously) 2.2kv @ 500mA to play with?

EDIT: You can insert the resistor in the primary side, either that or balast it with a second MOT in series, with it's secondary open circuit.

**Danger Will Robinson, use caution around these angry little transformers!**

[buffo]

Steve;

Should I be looking down the bore with the grating, or are you talking about looking at the plasma glow from the side of the brewster stems? (I'm assuming we're talking about doing this while it's running on the HeNe PSU, right? No way I'm looking down the bore with it running on the Argon PSU! Unless I take the optics out first, that is...)

The glow from the side of the stems is *very* hard to see when running on the HENE psu, because it's so dim. Looking down the bore is not a problem when it's running on the HENE psu, but I'm thinking that the optics will have to be removed to get an accurate reading, right? (If I look down the bore with the optics installed while it's running of the HENE psu, I see a magenta color...)

For what it's worth, when it's running on the Argon PSU, the plasma color seen from the side of the brewster stems looks normal.

Doc;

If I had a cheap way to rectify the HVAC, I have a 6500 volt neon sign transformer that puts out around 40 ma that would be rather useful. But Steve said that DC (and reverse-biased DC at that) would be more effective than the AC I'd get from the neon sign transformer. And I don't have a full wave bridge rectifier that can handle 6.5 KV.

Adam

[Laser Zone]

Adam try calling Dean at nitelite products , tell him that Norman from florida referred you to him. Tell him your problem and your low on cash and see what he says. He's a good guy and hopefully he can help you out like he's helped me out in the past. (805) 529-2176 ask for Dean http://www.niteliteproducts.com/

[Doc]

Doc;

If I had a cheap way to rectify the HVAC, I have a 6500 volt neon sign transformer that puts out around 40 ma that would be rather useful. But Steve said that DC (and reverse-biased DC at that) would be more effective than the AC I'd get from the neon sign transformer. And I don't have a full wave bridge rectifier that can handle 6.5 KV.

Adam

An old microwave contains everything you need, magnetrons run on half wave DC