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Registered Member #54655
Joined: Thu Mar 19 2015, 05:56PM
Location: BC, Canada
Posts: 82
I have a magnifier running on 2 mots at about 400-500 bps async and the cap bank is only 2 strings of 6 each and it works fine producing 5 foot bright streamers. These caps are tough and will have no problem at all with only 2 strings. Also I have found that 1.3 times the resonant value works the best for nst's, 34nf would be 1.6 times resonant and most people recommend not going higher then 1.5 times. So even with only 2 strings the lifetime of your caps will be way more then you will ever need. You should only start to worry if the caps get hot.
Registered Member #54484
Joined: Sun Feb 15 2015, 06:18PM
Location:
Posts: 46
Graham Armitage wrote ...
For what it's worth, I have had much better results from an air gap than RSG, especially when using NSTs. One of the most successful (and easiest) gaps I built was with two thin walled 1" pipes aligned axially and separated by the desired gap. One pipe was close and attached to a handle to adjust it closer or further from the other pipe edge. The second pipe was attached to small vacuum cleaner. This pulled air from outside the pipes and back into the "exhaust" pipe. I enclosed the whole thing in a muffler box to reduce light and noise but allow air flow. Because of the high flow rate of the air the spark was quenched very quickly which is what you want. Hope this helps.
Results can be seen here -
Thank you. For some reason I didn't even think of using a vacuum motor. I have an old Kirby with a very strong motor in it. I plan to build one similar to this one.
Registered Member #54484
Joined: Sun Feb 15 2015, 06:18PM
Location:
Posts: 46
Benjamin wrote ...
I have a magnifier running on 2 mots at about 400-500 bps async and the cap bank is only 2 strings of 6 each and it works fine producing 5 foot bright streamers. These caps are tough and will have no problem at all with only 2 strings. Also I have found that 1.3 times the resonant value works the best for nst's, 34nf would be 1.6 times resonant and most people recommend not going higher then 1.5 times. So even with only 2 strings the lifetime of your caps will be way more then you will ever need. You should only start to worry if the caps get hot.
Awesome thank you! I'll just keep it the way it is and kill 2 strings. That way if some caps blow all I have to do is switch to the other set. Cool
Registered Member #6038
Joined: Mon Aug 06 2012, 11:31AM
Location: Salado, TX
Posts: 248
That looks cool. How do you tune the gap distance? It looks like air is being sucked through both tubes. Have you tried blocking one so that the force of air moving through the gap is greater? Could change how quickly the spark is quenched.
Registered Member #54484
Joined: Sun Feb 15 2015, 06:18PM
Location:
Posts: 46
I cut slots in the pipe for adjustment. You can see in the pic below. I'll probably end up wrapping tape around the opening until can figure out a different method. I just wanted to be sure the electrodes would remain secure once the gap was set. As far as plugging one of the holes, I'll try that after I test it with the coil. I was just thinking there would be a more even flow if both were open.
Registered Member #54484
Joined: Sun Feb 15 2015, 06:18PM
Location:
Posts: 46
Just tested it. took me a couple minutes to figure it out but it was arcing "inside" the secondary, there's trace marks everywhere. My top load connection is outside and the ground is inside. Apparently neither should be inside so I'm going to change the ground connection to outside. The only reason I had it inside was for aesthetics, whatever, at this point I don't care. I'm also going to try and figure a way to seal the inside of the secondary at the top and bottom.
Registered Member #54484
Joined: Sun Feb 15 2015, 06:18PM
Location:
Posts: 46
Here it is. Still got to fine tune but its already too powerful for my little room. Plus there's too much stuff all around it. Check out the video link below and thank you very much everyone for your help! I never even went above 90 volts on the variac.
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Rotary vs Air Blast gap
