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Re: [TCML] Capacitor for the 10 in. coil
Thanks for the compliment on the spark gap, I put months of work into it. =)
In my video of actual sparks I am running a 120:1 PT at close to 3Kva 16.8Kv output, with 20 nf capacitance.
But for the video of just the spark gap it self I am only running the gap at maybe 25% on the variac, it a little over where it just started to spark.
Here are the videos for those interested
The gap was developed for my new coil, which is awaiting capacitors which is why I have been collecting info on various arrangements to get a feel for what works and if i can apply that to my system. Its a DC coil so the max voltage the caps see is actually close to 24Kv, as opposed to the ~17Kv your cap bank sees. Mine too runs close to 450 Bps but has the capability to reach 600 which was my original goal, but after looking at rms currents I decided it was best to back it off a bunch.
I will be adding a magnetic pickup to the gap or something of the sort so I can determine exactly how fast it is going and calibrate a scale on my variac accordingly.
Did running at your power level have you noticed any degradation from the copper electrodes? Your cap "Bang" must be intense as you have just about tippled my capacitor size. I noticed a little bit on my thoriated rotary electrodes after maybe 30 min of total run time.
Have a great one ,
John "Jay" Howson IV
"Why thank you, I will be happy to take those electrons off your hands."
----- Original Message -----
From: "Jason Kerlin" <kerlinjason@xxxxxxxxx>
Sent: Monday, July 2, 2012 7:32:06 PM
Subject: [TCML] Capacitor for the 10 in. coil
The capacitor for the big coil is a Maxwell MMC. There are 5 strings of 2 for a cap. of 76.4 nf. They are the 37767 caps at 35 kv and 30nf. They were all purchased used from e-bay. Very easy to integrate into the coil. After an 8 minute run I could barely feel any warmth coming off of the bank. The cap is connected with .125 flat ribbon copper that is 1" wide. Cap is in series with primary.
At John IV,
:That last message should be for Jason. My apologies for mis-typing your name.
Thats cool. You can call me a fellow coiler. I really like the effect your sparkgap gives in those tests on youtube. How much power have you ran through that gap?? Anyway lets see if I can give some more info on my coil : It is powered by a 12470/240 sec/pri rated 10kva. I am not sure what actual current is, but will be putting amp and volt meters in the control panel. It is ballasted by two cores out of a Lincoln 250 that are rewound with a gap cut and shimmed with PC. The transformer has a tap setting on the side and it is set at 105%. The sparkgap motor is 1 1/2 hp 3600rpm. There are 8 electrodes that are .5 in. brass threaded rod. The stationary electrodes are 1/2 copper studs out of a giant starter. Ballast L is 8.89mh on the primary side of the pig.
I have ran the coil for about 3 hours all together with runtimes of about 4-5 min average. 2 days ago I let it go for about 9 minutes as I got everything in tune. No warming of the caps this time as previous runs were at 720bps. I just finished the new sparkgap plate last wednesday to reduce heating in the caps by lowering to 480bps. They (the caps) are only rated 500 pps, so best not to overdrive them to much.
It seems the coil is constantly changing as I make improvements (well, sometimes they are improvents, other times....). I would be glad to answer any questions from all.
working on new topload
Jason in S.D.
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