Re: [TCML] Help choosing tank caps for dual MOT

[jhowson4@xxxxxxxxxxx]

Just to throw my 2 cents in here, 

A quick Google search yielded the discovery that option 1 uses paper as a dielectric, not ideal for tesla use. 

option 2 i could find no information on, but be wary because people on ebay love to put Tesla in the description for things, regardless of its actual purpose or not. 

option 3 well yea its gonna work, i cant really say much about which size would be better though. 


but might i present option 4 
A home made poly cap could be made for your voltages relatively easily and cheaply. I have been doing alot of digging into the poly caps information as I am having the same problem sourcing a capacitor. 
I am assuming that you are seriesing the 2 mots and doubling them? 
Running the numbers threw my little excel calculator I made. 
and using the advice that your capacitor should be moderately over rated so it does not cook itself. 

you could make a .1uf 9600V capacitor using 135ft of the 6mil poly which could easily cost you 50-60 for the plastic. that of course is excluding the costs of aluminium for etc etc. over all the price would be almost 60-80 depending on how fancy you want it. 
The resulting cap would be rated for ~40kv plenty of head room and be pretty bullet proof when running off your mot supply. in my opinion. You could even put it under oil if you were feeling ambitious but at the lower voltages it should not be necessary. 

I personally have used the home brew caps for the past 6 years with out failture, 2 are open air, 1 is under oil. the air units run off a obit supply (10kv) and I have had about 10 obits in parallel at one time or another. 
I personally love the home brew caps, but other people seem to have trouble with them. 



Thanks, 
John "Jay" Howson IV 


"Why thank you, I will be happy to take those electrons off you hands." 


----- Original Message -----
From: "James Hutton" <b-u-r-t-o-n-boy@xxxxxxxxxxx> 
To: "tesla help" <tesla@xxxxxxxxxx> 
Sent: Thursday, September 1, 2011 12:14:30 AM 
Subject: [TCML] Help choosing tank caps for dual MOT 


Hello coilers!I'm building a dual mot tesla coil, and I need some help building the tank cap.For me, money is definitely a limiting factor. Otherwise I would just spend 70 bucks on 942c16p15 cornel caps.I'm looking for around 70-100nf at 10kv (I think that should be good...) 
I have a couple options that i've found... I just have lots of bad luck with capacitors (I bought the 940c series for my one coil and they pop like popcorn!)So I want to make sure I get really reliable caps. (especially since this coil is going to be used for long run-times in a show)So I'm bringing the options to the pro's at pupman :) 
option 1: http://www.ebay.com/itm/0-5uF-5-2500V-PIO-PULSE-Capacitor-K41-1a-RARE-1945-/140485977230?pt=Vintage_Electronics_R2&hash=item20b59de48e#ht_863wt_1037 0.5uf 2500v 4 caps in series 10,000v 125nf ~ $60 
option 2: http://www.ebay.com/itm/Capacitor-Oil-Filled-GE-1-Uf-5-000-Vdc-Tesla-HV-/350479314939?pt=LH_DefaultDomain_0&hash=item519a31effb#ht_1225wt_1037 0.1uf 5000v 2 caps in series 50nf 10,000v ~$50 
option 3: of course, the 942c16p15 cap (but it is pretty expensive) 0.15 1600v 6series 2strings = 9600v 50nf or 6series 3strings = 9600v 75nf(Which one would be better?) 
I will reluctantly buy the 942c like everyone says if it truly is worth it. If those other two will give me just as good results, then I'll for sure get them, but if 942c is a lot better then I'll get them. 
thanks for all the help guys. I really appreciate all the advice you guys give on this site. You guys have literally made my dreams of making my own lightning a reality.never could have done it without the advice from this place :) 
here's a video of my first tesla coil if you guys wanna see it: http://www.youtube.com/watch?v=dkIgMYqtU4sthanks again! 
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