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Re: V11.1 for JAVATC (fwd)
---------- Forwarded message ----------
Date: Fri, 31 Aug 2007 19:55:40 -0700
From: Barton B. Anderson <bartb@xxxxxxxxxxxxxxxx>
To: Tesla list <tesla@xxxxxxxxxx>
Subject: Re: V11.1 for JAVATC (fwd)
Hi Tony,
I built a plate cap early on submerged in oil. All I can say is messy,
heavy, and I wish MMC's were around back then. After that miserable
experience, I decided to build a rolled pvc cap. About the time I had it
all worked out I happened across some pulse caps. Regarding economy, a
bottle cap is easy and cheap also. But, my comments about costs were
specific to MMC's if one is going that route.
Something to mention about caps from manufacturers is that the caps are
built by clean room machines to a fine tolerance better than one could
ever do on their own and with minimal contamination (which in itself is
a problem for caps). So there is another good reason to go with caps
from a manufacturer.
There's nothing wrong with someone building their own if that's what
they want to do. It does make my eye twitch when a I see a coiler ask "I
built my own cap and it died. Why?".
Caps have always been the expensive part to coils which is why so many
built rolled caps, plate caps, bottle caps, etc.. up until MMC's came
along. MMC's really helped to get the cost to a reasonable level, but if
the cap size desired is huge, you might be better off with one or two
professional pulse caps. There are are higher value Cornell Dubilier
caps in the 1600VDC range (vs the usual 2000VDC range), but if you ever
do an analysis on availability and cost per cap for any given
capacitance, you'll find the 0.15uF 2000VDC version will actually be
less expensive. It sucks but it's true. So, when you need to build a
largish cap, a professional pulse cap might be the best alternative.
On the other hand, double your break rate and you can reduce the LTR
value by half. This helps with the number of caps required and cost.
There's not a lot of difference in spark output between 120 and 240 bps.
Just a thought. Besides, for a SRSG at 240 bps with a .05uF cap, well,
that is just a nice configuration. And further to that, as D.C. had
suggested around 0.04uF, that is doable as well. It's still LTR, just a
little less. So 240 bps at .02uF (see how the cost comes down?).
Take care,
Bart
Tesla list wrote:
>---------- Forwarded message ----------
>Date: Thu, 30 Aug 2007 23:04:47 -0700
>From: Anthony R. Mollner <penny831@xxxxxxxxxxxxx>
>To: Tesla list <tesla@xxxxxxxxxx>
>Subject: RE: V11.1 for JAVATC (fwd)
>
>Hi Bart,
> From an economic point of view it could cost more money for the capacitors
>than for every other part of the tesla coil combined. I would imagine that
>the ultimate capacitor would be a tank of oil with plates in it, that would
>last for all of time! Of course it would be huge but hey, why not?
>
>Tony
>
>-----Original Message-----
>From: Tesla list [mailto:tesla@xxxxxxxxxx]
>Sent: Thursday, August 30, 2007 7:37 PM
>To: tesla@xxxxxxxxxx
>Subject: Re: V11.1 for JAVATC (fwd)
>
>
>
>---------- Forwarded message ----------
>Date: Thu, 30 Aug 2007 18:03:45 -0700
>From: Barton B. Anderson <bartb@xxxxxxxxxxxxxxxx>
>To: Tesla list <tesla@xxxxxxxxxx>
>Subject: Re: V11.1 for JAVATC (fwd)
>
>Hi Tony,
>
>Consensus on voltage ratings varies in the two extremes. I am on the
>side of making the cap robust for longevity. But even that is relative
>to how long and hard you run the coil. There is degradation of the caps
>over use and time (this is a proven fact). Yes, you can get away with
>minimum deratings, but for how long? For some, it may be the life of
>their coiling experience and for others only a short while. You can
>however maximize the derating for voltage standoff and know that it will
>last a good long while even if you run the coil every day. That's what I
>prefer. At the time I built my own, I decided to error on the side of
>longevity.
>
>The cost of a cap bank must be considered. When the cost is just too
>much for maximum derating, there are middle grounds between the extremes
>you may be forced to take. Cost increases with coil power which
>partially determines cap size, so when building a coil, it's wise to
>design and evaluate the cost before you build.
>
>Take care,
>Bart
>
>Tesla list wrote:
>
>
>
>>---------- Forwarded message ----------
>>Date: Wed, 29 Aug 2007 17:39:08 -0700
>>From: Anthony R. Mollner <penny831@xxxxxxxxxxxxx>
>>To: Tesla list <tesla@xxxxxxxxxx>
>>Subject: RE: V11.1 for JAVATC (fwd)
>>
>>Hi David,
>> Well, that seems to be what I've discovered as well. Now it's time to put
>>a s@#t load of CDE caps together. What's the consensus on the voltage level
>>for each string? I have heard of some guys running those 942C caps right at
>>the transformer AC output, in my case 15kv but, that really doesn't sound
>>wise to me. On the other hand, running strings of 21+ will cost an arm and
>>
>>
>a
>
>
>>leg and various other body parts that I'd like to hang on to! So, what does
>>everyone think would be nice and safe?
>>
>>Tony
>>
>>-----Original Message-----
>>From: Tesla list [mailto:tesla@xxxxxxxxxx]
>>Sent: Wednesday, August 29, 2007 5:47 AM
>>To: tesla@xxxxxxxxxx
>>Subject: RE: V11.1 for JAVATC (fwd)
>>
>>
>>
>>---------- Forwarded message ----------
>>Date: Wed, 29 Aug 2007 12:44:50 +0000
>>From: David Rieben <drieben@xxxxxxxxxxx>
>>To: Tesla list <tesla@xxxxxxxxxx>
>>Cc: drieben@xxxxxxxxxxx
>>Subject: RE: V11.1 for JAVATC (fwd)
>>
>>Hi Tony,
>>
>>Well, let's see. 60 Hz mains resonance with a 15/120 transformer(s) is
>>about .02 uFd and the general consensus on capacitor size with SRSGs
>>in NST systems is about 2.8X resonant capacitance value, that would
>>come out to .056 uFd. So .055 uFd sounds just about "right on the mo-
>>ney" to me :^)
>>
>>
>>David Rieben
>>
>>-------------- Original message --------------
>>From: "Tesla list" <tesla@xxxxxxxxxx>
>>
>>
>>
>>
>>
>>>---------- Forwarded message ----------
>>>Date: Tue, 28 Aug 2007 07:23:48 -0700
>>>From: Anthony R. Mollner
>>>To: Tesla list
>>>Subject: RE: V11.1 for JAVATC (fwd)
>>>
>>>I like this program, it's a real time saver. I was surprised at the
>>>capacitor value it figured for my set up. I'm running a 15/120 input with
>>>
>>>
>>>
>>>
>>a
>>
>>
>>
>>
>>>SRSG and the value that JAVATC gave me of .055 for LTR. This was a lot
>>>higher than I would have imagined, does that sound right?
>>>
>>>Tony
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
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