Re: [TCML] RSG Cooling - was - a new coil being born + PICTURES

[Bert Hickman <bert.hickman@xxxxxxxxxx>]

Hi Adam,

This is related to the recent "Gaps" thread (BTW, there was a 
transcription error in the table I showed for 2nd notch quenching). You 
can get a ballpark estimate if you know how well your coils is 
quenching. First notch quenching (a single Primary --> Secondary energy 
transfer followed by quenching) is an ideal quench). Spark gap coils 
usually don't quench on the first primary current notch. Most well 
designed SG coils begin quenching on the 2nd or 3rd notch (or worse). 
Also, in well designed coils, about 15% of the system energy is lost in 
the gap during a complete P -->S energy transfer or S --> P transfer (if 
the gap fails to quench). The "worst case" gap loss, as a percentage of 
bang size, can thus be estimated depending on which notch you're 
quenching at:

Primary   Percent of bang
Current   energy being lost
 Notch:   within the gap (X)
=======   ================
  1		15%	   	
  2		39%
  3		56%
  4		68%
  5		77%

You can take the above quenching factor (X) and multiply it by bang size 
and BPS to arrive at the "worst case" power dissipated by the spark gap:

Wgap = X * Bang Size * BPS  (watts)

As mentioned, the above will be worst case. Actual gap dissipation will 
be a somewhat less when your coil is breaking out. As heavy streamer 
loading removes significant system energy, quenching becomes easier, and 
solid ground strikes result in an immediate quench. It's not unusual to 
see a system that initially quenches at the 3rd or 4th notch improve to 
2nd notch and even intermittent 1st notch quenching when the coil is 
really cooking at full power. The converse is also true - poor tuning or 
no breakout will cook your gap electrodes.

Bert
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Yurtle Turtle wrote:
> This thread got me thinking... Is there any consensus over
> "approximately" how much power is lost (heat I need to remove)
> through a rsg? I have a 10" pig/coil I usually run at around 10 kVA
> with a "four gap" rotary. If I were to try and design a cooling
> system, what would a good rating be for watts to dissipate? I
> probably run around 400 - 480 bps with a 100 nF cap. I wanted to
> check the Joules per bang, but hot-streamer is down and that's where
> I have my specs.
>
> Adam
>
> --- On Tue, 7/29/08, Jeremy Scott <supertux1@xxxxxxxxx> wrote:
>
> > From: Jeremy Scott <supertux1@xxxxxxxxx> Subject: Re: [TCML] a new
> > coil being born + PICTURES To: "Tesla Coil Mailing List"
> > <tesla@xxxxxxxxxx> Date: Tuesday, July 29, 2008, 11:05 AM
>
>
>
> > > It'll be interesting to see how hot it gets.
> > Yeah I thought that might be an issue too but I'm not too
> > concerned. The purpose of the ballast is to ramp up to full power 
> > slowly so most of the time the core won't even be in. I built
> > everything for 50A but realistically I'll probably only run it at
> > 30A. (#10 wire in the ballast.)
> >
> > > > Here's some of the  50A 220V cables I'm
> > going
> > > to use. TIP: Recreational
> > > > vehicle (RV)  stores are a great supply for 50A
> > > extention cables.
> > >
> > >
> > > That's a great tip, thanks!
> > >
> > > > Maxwell Caps. I've had these for awhile. 100KV
> > @
> > > 10nF.
> > >
> > > > I can easily short out the last capacitor for 70KV
> > @
> > > 15nF:
> > >
> > > http://mywebspace.wisc.edu/jeremyscott/web/MaxCaps.JPG
> > >
> > >
> > > I hope those outside terminals don't come too
> > close to
> > > all that pretty wood!
> > They actually go through the wood on the ends of the box and there
> > are two screws that I crank down to sandwich the bank together.
> > When I want to take a capacitor out, I loosen the press and stick
> > some wire in there to short out one of the capacitors then tighten
> > it again. Is that bad? I've used this capacitor bank before without
> > problems, and I coat the exposed terminals with polyurethane for an
> > extra little bit of insulation. (Home Depot has this liquid rubber
> > stuff I want to try, but it's ugly orange.)
> >
> >
> >
> >
> >
> > _______________________________________________ Tesla mailing list 
> > Tesla@xxxxxxxxxxxxxx http://www.pupman.com/mailman/listinfo/tesla
>
>
>
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