Re: coupling losses ? (fwd)

["Tesla list" <tesla@xxxxxxxxxx>]

---------- Forwarded message ----------
Date: Sat, 22 Sep 2007 11:19:39 +0100
From: Chris Swinson <list@xxxxxxxxxxxxxxxxxxxxxxxxx>
To: Tesla list <tesla@xxxxxxxxxx>
Subject: Re: coupling losses ? (fwd)


HI Bert,

> A SISG substitutes a chain of solid state switches (IGBT's) for the
> spark gap. This approach significantly reduces switching losses, but the
> rest of the system losses still remain. Since the overall losses are
> lower in an SISG coil, a greater portion of primary "bang" energy can
> make it to the secondary, and with proper adjustment, quenching can also
> be tightly controlled. As a result, an SISG coil is measurably more
> efficient (when measured as output spark length versus input power) than
> an otherwise identical coil that uses a spark gap switch.

the SISG seem to output a spark length at 100watt input compaired to my 500W 
tesla coil, it was looking to me like the main losses were in the spark gap. 
a couple 100 volts isn't going to matter that much if thats the drop over a 
spark gap.



> Once the gap fires, it will NOT stop conducting until the primary
> circuit energy has fallen to zero (sometimes called the first current
> "notch"). Even though there are brief zero current crossings at the RF
> operating frequency while energy is being transfered to the secondary,
> the gap always reignites. When the gap finally stops conducting, the
> remaining "stranded" primary voltage will be 200 volts or less...

Right, so in effect once the gap fires at 10KV, you can pretty much say its 
a wire link until current drops to zero and the "wire link" cannot be 
anylonger maintained.

> The values you appear to be using in your secondary simulation (10
> turns, 100 (uH) seem to be quite far removed from values used by either
> Tesla or today's researchers. Did you take into account skin or
> proximity effects at the assumed (relatively high?) operating frequency
> in your simulations? Larger diameter wires show larger changes in the
> RAC/RDC ratio than small wires.


skin effect , or resistance, was a lumped sum of resistance, All I did was 
increase each factor one at a time to see what would happen. I suppose I 
should relate it to AC resistance which might not be so linear ?

cheers,

chris