Re: [TCML] power losses through GTO wire

["drieben" <drieben@xxxxxxx>]

Jeff,

Dave Speck is right on the money with his explanation.
The transmission line conductors that lead from your HV
source to your main tank circuit (loop that forms the tank
capacitor, spark gap, and primary coil), can be relatively
small and amperage can genreally be measured in frac-
tions of or in low single digit intergers for even very large
coil systems) and, as Dave stated, even #18 wire would
be sufficient for this purpose. Once INSIDE the tank cir-
cuit loop, the peak current levels are much greater than
the continuous current levels that transverse the transmis-
sion lines that lead from the HV source to the tank circuit
loop (usually measured in the 100s of amps for even mo-
dest sized systems). Therefore, the conductors used inside
the tank circuit loop should be of a much heavier guage and
the runs should be kept as short and direct as possible.
Some coilers use welding cable or heavy braided grounding
strap for this purpose. Remember, a Tesla coil is a POWER
amplifier but it does NOT cause a net gain in its output
ENERGY vs. its input. I'll leave further explanation of this
principle to the better learned elite of this forum ;^)

David Rieben


----- Original Message ----- 
From: "jeff mill" <jeffmill2@xxxxxxxxxxx>
To: "Tesla Coil Mailing List" <tesla@xxxxxxxxxx>
Sent: Saturday, February 18, 2012 7:02 PM
Subject: Re: [TCML] power losses through GTO wire


> Thank you all for the reassurance on the size of my secondary. This is 
> actually my first small/medium sized tesla and even with all the resources 
> out there, man and there is a lot, you still question yourself. I work 
> with large UPS back up systems but have never experianced  or worked with 
> the high voltages / theory of the tesla but always wanted to learn.
> I guess what I reaaly wanted to know is will I see a large increase in 
> performance when I actually shorten the 12ft x 2 wires to the primary 
> down to , say 1ft. I work with Higher currents and lower V in my trade, so 
> be easy on me, here is how
> I picture it. If I'm pulsing say 200amps to my primary  the dc resistance 
> is very low in the primary with 8 turns of 1/4 inch copper, just to grab a 
> number , say .1 ohms. Then say my gto , 24ft is .1 ohms then half of my 
> power going to the primary is lost across the gto wire length ? I know 
> this isn't correct in thinking, so help me see the light.

From: "David Speck" <Dave@xxxxxxxxxxxxxxxx>
To: "Tesla Coil Mailing List" <tesla@xxxxxxxxxx>
Sent: Saturday, February 18, 2012 8:35 PM
Subject: Re: [TCML] power losses through GTO wire


> Jeff,
>
> As elsewhere mentioned, losses in the spark gap are a significant factor 
> in the operation of the coil.
>
> That said, I endeavor to use relatively heavy gauge conductors in the 
> primary circuit -- i.e. the loop between the ends of the primary coil, the 
> primary cap, and the spark gap. When the primary is oscillating, you have 
> 100 - 200 amps sloshing back and forth at RF frequencies, so I would avoid 
> GTO cable anywhere in that loop. Try to keep the cables as short as 
> practical and use good connectors throughout.
>
> The leads from the HV transformer to the cap can be smaller -- even a 15 
> kVA pole pig can only supply about one amp max at 14.4 kV, so 18 Ga GTO 
> from the transformer to the primary should be adequate.
>
> Remember that current thinking suggests placing the gap across the HV 
> transformer. Although it seems counterintuitive, this arrangement helps 
> protect the transformer secondary windings from excessive spikes during 
> primary circuit ringdown.
>
> Dave


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