Re: [TCML] primary voltage

[Brandon Hendershot <mrbrandman@xxxxxxx>]

Hi Matt,

Reading your post was kind of disturbing! You said all that happens  
somewhere inbetween 30 and 100 kV?Is there a tighter more precise  
range you know of? Because my coils primary circuit voltage will be  
hovering around 36kV. Should I be too worried about insulating every  
little point and wire? If it matters at all, I'm installing a Terry  
filter too. Those chunky resistors won't affect the issue much I assume?

Thanks,
Brandon

On Jan 7, 2010, at 1:13 PM, mddeming@xxxxxxx wrote:

> Hi Kevin,
>
> While some people have experimented with primary voltages in to  
> 30-100 kV range, there are several distinct problems with primary  
> voltages much above 15 kV (rms).
> 1) Costs: The number of caps in an MMC goes up as the square of the  
> voltage (twice V = 4 x number of caps). Above ~15 kV you are also  
> talking custom-made transformers: Cost and weight increase  
> exponentially with voltage.
> 2) Corona problems: above about 20 kV, every point, twist, kink,  
> bend, or screw head in the primary wiring becomes a source of corona  
> leakage which is power lost.(but the blue glow looks "cool".to  
> some). These losses increase rapidly with voltage level.
> 3) Insulation  breakdown: most HV wire tops out at 30-40 kV then you  
> start needing to get into X-ray equipment cables, or custom, or home- 
> made cables made from coax. Even wire run through plastic tubing  
> starts to have problems at higher voltages.
> 4) Unintended Coupling: as voltages go up, there is an ever  
> increasing tendency of currents in the wire to couple capacitively  
> or inductively to nearby objects and power, telephone,etc. lines,  
> charging them to "unpleasant" levels and wasting spark energy doing  
> it.
>
> In short, it is much more cost, weight, and safety efficient to keep  
> primary voltages at the level of mass-produced transformers and  
> minimize the number of caps needed to still keep a good working  
> margin.
>
> Hope this helps,
>
> Matt D.
>
>
>
>
>
>
>
>
>
>
>
> -----Original Message-----
> From: makinglightning@xxxxxxxxxxx
> To: Tesla Coil Mailing List <tesla@xxxxxxxxxx>
> Sent: Thu, Jan 7, 2010 12:27 pm
> Subject: [TCML] primary voltage
>
>
>
> What is the practical upper limit on the primary tank circuit?
>
> What is the highest primary tank voltage that people have used?
>
> Kevin
>
> _______________________________________________
> esla mailing list
> esla@xxxxxxxxxx
> ttp://www.pupman.com/mailman/listinfo/tesla
>
> _______________________________________________
> Tesla mailing list
> Tesla@xxxxxxxxxx
> http://www.pupman.com/mailman/listinfo/tesla
_______________________________________________
Tesla mailing list
Tesla@xxxxxxxxxx
http://www.pupman.com/mailman/listinfo/tesla