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Re: [TCML] primary voltage



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

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