# Re: HOW MUCH POWER NEEDED FOR A TC?

```Tell him about top capacitance, and the fact that we're talking about 3d
volume
effects, not area/linear effects. (More space to be ionized.)

Also tell him to go learn something about tc building before he tries to
mentor
a tc project.

Tesla List wrote:

> Original Poster: "Marco Denicolai" <Marco.Denicolai-at-tellabs.fi>
>
> HELP!
>
> As you maybe know I am designing a new TC to be built at the High Voltage
> Institute, Helsinki University of Technology.
>
> The current problem is that the professor mentoring my project DOESN'T
> BELIEVE my new TC will require 20 kW of power!
>
> He wants to have some clear justifications for it, as he thinks a huge part
> of the power is not wasted (!) or (another explanation) the most of it is
> just reactive (not real) power.
>
> The TC I am designing has got the following characteristics:
>
> - secondary 15.7" diameter, 59" tall, 88 mH, f=102 kHz (57 kHz loaded)
> - primary 78 uH flat pancake
> - top load toroid inner dia. 9.8", outer dia. 59", about 61 pF
> - primary capacitor 0.1 uF
> - break rate adjustable up to 800 BPS.
>
> Looking at the other coiler's TC I decided 16 kW would be a proper power,
> 20 kW just to leave some margin.
>
> I NEED YOUR HELP TO JUSTIFY THIS MY DECISION (or to change it, if needed):
>
> - how to show relationship between coil size and needed power (to get some
> decent performance)?
> - how to show were the power is dissipated and that it's not simply
> reactive?
>
> My professor is going to measure the power absorbed by my present TC
> (secondary 4.33", 19.7" tall) and to extrapolate it: I think he will
> measure about 2 kW and multiplying by four (new TC is 3 times taller) will
> easily end up with 8 kW only (!).
>
> If I am not able to explain to him the above issues he will not let me
> build it with a 20 kW tank supply... :(
>
> Waiting for help...
>
> P.S. Here the question is not "How much power do I need at 800 BPS with a
> 0.1 uF capacitor". The real question is "In general, how much power do I
> need to excite a TC of this size?".
>  My tentative design featured a 10 kV transformer, rectified to a 14 kV DC,
> that using resonant charging ramps up to 30 kV to charge the primary
> capacitor. At 800 BPS the energy is  E = 800 * 0.5 * 0.1E-6 * 30000 * 30000
> = 36 kW.
> Limiting power to 20 kW I could charge the capacitor (-at-800 BPS) to about 22
> kV, more than sufficient.

--
--Mr. Postman (Doug Brunner)