Re: Why do primaries get hot?

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "S & J Young by way of Terry Fritz <twftesla-at-qwest-dot-net>" <youngs-at-konnections-dot-net>

Hi Greg,

Remember that at RF frequencies the so-called skin effect comes into the
picture.  That is, the current through the tubing is mainly in a thin layer
on the outside of the tubing, not evenly distributed through the volume of
the tubing.  This can result in more ohmic heating than if it was DC or low
freq AC.

The other possibility is the mechanism to tap the primary does not make a
solid connection, and generates heat.  The copper, being a good heat
conductor, could distribute this heat through at least some of the turns.

--Steve
----- Original Message -----
From: "Tesla list" <tesla-at-pupman-dot-com>
To: <tesla-at-pupman-dot-com>
Sent: Thursday, February 28, 2002 7:51 PM
Subject: Why do primaries get hot?


> Original poster: "Gregory Hunter by way of Terry Fritz
<twftesla-at-qwest-dot-net>" <ghunter31014-at-yahoo-dot-com>
>
> Dear List,
>
> Why do primary coils get warm? I'm aware of the insane
> current pulses, but they are of only a few uSec
> duration. The Cu tube coil should integrate the
> various currents with respect to time, like a heater
> element, thereby arriving at the average current. The
> average power supply current of even a monster Tesla
> coil is under an amp. 1/4" or 3/8" Cu tube should be
> able to carry a few 100ma all day without warming up.
> Is it RF heating?
>
> Cheers,
>
> Greg
> http://hot-streamer-dot-com/greg
>
>
>