Re: question

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

Original poster: "Antonio Carlos M. de Queiroz by way of Terry Fritz <twftesla-at-qwest-dot-net>" <acmq-at-compuland-dot-com.br>

Tesla list wrote:
> 
> Original poster: "David Thomson by way of Terry Fritz
<twftesla-at-qwest-dot-net>" <dave-at-volantis-dot-org>
> 
> Peter,
> 
> Here's a question for you.  I have a 27" flat spiral secondary.  Connected
> to the outer wire is the positive terminal of a 50KV potential transformer.
> The negative terminal of the 50KV potential transformer is connected to
> ground.  There is nothing connected to the center of the flat spiral
> secondary.  Over the outside of the 27" flat spiral secondary coil I have
> wound a primary of 6 turns of coax cable.  At one of the coax ends I place a
> diode.  Connecting the other end of the coax and the diode to a digital
> voltmeter, I get 150V of DC current when I power up the transformer.
> 
> Why is there an induced voltage in the primary if there is no current
> flowing in the secondary?  And why does the coax cable vibrate?

With 50 kV AC in the secondary you have large electric induction to the
primary, inducing  voltages there. And as the secondary is a coil, 
current flows through it to charge its distributed capacitance. 
This current generates a magnetic field, that couples to the primary 
coil, generating an AC voltage there.
What you see at the primary is a combination of these effects. With a
high-impedance voltmeter, you could obtain a reading by just placing
it close to the setup with the terminals acting as antennas, open to
pick the electric field, and closed to pick the magnetic field. Verify
if you can light a lamp with those 150 V. Or better, connect a capacitor
with a neon lamp in parallel with the output. It will flash.

Antonio Carlos M. de Queiroz