Re: This phase shift stuff...

To: tesla-at-pupman-dot-com
Subject: Re: This phase shift stuff...
From: "Antonio Carlos M. de Queiroz" <acmq-at-compuland-dot-com.br> (by way of Terry Fritz <twf-at-verinet-dot-com>)
Date: Fri, 19 Feb 1999 23:12:20 -0700
Approved: twf-at-verinet-dot-com

Tesla List wrote:

>         Here is a question for the students.  If you have a coil 12
inches in
> diameter close wound with #24 wire with a sine signal is applied to the
> base.  How long must the coil be the get a top to bottom phase shift of 45
> degrees in the voltage or current at resonance?  I am not sure all the
> tools exist to answer that question (perhaps they have the high dollar
> software available that could tackle this..), but if they want a
> challenge...
>         If they figure this out, a written report would be very useful to
us!!

This condition will never happen. The phase shift is always 90 degrees
at
resonance, no matter what is the length of the coil (no top load). What 
can happen is, as a vertical coil is a sort of nonuniform transmission
line,
there are losses and irradiation, and the excitation is applied by
magnetic
coupling from the primary, the voltage/current amplitudes along the coil 
may depart somewhat from the ideal 90 degrees sinusoid (voltage) and 
cosinusoid (current).

Antonio Carlos M. de Queiroz