[Prev][Next][Index][Thread]

Re: Pri-Sec Phasing





---------- Forwarded message ----------
Date: Wed, 8 Oct 1997 17:10:11 +1200
From: Malcolm Watts <MALCOLM-at-directorate.wnp.ac.nz>
To: tesla-at-pupman-dot-com
Subject: Re: Pri-Sec Phasing 

Hi Greg,
        Yes, measurement was taken at resonance.

> From: Greg Leyh <lod-at-pacbell-dot-net>
> To: Tesla List <tesla-at-pupman-dot-com>
> Subject: Re: Pri-Sec Phasing 
> 
> Malcolm Watts wrote:
> 
> 
> > Greg, all,
> >              I retuned my work coil this morning (adjusted the
> > primary cap to compensate for a new terminal). I took the opportunity
> > to do a phasing measurement on the first 20 turns or so of the
> > resonator. The primary is a helix. Both coils are wound with the same
> > sense. I left the primary untuned.
> >      Result: The voltage near the base of the resonator is largely in
> > phase with the primary. 
> [snip]
> 
> Hmmm... You and Bert have convinced me about the winding sense.
> Now I am confused as to why you didn't see a significant phase
> shift from pri to sec.
> Were the two coils in fact loosely coupled, and the secondary
> driven at resonance?

k for that coil *as a whole* is 0.12.  As we know, coupling to just 
the bottom is significantly higher than that figure suggests. Imagine 
if the few secondary turns I measured increased in diameter until 
they matched the primary diameter. If you are still not convinced, I 
will be happy to wind a 5/10/20 turn or whatever coil that matches 
primary height and whatever diameter you choose. The same rules are 
obeyed in cored coils, even with significant air gaps (which is one 
reason I can use turns ratio in flyback (twin choke) supplies to 
calculate switch and diode burdens). I don't know what more I can say 
really.
    In answer to the last bit, significant phase shift does occur but 
only progressively as one travels up the resonator winding. The 
voltages are and have to be totally in phase at the base.

To the very best of my knowledge ad experimental work,
Malcolm