Re: Pri-Sec Phasing

To: tesla-at-pupman-dot-com
Subject: Re: Pri-Sec Phasing
From: Tesla List <mod1-at-pupman-dot-com>
Date: Wed, 8 Oct 1997 13:47:21 -0600 (MDT)
Approved: mod1-at-poodle.pupman-dot-com


---------- Forwarded message ----------
Date: Thu, 9 Oct 1997 08:41:05 +1200
From: Malcolm Watts <MALCOLM-at-directorate.wnp.ac.nz>
To: tesla-at-pupman-dot-com
Subject: Re: Pri-Sec Phasing 

Hi Dave,

> From: David Huffman <huffman-at-FNAL.GOV>
> To: Tesla List <tesla-at-pupman-dot-com>
> Subject: Re: Pri-Sec Phasing
> 
> I have to agree with Greg. I know that the voltage polarity is the same,
> that is positive on the start of the primary will make positive on the start
> of the secondary, with the same winding sense. The current on the primary
> would go into the coil to create the positive polarity and the current would
> need to come out of the secondary to cause a positive polarity on a
> resistive load. This still works with the autotransformer analogy since the
> currents sum to zero at any given node.
> Dave H.

The *induced emf* in *both* windings is identical. In both windings, 
induction is attempting to source current from the windings. It 
cannot cause a current flow out of the primary as the power source is 
connected to that winding. If more current came out than went in, it 
would violate a fundamental law of thermodynamics. The induced emf 
causes the polarity in the secondary. The moment the power source is 
disconnected, *both* windings will have their polarties reversed as 
Ed Philips says as the collapsing magnetic field generates an emf 
which is identical if the two windings are closely coupled and have 
the same number of turns.

Malcolm

> From: Greg Leyh <lod-at-pacbell-dot-net>
> To: Tesla List <tesla-at-pupman-dot-com>
> Subject: Re: Pri-Sec Phasing
> 
> Thomas McGahee wrote:
> 
> 
> > Greg,
> > I agree with Malcolm. If what the book said was true, then if you
> > bifilar wound two primary coils and then connected the start of the
> > windings together and then the endings together you would have a
> > current flow between them due to their supposedly opposite
> > polarities. But that just ain't so.
> 
> That is true, assuming both parallel filaments make up a primary
> winding.  But what if one filament was the primary(sourcing power),
> and the other was the secondary(removing power)?
> 
> 
> -GL