Re: Pri/Sec coiling

To: tesla-at-pupman-dot-com
Subject: Re: Pri/Sec coiling
From: Thomas McGahee <tom_mcgahee-at-sigmais-dot-com>
Date: Mon, 3 Feb 1997 17:26:48 -0500
Subscriber: tom_mcgahee-at-sigmais-dot-com Mon Feb 3 21:47:35 1997

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> From: Tesla List <tesla-at-poodle.pupman-dot-com>
> To: Tesla-list-subscribers-at-poodle.pupman-dot-com
> Subject: Pri/Sec coiling
> Date: Sunday, February 02, 1997 8:25 PM
> 
> Subscriber: Rodney.Davies-at-anu.edu.au Sun Feb  2 17:39:43 1997
> Date: Sun, 2 Feb 1997 22:16:55 +1100 (EST)
> From: Rodney Graham Davies <Rodney.Davies-at-anu.edu.au>
> To: tesla-at-pupman-dot-com
> Subject: Pri/Sec coiling
> 
> Hi All,
> 
> I'm going to ask perhaps a silly and obvious answered question, but when 
> winding your primary and secondary, are the windings in the same
direction?
> 
> ie, wind both sec and pri in a clock-wise direction?
> 
> I should be able to derive this from 1st principles of electromagnetic 
> induction, but can't seem to picture it too well.
> 
> The reason why I ask this is that in TC circuit diagrams, the coils (if I

> am correct) are back-to-back w.r.t the primary and secondary coils. I 
> interperate this as being that the coils are wound in opposite directions

> to each other.???
> 
> Then again, this whole idea mightn't really matter...
> Anyway, my puzzling thought for the day...
> 
> Ideas, flames, corrections welcome...
> 
> Thanks guys!
> Catchya later!
> 
> Rod

Rod,
whether a coil is wound clockwise or counter-clockwise depends on how you
look at it :) In other words, if a coil is turned upside down, you have
effectively reversed the windings, haven't you?

As to the effect, I think it does have some bearing, but very minor. The
only way I see it having a large effect is if the coils are interconnected
and the secondary has very few turns. Then you have an autotransformer, and
you want them phased the same. But the difference in most normal coils is
going to be small. It's one of those things that really doesn't matter
enough to worry about. But it was a good question!!

Fr. Tom McGahee