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

Re: Space winding



[kch]  See my comments interspersed below.

On Sun, 13 Aug 2000 15:46:59 -0600 "Tesla list" <tesla-at-pupman-dot-com>
writes:
> Original poster: "Malcolm Watts" <M.J.Watts-at-massey.ac.nz> 
> 
> Hi Ken,
>         I think I spot a problem:
> 
> On 11 Aug 00, at 18:25, Tesla list wrote:
> 
> > Original poster: "Kennan C Herrick" <kcha1-at-juno-dot-com> 

<snipped>

[Referencing] the tabulation & commentary given recently by Mark 
> S.
> > Rzeszotarski:
> 
> <snip> 
> > Now...my comments:
> > 
> > 1.  Secondary Q = wL/R where w=2 x pi x resonant frequency, L =
> > inductance & R = effective resistance.  Also, L is proportional to 
> n^2,
> > the square of the quantity of turns, other coil-shape factors 
> being
> > equal.
> > 
> > 2.  From the tabulation, R diminishes, due to diminished
> > proximity-effect, by 1/2 for a tabulation-"w" of 0.5; that is, for 
> the
> > case where the space between turns = the wire diameter.
> > 
> > 2.1  But for that case, n has diminished to 1/2 of the prior 
> quantity and
> > so L diminishes to (1/2)^(1/2) or .25 and also, ohmic R diminishes 
> by 1/2
> > since the total wire length is 1/2 of what it was.
> 
> Why should n have diminished? Are we not talking about the 
> same number of turns?

[kch] Well, that may be the case; I had assumed without thinking about it
(not knowing the source of the table) that the coil shape & size and the
wire-size stayed the same, in which case the turn quantity would vary. 
But maybe the coil size is assumed to change in order to accomodate the
same turn-quantity.  Which is the case?
>  
> > 2.2  Thus, it would seem, total effective R will have diminished 
> to 1/2 x
> > 1/2 = 1/4 of that for the close-wound case.  And thus, the new Q 
> becomes
> > 0.25/0.25 of the old Q, or just the same.
> 
> I have a set of measurements which shows that for the same 
> diameter, height and number of turns, a spacewind produces a 
> higher Q coil. I put them to the list about give years ago.

[kch]  See my later correction to my posting.

<snipped>

Ken Herrick
   

________________________________________________________________
YOU'RE PAYING TOO MUCH FOR THE INTERNET!
Juno now offers FREE Internet Access!
Try it today - there's no risk!  For your FREE software, visit:
http://dl.www.juno-dot-com/get/tagj.