RE: Space winding question

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "John H. Couture by way of Terry Fritz <twftesla-at-uswest-dot-net>" <couturejh-at-worldnet.att-dot-net>


Stan -

As Terry showed in another post your question can be answered with a few
manual calculations. However, it is easier to use a TC computer program like
the JHCTES program. An on-line Ver 3.2 of this program can be found at my
web site

   http://home.att-dot-net/~couturejh

For your question enter in the secondary inputs
   Rad       6.00
   Turns     1000
   TPI       18.5   1000/54  (closewound)
   Sec term     0
   Click "Calculate" or "Calculated etc." and the resonant operating
frequency of 138.67 Khz appears in the upper right corner of the screen. To
print click on "File - Print".

For the space wound coil change only the TPI to 16.7 = 1000/60
Click "Calculate" which gives 140.62 Khz

Terry's resonant frequencies are slightly different because he used a
different Medhurst equation for the coil self capacity.

There is another type of question that is much more difficult for the expert
to answer but is easily answered by using a computer.
The question "How many turns would be required on the space wound coil to
give the same resonant frequency as the closewound coil?"
This requires an iterative type solution and "many many" repeat manual
calculations. Several of the variables are changing at the same time
including the coil inductance, coil self capacity, etc.

To find the solution with the computer leave the TPI at 16.7 and vary only
the number of turns until the 138.21 Khz shows in the outputs at the upper
right of the screen. Several other new outputs will also be shown. You will
find that the answer is 1020 turns.

There are dozens of TC questions that are difficult for anyone to answer but
you can find the answer with a computer and the right program.

John Couture

------------------------------

-----Original Message-----
From: Tesla list [mailto:tesla-at-pupman-dot-com]
Sent: Friday, March 09, 2001 7:59 PM
To: tesla-at-pupman-dot-com
Subject: Space winding question


Original poster: "D.Wightman by way of Terry Fritz <twftesla-at-uswest-dot-net>"
<dwightman-at-mmcable-dot-com>

I was wondering who could answer my question about space wound secondarys.
Lets
say that you have a 12 inch secondary form, and you wind it with # 18
wire,"non
space wound" with 1000 turns. The H/D ratio turns out to be 4.5 to 1. Then
lets
say that you decide to wind another 12 inch "space wound" with 1000 turns,
and
the H/D ratio comes out to 6 to 1. Would the two coils resonate at the same
frequency? In other words would the tank circuit see the two coils as having
the same characteristics ? I am really stumped on this one.
                                                                 Thanks
everyone.


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"Nature has stored up in the universe infinite energy.
The eternal recipient and transmitter of this infinite energy is the ether".
                                       Nikola Tesla. May 20, 1891.