Re: Charging Inductor Construction (fwd) / Induction Coils (fwd)

["Tesla list" <tesla@xxxxxxxxxx>]

---------- Forwarded message ----------
Date: Sun, 28 Oct 2007 10:33:50 +0100
From: Kurt Schraner <k.schraner@xxxxxxxxxxx>
To: Tesla list <tesla@xxxxxxxxxx>
Subject: Re: Charging Inductor Construction (fwd) / Induction Coils

Tesla list wrote:
> ---------- Forwarded message ----------
> Date: Sat, 27 Oct 2007 12:02:54 -0700
> From: Ed Phillips <evp@xxxxxxxxxxx>
> To: Tesla list <tesla@xxxxxxxxxx>
> Subject: Re: Charging Inductor Construction (fwd)
>
> Hi Crispy,
>
> for 50mH you might do it with an "air-core" inductor, composed of a
> number of "pies" as seen for my induction coils on:
>
> http://home.datacomm.ch/k.schraner/induc_build.htm";
>
> Kurt:
>
> Thanks for these pictures and the comment that "wild wound" (we
> here call it scramble wound but obviously the same) pies can withstand
> that much voltage.  I suspect that is with pretty careful winding
> however. What are the dimensions of those pies?  I can scale
> approximately from the pictures but interested in the actual values.
> This looks like an excellent project for someone with a lot of spare
> time!  The picture of all of the pies spread out on a table really
> gives a good idea of the magnitude of the job.
>
> Ed

Hello Ed,

thanks for the answer and for giving me the term "scramble wound", 
correcting my very limited english-vocabulary :-). The dimensions of _one_ 
pie are as follows:

ID of the (netto) winding:  85mm
OD of the (netto) winding: 175mm
Width (netto) of winding:    9mm
Wire: copper 0.45mm; insulated 0.53mm
Number of turns: 1600
Air inductance of the pie: 369mH(calc.); 377mH(measured)
The former is as follows:
ID:  73mm
OD: 185mm
Width (outside): 13mm

Some data of the _assembled_ secondary are as follows:
(in the final assembly are 26pies only, instead of 28)
Copper weight:   ~24kg
length of wire:  ~17km
Air inductance:  ~66H
Iron Inductance: ~1970H

(All of the data [and more] are contained in a design-Excel for my induction 
coils, which is available off-list).

Obviously winding this secondary is more challenging than winding a TC 
secondary. A winding rig, involving my hand drill was a condition (see 
http://home.datacomm.ch/k.schraner/13_09_01ind01a.jpg
...sorry for the low quality picture). When winding, one is getting used to 
apply quite regular distribution of the turns within the winding space. 
Anyway: winding was less of a problem than obtaining and making the formers, 
and the paraffin impregnation of the pies. Well, I'm an old, and retired 
guy, taking the time for it.

BTW: the experiance, gained from this induction coil, helped to construct 
some smaller ones, whom I'd like to comment some time on my other website:

http://twfpowerelectronics.com/%7Ekurt/InductionCoils/induction_coils2.html

One of the small coils is at:

http://twfpowerelectronics.com/%7Ekurt/InductionCoils/Farm/10_smallHomebrew376k.jpg

Best regards
Kurt