Received: from post.thorcom.com (post.thorcom.com [195.171.43.25]) by mtain-mk01.r1000.mx.aol.com (Internet Inbound) with ESMTP id 56D1638000511; Tue, 30 Aug 2011 09:28:44 -0400 (EDT) Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1QyOM6-0007FK-LK for rs_out_1@blacksheep.org; Tue, 30 Aug 2011 14:27:54 +0100 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1QyOM6-0007FB-4x for rsgb_lf_group@blacksheep.org; Tue, 30 Aug 2011 14:27:54 +0100 Received: from mail-pz0-f42.google.com ([209.85.210.42]) by relay1.thorcom.net with esmtp (Exim 4.63) (envelope-from ) id 1QyOM3-0005CZ-K5 for rsgb_lf_group@blacksheep.org; Tue, 30 Aug 2011 14:27:54 +0100 Received: by pzk37 with SMTP id 37so10310385pzk.1 for ; Tue, 30 Aug 2011 06:27:45 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :content-type; bh=MfJvGc5hwW5A2oNVgwCueUe171GGgUSdHJJkHFCiaF0=; b=fye/Ijuo4WaFfP+cb5fSU0s+VYQOb+pPv++YqkJgHiIPjjgzdfWxMwVIWEUhzP6UMu givB9HPorztcwqw41QKIDHH+7s+wJ9bftFSq25ip79E4LhQQ6/AzFnvcIse90Hojkfiz 4CmSer6M66rCw0t9f5+P/kfl/xDK3GVojnXNs= MIME-Version: 1.0 Received: by 10.142.141.7 with SMTP id o7mr2980666wfd.268.1314710865155; Tue, 30 Aug 2011 06:27:45 -0700 (PDT) Received: by 10.142.188.7 with HTTP; Tue, 30 Aug 2011 06:27:45 -0700 (PDT) In-Reply-To: <4E5CE126.2090203@iup.uni-heidelberg.de> References: <4E5CE126.2090203@iup.uni-heidelberg.de> Date: Tue, 30 Aug 2011 14:27:45 +0100 Message-ID: From: Roger Lapthorn To: rsgb_lf_group@blacksheep.org X-Spam-Score: 0.0 (/) X-Spam-Report: autolearn=disabled,HTML_MESSAGE=0.001 Subject: Re: LF: HF Litz wire for TX coils? Content-Type: multipart/alternative; boundary=000e0cd32e9419962f04abb8faaf X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on post.thorcom.com X-Spam-Level: X-Spam-Status: No, hits=0.0 required=5.0 tests=HTML_MESSAGE autolearn=no version=2.63 X-SA-Exim-Scanned: Yes Sender: owner-rsgb_lf_group@blacksheep.org Precedence: bulk Reply-To: rsgb_lf_group@blacksheep.org X-Listname: rsgb_lf_group X-SA-Exim-Rcpt-To: rs_out_1@blacksheep.org X-SA-Exim-Scanned: No; SAEximRunCond expanded to false x-aol-global-disposition: G X-AOL-SCOLL-SCORE: 0:2:426988032:93952408 X-AOL-SCOLL-URL_COUNT: 0 X-AOL-SCOLL-AUTHENTICATION: mail_rly_antispam_dkim-m003.1 ; domain : gmail.com DKIM : pass x-aol-sid: 3039ac1d61854e5ce58c2bf5 X-AOL-IP: 195.171.43.25 X-AOL-SPF: domain : blacksheep.org SPF : none --000e0cd32e9419962f04abb8faaf Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable Yes please don't burn down the institute Stefan! 73s Roger G3XBM 2011/8/30 Stefan Sch=E4fer > LF, > > I plan to build a rather compact LF TX coil with reduced losses. Now i > think about using a bigger enamelled wire (currently using ordinary > loudspeaker cable). A local distributor (http://www.elnatrafo.de/) > offers 2mm diameter enamelled copper wire for about 10 EUR/kg which is a > fair price. The current wire is 0.75mm^2, so about 1 mm diameter. > > HF Litz wire may have lower losses at 136 k but what about the current > capability / ampacity? I searched for some data of the litz wire i used > for the ferrite antenna: A litz wire of 120*0.1 mm > (http://www.reichelt.de/index.**html?ACTION=3D3;ARTICLE=3D57209;** > SEARCH=3DCLI%20200%2F120 > ) > is 0.943 mm^2 but handles just 3.36 A. > > A single wire with 2mm diameter (assuming 0.18mm skin depth at 136 kHz) > has a effective cross section area of 1.02 mm^2, so about the same as > the Litz wire i mentioned. But the single wire is more robust, cheaper > and easier to wind. Also the heat transfer could be better with a single > wire when using a PVC tube for the coil. > > I need about 2.9 mH for resonating at 137 kHz (yes, Mal, we know, you > have below 1 mH our youzr inv-L). This could be achieved by using a 20 > cm diameter tube and about 120m of wire. http://dl.dropbox.com/u/** > 19882028/LF/coil%**20calculation.png > > Any comments or suggestions? > > 73, Stefan/DK7FC > > PS: What do you think about a coil body out of glass? I have to take > very special care here not to burn down the institute but i want to > remote control the system, so mostly i cannot watch the coil and have no > XYL walking arround in the garden, telling me if something begins to > smell ;-) > > > > --=20 http://g3xbm-qrp.blogspot.com/ http://www.g3xbm.co.uk http://www.youtube.com/user/g3xbm https://sites.google.com/site/sub9khz/ --000e0cd32e9419962f04abb8faaf Content-Type: text/html; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable Yes please don't burn down the institute Stefan!

73s
Roger G3= XBM

2011/8/30 Stefan Sch=E4fer <Stefa= n.Schaefer@iup.uni-heidelberg.de>
LF,

I plan to build a rather compact LF TX coil with reduced losses. Now i
think about using a bigger enamelled wire (currently using ordinary
loudspeaker cable). A local distributor (http://www.elnatrafo.de/)
offers 2mm diameter enamelled copper wire for about 10 EUR/kg which is a fair price. The current wire is 0.75mm^2, so about 1 mm diameter.

HF Litz wire may have lower losses at 136 k but what about the current
capability / ampacity? I searched for some data of the litz wire i used
for the ferrite antenna: A litz wire of 120*0.1 mm
(http://www.reichelt.de/index.<= /u>html?ACTION=3D3;ARTICLE=3D57209;SEARCH=3DCLI%20200%2F120)
is 0.943 mm^2 but handles just 3.36 A.

A single wire with 2mm diameter (assuming 0.18mm skin depth at 136 kHz)
has a effective cross section area of 1.02 mm^2, so about the same as
the Litz wire i mentioned. But the single wire is more robust, cheaper
and easier to wind. Also the heat transfer could be better with a single wire when using a PVC tube for the coil.

I need about 2.9 mH for resonating at 137 kHz =A0(yes, Mal, we know, you have below 1 mH our youzr inv-L). This could be achieved by using a 20
cm diameter tube and about 120m of wire. http://dl.dropbox.co= m/u/19882028/LF/coil%20calculation.png

Any comments or suggestions?

73, Stefan/DK7FC

PS: What do you think about a coil body out of glass? I have to take
very special care here not to burn down the institute but i want to
remote control the system, so mostly i cannot watch the coil and have no XYL walking arround in the garden, telling me if something begins to
smell ;-)






--
http://g3xbm-qrp.blogspot.com/http://www.g3xbm.co.u= k
http://www.= youtube.com/user/g3xbm
https://sites.google.com/site/sub9khz/

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