Return-Path: X-Spam-DCC: paranoid 1170; Body=2 Fuz1=2 Fuz2=2 X-Spam-Checker-Version: SpamAssassin 3.1.3 (2006-06-01) on lipkowski.org X-Spam-Level: X-Spam-Status: No, score=-0.7 required=5.0 tests=BAYES_00,DNS_FROM_AHBL_RHSBL, HTML_MESSAGE,RATWARE_GECKO_BUILD,SPF_PASS autolearn=no version=3.1.3 Received: from post.thorcom.com (post.thorcom.com [195.171.43.25]) by paranoid.lipkowski.org (8.13.7/8.13.7) with ESMTP id u2T7KH2A031436 for ; Tue, 29 Mar 2016 09:20:17 +0200 Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1aknoE-0000YW-L5 for rs_out_1@blacksheep.org; Tue, 29 Mar 2016 08:11:26 +0100 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1aknoE-0000YN-3v for rsgb_lf_group@blacksheep.org; Tue, 29 Mar 2016 08:11:26 +0100 Received: from mailfe02.swip.net ([212.247.154.33] helo=swip.net) by relay1.thorcom.net with esmtp (Exim 4.86) (envelope-from ) id 1aknoB-0006pt-Mh for rsgb_lf_group@blacksheep.org; Tue, 29 Mar 2016 08:11:24 +0100 X-T2-Spam-Status: No, hits=0.9 required=5.0 tests=BAYES_50, HTML_MESSAGE Received: from [81.224.101.198] (account cxu-dcw-tyr@tele2.se HELO [192.168.1.9]) by mailfe02.swip.net (CommuniGate Pro SMTP 5.4.4) with ESMTPSA id 660019616 for rsgb_lf_group@blacksheep.org; Tue, 29 Mar 2016 09:11:21 +0200 To: rsgb_lf_group@blacksheep.org References: <8D34C58CF884ECC-1ECC-700FAE@webmail-vd008.sysops.aol.com> <8D34CA56489C6DF-2124-1A7BBA@webmail-vm017.sysops.aol.com> <1D7A91E7-DC1B-4641-95BE-FC096D8155E4@gmail.com> <56EAAF40.20204@tele2.se> From: Johan Bodin Message-ID: <56FA2A98.6030005@tele2.se> Date: Tue, 29 Mar 2016 09:11:20 +0200 User-Agent: Mozilla/5.0 (Windows NT 6.3; WOW64; rv:38.0) Gecko/20100101 Thunderbird/38.7.0 MIME-Version: 1.0 In-Reply-To: X-HELO-Warning: Remote host 212.247.154.33 (mailfe02.swip.net) used invalid HELO/EHLO swip.net - verification failed X-Scan-Signature: 24b65a258fa7a3a87cfdaa03bb2f3176 Subject: Re: LF: 33 Hz QRM Content-Type: multipart/alternative; boundary="------------020602070205020903050706" 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-Scanned-By: MIMEDefang 2.56 on 10.1.3.11 Status: O X-Status: X-Keywords: X-UID: 7507 This is a multi-part message in MIME format. --------------020602070205020903050706 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit That problem can be solved by using a return line and booster transformers that minimises current leakage into surrounding earth: https://library.e.abb.com/public/f1200714de5086c585257d7300287357/1LFI2026%20special%20power%20transformers%20for%20railway%20-%20brochure%20EN.pdf 73 de Johan SM6LKM Den 2016-03-17 kl. 15:18, skrev Andy Talbot: > Is that to minimise skin loss in steel track ? > > UK Third rail is, of course, DC, and I once spent an idle moment > calculating the loss if 50Hz AC were to be used with magnetic iron > conductors. I think I came to the conclusion a 1MW train could > probably travel a few hundred metres before it lost its power supply. > > andy G4JNT > > On 17 March 2016 at 13:21, Johan Bodin > wrote: > > Railway QRG is 16 2/3 Hz in Sweden too. > > 73 de Johan SM6LKM > > John Rabson wrote: > > I seem to recall that some railway systems use at about 16 2/3 > Hz (one third of 50 Hz) for traction. > > ... > > Can someone say whether my recollections are correct, please? > > 73 John F5VLF > > > --------------020602070205020903050706 Content-Type: text/html; charset=utf-8 Content-Transfer-Encoding: 8bit That problem can be solved by using a return line and booster transformers that minimises current leakage into surrounding earth:

https://library.e.abb.com/public/f1200714de5086c585257d7300287357/1LFI2026%20special%20power%20transformers%20for%20railway%20-%20brochure%20EN.pdf

73 de
Johan SM6LKM

Den 2016-03-17 kl. 15:18, skrev Andy Talbot:
Is that to minimise skin loss in steel track ?

UK Third rail is, of course, DC, and I once spent an idle moment calculating the loss if 50Hz AC were to be used with magnetic iron conductors.  I think I came to the conclusion a 1MW train could probably travel a few hundred metres before it lost its power supply.

andy  G4JNT

On 17 March 2016 at 13:21, Johan Bodin <jhbodin@tele2.se> wrote:
Railway QRG is 16 2/3 Hz in Sweden too.

73 de Johan SM6LKM

John Rabson wrote:
I seem to recall that some railway systems use at about 16 2/3 Hz (one third of 50 Hz) for traction.
...
Can someone say whether my recollections are correct, please?

73 John F5VLF



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