Return-Path: X-Spam-DCC: paranoid 1102; 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=-0.2 required=5.0 tests=BAYES_00,DNS_FROM_AHBL_RHSBL, HTML_40_50,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 u2ILlSOV027739 for ; Fri, 18 Mar 2016 22:47:28 +0100 Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1ah2Bz-0008Iu-CE for rs_out_1@blacksheep.org; Fri, 18 Mar 2016 21:44:23 +0000 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1ah1dp-00074P-Fe for rsgb_lf_group@blacksheep.org; Fri, 18 Mar 2016 21:09:05 +0000 Received: from mout01.posteo.de ([185.67.36.65]) by relay1.thorcom.net with esmtps (TLSv1.2:ECDHE-RSA-AES256-GCM-SHA384:256) (Exim 4.86) (envelope-from ) id 1agdyz-0000wq-Hn for rsgb_lf_group@blacksheep.org; Thu, 17 Mar 2016 19:53:22 +0000 Received: from dovecot03.posteo.de (dovecot03.posteo.de [172.16.0.13]) by mout01.posteo.de (Postfix) with ESMTPS id 01092208D0 for ; Thu, 17 Mar 2016 20:53:16 +0100 (CET) Received: from mail.posteo.de (localhost [127.0.0.1]) by dovecot03.posteo.de (Postfix) with ESMTPSA id 3qQzYR05BZz5vNW for ; Thu, 17 Mar 2016 20:53:14 +0100 (CET) Message-ID: <56EB0B2A.7030708@posteo.de> Date: Thu, 17 Mar 2016 20:53:14 +0100 From: DK7FC User-Agent: Mozilla/5.0 (Windows; U; Windows NT 6.1; de; rv:1.9.1.8) Gecko/20100227 Thunderbird/3.0.3 MIME-Version: 1.0 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> <20160317145911.Horde.1H5cYcrPocF3dL5aHYIO7w3@posti.anvianet.fi> In-Reply-To: X-Scan-Signature: 92b6515a4252c45136e975e6745a1e0d Subject: Re: LF: 33 Hz QRM Content-Type: multipart/alternative; boundary="------------000402010600040507040205" 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: 7403 This is a multi-part message in MIME format. --------------000402010600040507040205 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit The 16 2/3 Hz trace is visible on my VLF remote grabber at http://www.iup.uni-heidelberg.de/schaefer_vlf/DK7FC_VLF_Grabber2.html About 35 dB SNR in 3.8 mHz, to be improved. Although the voltage for the trains is just 15 kV here. I'm watching on the H field though. The distance to the next train line is about 4 km. 73, Stefan Am 17.03.2016 16:37, schrieb PA7EY: > I suppose 16 2/3 is correct (16 1/3 x 3 = 49), according to my > information, they actually use 16.7 in some places these days. > > 73 Ulrich PA7EY > > 2016-03-17 15:59 GMT+01:00 >: > > Hello John, Johan, LF > > 16 2/3 Hz should probably be 16 1/3 Hz, one third of 50 Hz as John > pointed out. > > > Here in OH-land we use 50 Hz for the railways but during my EE > studies, the SM-land railway QRG was also mentioned for two > reasons (hope I remember this right now, it was about 25 years > ago...): > > - A lower frequency was selected to minimize the voltage drop > caused by the series inductance formed by the long overhead lines > supplying the locomotive. > > - Initially 16 1/3 Hz was generated in rotary converters, for > example a 6-pole 50 Hz motor would drive a two pole generator > which gives the required step-down. Rotary converters need > maintenance and so this system was later replaced by > non-mechanical devices such as cyclo-converters or other early > ways of electronic frequency converters that supposedly require > less maintenance. In fact, I think this was the main reason for > bringing up this subject in school. > > > BR > > Paul-Henrik, OH1LSQ > > > > Quoting 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 > > > > > > > --------------000402010600040507040205 Content-Type: text/html; charset=UTF-8 Content-Transfer-Encoding: 8bit The 16 2/3 Hz trace is visible on my VLF remote grabber at http://www.iup.uni-heidelberg.de/schaefer_vlf/DK7FC_VLF_Grabber2.html About 35 dB SNR in 3.8 mHz, to be improved.
Although the voltage for the trains is just 15 kV here. I'm watching on the H field though. The distance to the next train line is about 4 km.

73, Stefan

Am 17.03.2016 16:37, schrieb PA7EY:
I suppose 16 2/3 is correct (16 1/3 x 3 = 49), according to my information, they actually use 16.7 in some places these days.

73 Ulrich PA7EY

2016-03-17 15:59 GMT+01:00 <phl@netikka.fi>:
Hello John, Johan, LF

16 2/3 Hz should probably be 16 1/3 Hz, one third of 50 Hz as John pointed out.


Here in OH-land we use 50 Hz for the railways but during my EE studies, the SM-land railway QRG was also mentioned for two reasons (hope I remember this right now, it was about 25 years ago...):

- A lower frequency was selected to minimize the voltage drop caused by the series inductance formed by the long overhead lines supplying the locomotive.

- Initially 16 1/3 Hz was generated in rotary converters, for example a 6-pole 50 Hz motor would drive a two pole generator which gives the required step-down. Rotary converters need maintenance and so this system was later replaced by non-mechanical devices such as cyclo-converters or other early ways of electronic frequency converters that supposedly require less maintenance. In fact,  I think this was the main reason for bringing up this subject in school.


BR

Paul-Henrik, OH1LSQ



Quoting Andy Talbot <andy.g4jnt@gmail.com>:

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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