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=-2.2 required=5.0 tests=BAYES_00,DNS_FROM_AHBL_RHSBL, HTML_50_60,HTML_MESSAGE 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 tAT9kvOu030372 for ; Sun, 29 Nov 2015 10:46:57 +0100 Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1a2yWE-0006sP-4S for rs_out_1@blacksheep.org; Sun, 29 Nov 2015 09:43:42 +0000 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1a2yWD-0006sE-Pu for rsgb_lf_group@blacksheep.org; Sun, 29 Nov 2015 09:43:41 +0000 Received: from mail-wm0-f53.google.com ([74.125.82.53]) by relay1.thorcom.net with esmtps (TLSv1.2:ECDHE-RSA-AES128-GCM-SHA256:128) (Exim 4.86) (envelope-from ) id 1a2yVD-0002sb-Nf for rsgb_lf_group@blacksheep.org; Sun, 29 Nov 2015 09:43:40 +0000 Received: by wmec201 with SMTP id c201so102803323wme.1 for ; Sun, 29 Nov 2015 01:42:26 -0800 (PST) X-DKIM-Result: Domain=gmail.com Result=Good and Known Domain DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :content-type; bh=CVlyh01yttX3LKGiDDP5ierlzTCUKl8O2e1MKGaJrKM=; b=CAppaT0ax91hPEfHx4ZYfx37ouRbO194rYilS27Fe7DONfMex7Cx4kvafP2eo65X+R oN3QEfC7Jtk0BFpIwu6orpwCprQUltlw76xqb6CWfrLg4cPivNAjk7e3KhhFVgvmjAgy n6DIJSOZ5bidjtu0bck6TvGaF+qxbjsBWsvHNgGexcZYx5thYKmjr6EOd+NMUYgZ0NxP oYFAZuFdyVvT8GaXryC95mysrNhYNyOGn4wfy8dUknPk851GAfgpjwrlxn0JayR/j60v 8jbYTfsf6aOpbiDdXC9C8XSY1m65hJlr5n1LMF/WXLQKl1yXyl9m5WBjRjbQuf4VBPRC cDxg== MIME-Version: 1.0 X-Received: by 10.194.185.6 with SMTP id ey6mr66591463wjc.42.1448790146281; Sun, 29 Nov 2015 01:42:26 -0800 (PST) Received: by 10.28.130.139 with HTTP; Sun, 29 Nov 2015 01:42:26 -0800 (PST) In-Reply-To: References: <56587F40.5070709@posteo.de> <87FFCE57-D2D7-4616-B5E8-B84CD819C685@talktalk.net> <5658E894.6090208@posteo.de> <82B8809C-36E5-4731-8A4B-002BD4465B12@talktalk.net> <5658EE97.2020107@posteo.de> Date: Sun, 29 Nov 2015 09:42:26 +0000 Message-ID: From: Andy Talbot To: rsgb_lf_group@blacksheep.org X-Scan-Signature: 420019f4991fbaa4f653703c21f48617 Subject: Re: 3 phase (was LF: G3KEV) Content-Type: multipart/alternative; boundary=047d7bea40b605f7f00525aabe43 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 10.1.3.10 Status: O X-Status: X-Keywords: X-UID: 5420 --047d7bea40b605f7f00525aabe43 Content-Type: text/plain; charset=UTF-8 If you use two transformers on a 3-phase supply, with the primary windings in a SQRT(3) ratio, one connected in delta, and one in star across the supply; equal value secondaries when rectified will give you 12X ripple instead of the 6X normal achieved though full wave 3-Ph rectification. Unfortunately SQRT(3) is not rational (becuz Euclid sez so!) so any turns ratios will be approximate, hence ripple will be degraded marginally 'jnt On 28 November 2015 at 18:20, mal hamilton wrote: > Andy es Co > 6 phase even better lower ripple. > A car alternator is 3 phase, could easily be 6 > g3kev > > > > *From:* Andy Talbot > *Sent:* Saturday, November 28, 2015 4:26 PM > *To:* rsgb_lf_group@blacksheep.org > *Subject:* Re: 3 phase (was LF: G3KEV) > > What's wrong with that ? > Sounds an excellent idea for a QRO transmitter. 300Hz ripple - much > easier to filter out. > > My 137kHz Tx runs from rectified (single phase) mains - the isolation is > provided in the ferrite output transformer and FET drive pot-core > > A school we once went around with long leads and an AVO identifying > sockets to be found on all three of the phases. That was so that, using > extension leads, we could bring them all into the lab to get a three phase > motor running. Such interesting things could be done in schools in the > 1970's > > Andy G4JNT > > > On 28 November 2015 at 15:52, John Rabson wrote: > >> >> In the early days of 73 kHz I believe a Luxembourg station built a >> transmitter which was powered off full-wave rectified three-phase mains >> without an isolating transformer. NOT the best way of doing things! >> >> John F5VLF >> > --047d7bea40b605f7f00525aabe43 Content-Type: text/html; charset=UTF-8 Content-Transfer-Encoding: quoted-printable
If you use two transformers on a 3-phase supply, with the = primary windings in a SQRT(3) ratio, one connected in delta, and one in sta= r across the supply; equal value secondaries when rectified will give you 1= 2X ripple instead of the 6X normal achieved though full wave 3-Ph rectifica= tion.

Unfortunately SQRT(3) is not rational (becuz Eucli= d sez so!) so any turns ratios will be approximate, hence ripple will be de= graded marginally

'jnt


=


On 28 November 2015 at 18:20, mal hamilton <g3kevmal@= talktalk.net> wrote:
Andy es Co
6 phase even better lower ripple.
A car alternator is 3 phase, could easily be 6
g3kev
=C2=A0
=C2=A0
What's wrong with that ?=20
Sounds an excellent idea for a QRO transmitter.=C2=A0=C2=A0 300Hz ripp= le -=20 much easier to filter out.
=C2=A0
My 137kHz Tx runs from rectified (single phase) mains - the isolation = is=20 provided in the ferrite output transformer and FET drive pot-core
=C2=A0
A school we once went around with long leads and an AVO=C2=A0 identify= ing=20 sockets to be found on all three of the phases.=C2=A0 That was so that, usi= ng=20 extension leads, we could bring them all into the lab to get a three phase = motor=20 running.=C2=A0=C2=A0 Such interesting things could be done in schools in th= e=20 1970's
=C2=A0
Andy G4JNT
=C2=A0
=C2=A0
On 28 November 2015 at 15:52, John Rabson <john.rabson07@gmail.com> wrote:

In the early days of 73 kHz I bel= ieve a Luxembourg=20 station built a transmitter which was powered off full-wave rectified=20 three-phase mains without an isolating transformer. NOT the best way of d= oing=20 things!

John=20 F5VLF

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