Return-Path: Received: from rly-mb03.mx.aol.com (rly-mb03.mail.aol.com [172.21.131.161]) by air-mb01.mail.aol.com (v124.15) with ESMTP id MAILINMB011-cfc4a5de07e15d; Wed, 15 Jul 2009 09:58:33 -0400 Received: from post.thorcom.com (post.thorcom.com [193.82.116.20]) by rly-mb03.mx.aol.com (v124.15) with ESMTP id MAILRELAYINMB038-cfc4a5de07e15d; Wed, 15 Jul 2009 09:58:24 -0400 Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1MR4yn-0006bM-8J for rs_out_1@blacksheep.org; Wed, 15 Jul 2009 14:57:05 +0100 Received: from [193.82.116.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1MR4ym-0006bD-Q9 for rsgb_lf_group@blacksheep.org; Wed, 15 Jul 2009 14:57:04 +0100 Received: from smtp817.mail.ird.yahoo.com ([77.238.189.17]) by relay1.thorcom.net with smtp (Exim 4.63) (envelope-from ) id 1MR4yb-0003Dz-F7 for rsgb_lf_group@blacksheep.org; Wed, 15 Jul 2009 14:56:54 +0100 Received: (qmail 93226 invoked from network); 15 Jul 2009 13:56:56 -0000 DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=s1024; d=btinternet.com; h=Received:X-Yahoo-SMTP:X-YMail-OSG:X-Yahoo-Newman-Property:Message-ID:From:To:References:Subject:Date:MIME-Version:Content-Type:Content-Transfer-Encoding:X-Priority:X-MSMail-Priority:X-Mailer:X-MimeOLE; b=F6TmS1BZAhfLDebmGvhF1kSYhVd4RkO56V97tQqsKz6fge2muy15Ccs6rkatxRyDaBi3k40ivuqBm+V8oDfFvggUGRZfT3poI3jX8js3o+EVMEhQOlXpGKWsBzxL5Wk2x6xWEBE3nUo/1Ji6nhiY2IcbjQeTiKLWOxdNWUSyaMc= ; Received: from unknown (HELO Lark) (alan.melia@213.122.40.190 with login) by smtp817.mail.ird.yahoo.com with SMTP; 15 Jul 2009 13:56:55 -0000 X-Yahoo-SMTP: KHdpK2OswBBXlm4uxknbEiS4uYdJoGknHN90u4K8__lTafnafZg- X-YMail-OSG: Wh3NCn4VM1kp084TFHokgUk2mhezQ.TgpVsv2Sn8iX8aIXQ1t98fjcfEkv.isLEwKmiE317DGKwLMGYNRRc41dWNDRxXsjw0jI9JmYareIysCJoOkGvDFXREAjYvr.kMN3MS1DHC.puNhdyrnCmI8hviqRFpRLYrOZREy0g4LRZvnutIA7XCyZo1gA3jh1IN_WGbJUbtdUQ1P1ANtW1q.Ud6Oioyp4b8p0zwiLb4hRVCrfBbxnohE2bTLjxMM5XwEL0eCH42gabm4guM5ShkFl1n6Aq4tLOhP.RsftjhdmoGAV..S2t2KFcO_XK0mezsZMvT3uUQZQgJpKFLCuCUu_e825foNiEIbq8qP.aHzg-- X-Yahoo-Newman-Property: ymail-3 Message-ID: <003501ca0554$292717a0$0900a8c0@AM> From: "Alan Melia" To: References: Date: Wed, 15 Jul 2009 14:57:11 +0100 MIME-Version: 1.0 X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2600.0000 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2600.0000 X-Karma: unknown: DomainKey-Status: good (testing) X-Spam-Score: 0.0 (/) X-Spam-Report: autolearn=disabled,none Subject: Re: Re: LF: Microwave oven transformers Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit 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=none 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-IP: 193.82.116.20 Hi all, I am very please to see not everyone sticks to a 12 volt maximum supply voltage :-)) One though that occurs to me is that if one side of the MO transformer is grounded in oven service........one ought to check that the winding as a whole is sufficiently well insulated from ground to stand floating 2kV above ground. There may not be the same clearance /insulation on the grounded end of the secondary as the intended high-voltage end?? On the other hand it might be quite OK. I have a certain cynicism about "consumer designs". Alan G3NYK ----- Original Message ----- From: To: Sent: Wednesday, July 15, 2009 2:34 PM Subject: Re: Re: LF: Microwave oven transformers These special transformers need the magnetic bypass because a magnetron looks (as a load) like a Z diode. So they are powered, more or less, with a constant current source rather than a constant voltage source. In other words, the "generator" (transformer) must have a large source impedance, and that's what the magnetic bypass in the 'former does. Cheers, Wolf .