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[82.70.254.222]) by smtp.gmail.com with ESMTPSA id 187sm16965163wmu.41.2018.05.08.11.43.23 (version=TLS1 cipher=AES128-SHA bits=128/128); Tue, 08 May 2018 11:43:23 -0700 (PDT) Date: Tue, 8 May 2018 19:43:22 +0100 From: Chris Wilson X-Priority: 3 (Normal) Message-ID: <302337153.20180508194322@gmail.com> To: Andy Talbot In-Reply-To: References: <376794419.20180503144640@gmail.com> MIME-Version: 1.0 X-Spam-Score: 0.0 (/) X-Spam-Report: Spam detection software, running on the system "relay1.thorcom.net", has NOT identified this incoming email as spam. The original message has been attached to this so you can view it or label similar future email. If you have any questions, see the administrator of that system for details. Content preview: Hello Andy, Sorry for the late reply, work intervened and the grass grew to the level I had promised my wife it would never again get to, so I have been limping the old ride on around praying it would not throw its toys from its pram again in protest at the strain ;) I am assimilating the maths, slowly, very slowly. is there any visual way to see if an output transformer is saturating? I wound a few loose turns around a 5kV transformer to look at the patterns when running it near its input voltage and output current limit, some years ago. No maths involved, which is of great comfort to me. Thanks for your detailed reply. [...] Content analysis details: (0.0 points, 5.0 required) pts rule name description ---- ---------------------- -------------------------------------------------- 0.0 FREEMAIL_FROM Sender email is commonly abused enduser mail provider (dead.fets[at]gmail.com) 0.0 T_DKIM_INVALID DKIM-Signature header exists but is not valid X-Scan-Signature: a6b6ffaf48fdddf1ed5c25dc4bf03ee1 Subject: Re: LF: How can you tell if a Class D amp output transformer is starting to saturate? Content-Type: text/plain; charset=utf-8 X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on post.thorcom.com X-Spam-Level: X-Spam-Status: No, hits=0.8 required=5.0 tests=PRIORITY_NO_NAME 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 Content-Transfer-Encoding: 8bit X-MIME-Autoconverted: from quoted-printable to 8bit by klubnl.pl id w48IpVJ9031979 Hello Andy, Sorry for the late reply, work intervened and the grass grew to the level I had promised my wife it would never again get to, so I have been limping the old ride on around praying it would not throw its toys from its pram again in protest at the strain ;) I am assimilating the maths, slowly, very slowly. is there any visual way to see if an output transformer is saturating? I wound a few loose turns around a 5kV transformer to look at the patterns when running it near its input voltage and output current limit, some years ago. No maths involved, which is of great comfort to me. Thanks for your detailed reply. Thursday, May 3, 2018, 3:00:36 PM, you wrote: > By measuring the voltage across the winding using a scope, then > seeing what Bmax is using teh equation > Vrms = 4.44.F.N.A.B > F Hz     N turns   A core cross-sectional area in metres^2    B tesla > If B works out higher than about 0.1 for a ferrite core, then you are approaching saturation > Andy > www.g4jnt.com -- Best regards, Chris mailto:dead.fets@gmail.com