X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml@lancaironline.net Date: Fri, 01 Feb 2008 22:23:49 -0500 Message-ID: X-Original-Return-Path: Received: from smtp119.sbc.mail.sp1.yahoo.com ([69.147.64.92] verified) by logan.com (CommuniGate Pro SMTP 5.2.0) with SMTP id 2710384 for lml@lancaironline.net; Fri, 01 Feb 2008 00:38:19 -0500 Received: (qmail 64232 invoked from network); 1 Feb 2008 05:38:14 -0000 DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=s1024; d=sbcglobal.net; h=Received:X-YMail-OSG:X-Yahoo-Newman-Property:Message-ID:From:To:Subject:Date:MIME-Version:Content-Type:X-Priority:X-MSMail-Priority:X-Mailer:X-MimeOLE; b=N9GhDur5QvvUM1UUAwkti2vPdE3qh/esfq8yg0XUgaVDjHSyom6WBAW9mQQM2q+DtagvXrClG/HzUYlBHTuss29IRIQuE62c0l7QERrzHgwS7ZPCKHfFtqXibghH0zsBcJXNVJJPemi4JTPG/exkSh3U+pa0AUlykiOvv6XRPAE= ; Received: from unknown (HELO Computerroom) (elippse@sbcglobal.net@75.5.198.25 with login) by smtp119.sbc.mail.sp1.yahoo.com with SMTP; 1 Feb 2008 05:38:14 -0000 X-YMail-OSG: oXxPOFsVM1kKJoti0lBL22gtPG5Wufc6p0Myf8L5ny_5pzHTDxzQ454_EAMXLAVVg3rAC7vOZw-- X-Yahoo-Newman-Property: ymail-3 X-Original-Message-ID: <001801c86494$a4738270$cf950f4b@Computerroom> From: "Paul Lipps" X-Original-To: "Marv Kaye" Subject: Overvoltage X-Original-Date: Thu, 31 Jan 2008 21:38:13 -0800 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0015_01C86451.9549F600" X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2900.3138 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.3198 This is a multi-part message in MIME format. ------=_NextPart_000_0015_01C86451.9549F600 Content-Type: text/plain; charset="Windows-1252" Content-Transfer-Encoding: quoted-printable Let's look at why you can have an overvoltage condition existing with an = alternator. The cause of that is an excessive field current, along with = high rpm. An alternator has an output which is V =3D rad/sec x field = current. What the typical overvoltage protection device does is put a = short on the field circuit breaker, causing it to pop, removing the = source of field current. If your problem stems from a VR inside the = alternator which puts max current on the field, then you will have to = isolate that somehow. Otherwise you have to look at an external VR = having a problem or a short from the alternator output to the field, = which is one of the more unlikely events. If you keep the rpm low then = you may not be able to produce an OV even with max field current. But at = high rpm, the alternator can put out in excess of 100V; there used to be = a device that you put on your car to get over 100V DC to run = series-wound saws and drills. This either gave max field and you = regulated the output voltage by varying the rpm, or you set the rpm high = and you had a VR which regulated it for 110V-120V. ------=_NextPart_000_0015_01C86451.9549F600 Content-Type: text/html; charset="Windows-1252" Content-Transfer-Encoding: quoted-printable
Let's look at why you can have an overvoltage = condition=20 existing with an alternator. The cause of that is an excessive field = current,=20 along with high rpm. An alternator has an output which is V =3D rad/sec = x field=20 current. What the typical overvoltage protection device does is put a = short on=20 the field circuit breaker, causing it to pop, removing the source of = field=20 current. If your problem stems from a VR inside the alternator which = puts max=20 current on the field, then you will have to isolate that somehow. = Otherwise you=20 have to look at an external VR having a problem or a short from the = alternator output to the field, which is one of the more unlikely = events. If you=20 keep the rpm low then you may not be able to produce an OV even with max = field=20 current. But at high rpm, the alternator can put out in excess of 100V; = there=20 used to be a device that you put on your car to get over 100V DC to run=20 series-wound saws and drills. This either gave max field and you = regulated=20 the output voltage by varying the rpm, or you set the rpm high and you = had a VR=20 which regulated it for 110V-120V.
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