X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from cartier.micfo.com ([67.15.58.72] verified) by logan.com (CommuniGate Pro SMTP 5.0c2) with ESMTPS id 716595 for flyrotary@lancaironline.net; Fri, 09 Sep 2005 09:33:30 -0400 Received-SPF: none receiver=logan.com; client-ip=67.15.58.72; envelope-from=bob@bob-white.com Received: from bgp01386375bgs.brodwy01.nm.comcast.net ([68.35.160.229]:32974 helo=quail) by cartier.micfo.com with smtp (Exim 4.50) id 1EDizh-0007AW-VB for flyrotary@lancaironline.net; Fri, 09 Sep 2005 08:32:42 -0500 Date: Fri, 9 Sep 2005 07:32:33 -0600 From: Bob White To: "Rotary motors in aircraft" Subject: Re: [FlyRotary] Re: Overvoltage control (help Ed A) Message-Id: <20050909073233.dab1336c.bob@bob-white.com> In-Reply-To: References: X-Mailer: Sylpheed version 2.1.1 (GTK+ 2.4.9; i686-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-PopBeforeSMTPSenders: bobw2,rlwhite,sales@roblinphoto.com,webmaster@bearnutupholstery.com X-Antivirus-Scanner: Clean mail though you should still use an Antivirus X-AntiAbuse: This header was added to track abuse, please include it with any abuse report X-AntiAbuse: Primary Hostname - cartier.micfo.com X-AntiAbuse: Original Domain - lancaironline.net X-AntiAbuse: Originator/Caller UID/GID - [47 12] / [47 12] X-AntiAbuse: Sender Address Domain - bob-white.com X-Source: X-Source-Args: X-Source-Dir: The likelihood of the alternator catching fire is pretty remote. With the B lead open, there is no current in the output windings, so no heat. The field windings could be in a runaway condition where more voltage produces more current which produces more voltage. The field winindings would get hot - till they fail, then no more heat. The downside of this type of regulator failure is destruction of the alternator. With the external regulator and an OVP module, you can pop a circuit breaker to insure interruption the field current. Bob W. On Fri, 9 Sep 2005 07:34:45 -0500 "Mark R Steitle" wrote: > I first explored this issue after Bob Knuckols expressed a dislike of > internally regulated alternators...because they can fail in such a way > that you cannot shut them down. Yes, you can interrupt the "B" lead, > but this will not shut down the alternator. I imagine it could get hot > enough to self-destruct and possibly catch fire. > -- http://www.bob-white.com N93BD - Rotary Powered BD-4 (real soon) Prewired EC2 Cables - http://www.roblinphoto.com/shop/