X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from fed1rmmtao103.cox.net ([68.230.241.43] verified) by logan.com (CommuniGate Pro SMTP 5.2.14) with ESMTP id 3745553 for flyrotary@lancaironline.net; Sun, 05 Jul 2009 11:26:32 -0400 Received-SPF: none receiver=logan.com; client-ip=68.230.241.43; envelope-from=rv-4mike@cox.net Received: from fed1rmimpo01.cox.net ([70.169.32.71]) by fed1rmmtao103.cox.net (InterMail vM.7.08.02.01 201-2186-121-102-20070209) with ESMTP id <20090705152555.WRKI2915.fed1rmmtao103.cox.net@fed1rmimpo01.cox.net> for ; Sun, 5 Jul 2009 11:25:55 -0400 Received: from wills ([68.105.87.229]) by fed1rmimpo01.cox.net with bizsmtp id CFRs1c00G4wtUdQ03FRuXS; Sun, 05 Jul 2009 11:25:54 -0400 X-VR-Score: 0.00 X-Authority-Analysis: v=1.0 c=1 a=1Gy7GEpFSHoA:10 a=pedpZTtsAAAA:8 a=Ia-xEzejAAAA:8 a=ayC55rCoAAAA:8 a=arxwEM4EAAAA:8 a=QdXCYpuVAAAA:8 a=7g1VtSJxAAAA:8 a=kviXuzpPAAAA:8 a=UretUmmEAAAA:8 a=nUuTZ29dAAAA:8 a=XYllJQ_bBQijX6Hw3GIA:9 a=yNhkT_ndPInwEUSWKu4A:7 a=Tvd6wzjFJ0WusjVMnDCEQydOVSQA:4 a=eJojReuL3h0A:10 a=EzXvWhQp4_cA:10 a=hDPS1QqYg3Atszu5:21 a=3K5O2kFq9zBtgFNA:21 X-CM-Score: 0.00 Message-ID: From: "Mike Wills" To: "Rotary motors in aircraft" References: Subject: Re: [FlyRotary] Re: Overvoltage ? [FlyRotary] Re: Modify Alternator for External Regulator Date: Sun, 5 Jul 2009 08:25:53 -0700 MIME-Version: 1.0 Content-Type: text/plain; format=flowed; charset="Windows-1252"; reply-type=response Content-Transfer-Encoding: 8bit X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2900.5512 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.5579 Charlie, Thanks for this perspective on the risk/benefit ratio of this particular mod. I too fly with an unmodified 1 wire alternator. Or at least I would if I were currently flying. Our airplanes are complicated enough what with EFI, EI, microprocessors, etc., without adding to the complexity (and potential failure modes) by adding "protection" to guard against 1 in a million failures. At least thats my perspective. Mike Wills RV-4 N144MW ----- Original Message ----- From: "Charlie England" To: "Rotary motors in aircraft" Sent: Sunday, July 05, 2009 7:59 AM Subject: [FlyRotary] Re: Overvoltage ? [FlyRotary] Re: Modify Alternator for External Regulator > If you have a controllable circuit breaker or a switchable relay in series > with the B-lead, you can control an over-voltage event. The Aeroelectric > connection offered a 'crowbar' type protector for a while that would > disconnect the B-lead automatically, and if memory serves, Bob Nuckolls > now says that with an effective attention-getter to notify of > over-voltage, the battery will easily damp the voltage to below > damage-causing levels long enough to hit the B-lead disconnect. The only > issue left is whether there is enough combustible material in the > alternator itself to cause any real danger as it runs away, electrically > isolated from the rest of the plane. > > My personal opinion is that each person should carefully evaluate the > relative risks of opening & modifying an inherently extremely reliable > device, at their personal skill level. I spent about half my working life > doing electronics service work and I'm pretty confident in my abilities in > this area. My flying RV-4 (Lyc) has an unmodified '1-wire' alternator. > > Charlie > > Ed Anderson wrote: >> >> Just curious, Todd. When you had your alternator run-a-way, did you have >> a battery or other load on the line. Yes and you are correct, just >> because the odds are 1 in 1000,000 does not mean your 1 couldn’t come up >> tomorrow. And I STILL DON”T use approved plastic fuel cans (or any other >> kind) – one refueling fire was enough {:>). >> >> Thanks for providing that info to the list – now others can see >> alternator over voltage is a possibility with a car alternator and >> without the modification to the field coil circuit may be impossible to >> shut down – short of shutting down your engine. >> >> But, if 60 years of experience is not worth anything regarding >> alternators – then what is experience worth regarding anything. Like just >> about everything else in this “hobby”, you are constantly assessing risk >> (or should be) and I decided the risk of modifying my alternator to >> eliminate the remote risk (base on my experience) of over voltage was >> higher than an over voltage condition. YMMV {:>) >> >> Ed. >> >> Ed Anderson >> >> Rv-6A N494BW Rotary Powered >> >> Matthews, NC >> >> eanderson@carolina.rr.com >> >> http://www.andersonee.com >> >> http://www.dmack.net/mazda/index.html >> >> http://www.flyrotary.com/ >> >> http://members.cox.net/rogersda/rotary/configs.htm#N494BW >> >> >> http://www.rotaryaviation.com/Rotorhead%20Truth.htm >> >> ------------------------------------------------------------------------ >> >> *From:* Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] >> *On Behalf Of *Todd Bartrim >> *Sent:* Sunday, July 05, 2009 3:07 AM >> *To:* Rotary motors in aircraft >> *Subject:* [FlyRotary] Re: Modify Alternator for External Regulator >> >> Yeah, that's what I said too Ed, then it happened to me when I was still >> early in my flight test (on the ground fortunatly). >> However after years of carelessly pouring regular old auto fuel from >> plastic fuel cans, despite all the warnings, I've yet to have a problem. >> But I did hear of a guy that caught his plane on fire this way. ;) >> So yeah, I'm sure it could happen. Hope it doesn't though. It would sure >> ruin my day. >> >> Could it happen, undoubtedly, however, in 60 + years of driving >> automobiles, I have never, never had an alternator run wild – the ones >> that failed, just died. So if I can get by another 60 years {:>), then I’ll >> probably hang up my wings (or who knows perhaps get another pair {:>) >> >> >> >> Ed >> >> Todd >> C-FSTB >> RV9 Turbo13B >> >> >> >> __________ Information from ESET NOD32 Antivirus, version of virus >> signature database 3267 (20080714) __________ >> >> The message was checked by ESET NOD32 Antivirus. >> >> http://www.eset.com >> >> >> >> __________ Information from ESET NOD32 Antivirus, version of virus >> signature database 3267 (20080714) __________ >> >> The message was checked by ESET NOD32 Antivirus. >> >> http://www.eset.com > > > -- > Homepage: http://www.flyrotary.com/ > Archive and UnSub: > http://mail.lancaironline.net:81/lists/flyrotary/List.html >