X-Junk-Score: 0 [] X-Cloudmark-Score: 0 [] X-Cloudmark-Analysis: v=2.2 cv=QoAc5h6d c=1 sm=1 tr=0 a=4NlNMipMRxsRUqezHI480A==:117 a=ToaUX8feg4eQ4GlCfSXS5A==:17 a=x7bEGLp0ZPQA:10 a=A-0mRrAPPO4A:10 a=dapMudl6Dx4A:10 a=r77TgQKjGQsHNAKrUKIA:9 a=eRLigfuSAAAA:8 a=on22okXAAAAA:8 a=Ia-xEzejAAAA:8 a=7g1VtSJxAAAA:8 a=_6GpL_ENAAAA:8 a=ZmIrPTrPyXCmpfhS198A:9 a=QEXdDO2ut3YA:10 a=Qa1je4BO31QA:10 a=gvSQh4r-fQ0A:10 a=4PR2P7QzAAAA:8 a=evSqD-ya8GdxE8_aiyIA:9 a=FAn2b1IkWy_zRO_K:21 a=_W_S_7VecoQA:10 a=BfhXYjFvZD4iae-mNffo:22 a=NPqpj5bUEVj9vR1HIonK:22 a=Urk15JJjZg1Xo0ryW_k8:22 a=grOzbf7U_OpcSX4AJOnl:22 a=4dqwQCo7Po2mVW515mGf:22 From: "Charlie England ceengland7@gmail.com" Received: from mail-yb0-f170.google.com ([209.85.213.170] verified) by logan.com (CommuniGate Pro SMTP 6.2.6) with ESMTPS id 11469118 for flyrotary@lancaironline.net; Thu, 02 Aug 2018 12:18:57 -0400 Received-SPF: pass receiver=logan.com; client-ip=209.85.213.170; envelope-from=ceengland7@gmail.com Received: by mail-yb0-f170.google.com with SMTP id x15-v6so1321902ybm.2 for ; Thu, 02 Aug 2018 09:18:58 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=subject:to:references:from:message-id:date:user-agent:mime-version :in-reply-to:content-language; bh=xcm4x/9FwnnXdecBDcILnwRhSrq7PtjX3jNIuZdb4cY=; b=U1jQZMGc2/y71SrjFCbpOqR2dAcN4A2NPcHeOmzYkOxn4GWDtdw16AswME1dzYYxTN 5PcCwFOR1vdeCdW2d6Dc/2leXXXdyoX1BCDK6Q9B5lG4dTmCzW3njXhYvuxUU2A2hiLA IFhY12LPKEd5sfkD0ZXnR60VPmasMxLPRnwgSroyVGFc1gUxzrtACRCBWXF6vFoS5YNh Tn2tPRzwrj0DhgAqupMo7puLDaHolIJCrD0G7jvhCKLDJ+RMVm/NWorYSnTimbjWIF35 aSOJRJGQvMgSoCXkuwgiyM76ULIScsq+RpdFfcfNrwBByA6QMUO5/OYTwlYRo0LD0NJX RxPg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:to:references:from:message-id:date :user-agent:mime-version:in-reply-to:content-language; bh=xcm4x/9FwnnXdecBDcILnwRhSrq7PtjX3jNIuZdb4cY=; b=VxE4dBpjv3GHWVw5PGXcAc9vsLHvnBSDvR+mVTGWHcFkMFnlFa+N1j7bz+1HA/qnCO dE1wQtmXv5dWwqFohQmSYu2XWl67NZDlgA4L2gmwlkNId5MuGM7Y5YYXkU7/bsYE/NiV HHKPEPxw7rPj0fmPswXRo3KSJo9KrgGiMGrmcTHqVMT1WT3Sc4PaJkIWr92oHK2jZIU0 MV0I07SJw03fPHaUF0eB0k5fdC15DIcoi5sSHnKXgCEl+hj5v/Ur/sNvNwW6G+UDhK7c Xx/1B8etj4NN5Hv5MLmth0V2nkid4ucH/AVvM9HZTXWo7/ZD5sJ5nJaAO6Rrk3S+HOIG RoCA== X-Gm-Message-State: AOUpUlEbve3DISCcBudNrRz/c7FY8M9dkWSbkHA8dJ+9SO7vJg1sU7Vr owqKdPLI8O/io/G9RS9xfC2E+K0+ X-Google-Smtp-Source: AAOMgpfcMEYrrZbo3X9yFZXlGiOuueLGItkhmzSxGqTmcPBdDM0P3RvIfk9XIuavelqfM6AdiC/yJw== X-Received: by 2002:a81:4310:: with SMTP id q16-v6mr82072ywa.413.1533226719958; Thu, 02 Aug 2018 09:18:39 -0700 (PDT) Return-Path: Received: from [192.168.10.217] ([166.137.96.3]) by smtp.googlemail.com with ESMTPSA id y133-v6sm2787255ywy.31.2018.08.02.09.18.38 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 02 Aug 2018 09:18:39 -0700 (PDT) Subject: Re: [FlyRotary] Re: Alternator Damaged - Internal Short To: Rotary motors in aircraft References: Message-ID: <04d45345-586e-b73d-e0f8-655067d84901@gmail.com> Date: Thu, 2 Aug 2018 11:19:53 -0500 User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:52.0) Gecko/20100101 Thunderbird/52.9.1 MIME-Version: 1.0 In-Reply-To: Content-Type: multipart/alternative; boundary="------------FEC620BD08B1EE2D38AF52E0" Content-Language: en-US X-Antivirus: Avast (VPS 180802-2, 08/02/2018), Outbound message X-Antivirus-Status: Clean This is a multi-part message in MIME format. --------------FEC620BD08B1EE2D38AF52E0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit I don't remember electrical issues being discussed much on this list, but they probably should be discussed more.  :-)  I'm a big believer in the Matronics Aeroelectric list. The 'patriarch' of the list is Bob Nuckolls, who has at least 4 decades of experience in the certified a/c world, and wrote 'the book' on homebuilt electrical systems. No homebuilt should be wired without it. :-) He sells printed copies, or you can download it for free from the Aeroelectric web site. Protecting B-leads has been discussed quite a bit over there. Something that any circuit designer would say is that the circuit protection protects the *wire*; not any devices in the circuit. The alternator B-lead can be confusing, since the alternator is supplying power. BUT, the wire should be sized to handle anything that the alternator can throw at it. (Alternators are self-limiting; they can only deliver a slight amount more current than their rating.) /So the alternator can never damage the wire/. However, the battery *can* damage the wire, as Jeff discovered. So....B-lead protection needs to be on the *battery end* of the B-lead. Not at the battery itself, of course, unless the B-lead goes all the way to the battery terminal. But where ever the smaller sized B-lead is terminated, closest to the battery. Sizing the protection could vary a bit, depending on what type of device is used. Some fuses are quite fast acting, and need to be up-sized quite a bit to avoid nuisance trips, but a lot of the higher current 'current limiter' (hate that term) devices have quite long time constants and can be sized at the rating of the wire itself. Jeff, congrats on getting it on the ground quick. If the relay hadn't burned open, the battery would have been depleted pretty quickly. Did your low voltage monitor light up? Charlie On 8/2/2018 10:44 AM, Andrew Martin andrew@martinag.com.au wrote: > My fuse is 100amp mounted close to the B post on an 80 amp alternator > > Andrew > > > > > On Thu, Aug 2, 2018 at 11:39 PM, Jeff Whaley jwhaley@datacast.com > > wrote: > > Bobby, no I did not fuse the B lead.  What amperage would it be if > installed? > Jeff > > Jeff, > > Do you have a fuse in the B lead? > > Bobby > > -----Original Message----- > From: Jeff Whaley > Sent: August-02-18 10:41 AM > To: Rotary motors in aircraft > Subject: Alternator Damaged - Internal Short > > Last Thursday I decided to try my cooling on a hot day 32C (90F); > orbiting the airport, the cooling wasn't too bad but while waiting > for the temps to stabilize I smelled smoke so landed immediately.  > Saw a bit of smoke exiting the oil cooler plenum so thought I was > baking some fiberglass. > On the weekend I did a more thorough inspection and found the > battery mains cable burned where attached to my alternator cut-out > relay and the relay fried to the point that the input terminal was > loose.  The connections stayed in place but open-circuited the > relay - so the engine never skipped a beat and I was unaware there > was an electrical problem at the time. Only reporting this now as > it took me a while to get the alternator tested. > Jeff > > -- > Homepage: http://www.flyrotary.com/ > Archive and UnSub: > http://mail.lancaironline.net:81/lists/flyrotary/List.html > > > --- This email has been checked for viruses by Avast antivirus software. https://www.avast.com/antivirus --------------FEC620BD08B1EE2D38AF52E0 Content-Type: text/html; charset=utf-8 Content-Transfer-Encoding: 8bit
I don't remember electrical issues being discussed much on this list, but they probably should be discussed more.  :-)  I'm a big believer in the Matronics Aeroelectric list. The 'patriarch' of the list is Bob Nuckolls, who has at least 4 decades of experience in the certified a/c world, and wrote 'the book' on homebuilt electrical systems. No homebuilt should be wired without it. :-) He sells printed copies, or you can download it for free from the Aeroelectric web site.

Protecting B-leads has been discussed quite a bit over there. Something that any circuit designer would say is that the circuit protection protects the *wire*; not any devices in the circuit. The alternator B-lead can be confusing, since the alternator is supplying power. BUT, the wire should be sized to handle anything that the alternator can throw at it. (Alternators are self-limiting; they can only deliver a slight amount more current than their rating.) So the alternator can never damage the wire. However, the battery *can* damage the wire, as Jeff discovered. So....B-lead protection needs to be on the *battery end* of the B-lead. Not at the battery itself, of course, unless the B-lead goes all the way to the battery terminal. But where ever the smaller sized B-lead is terminated, closest to the battery. Sizing the protection could vary a bit, depending on what type of device is used. Some fuses are quite fast acting, and need to be up-sized quite a bit to avoid nuisance trips, but a lot of the higher current 'current limiter' (hate that term) devices have quite long time constants and can be sized at the rating of the wire itself.

Jeff, congrats on getting it on the ground quick. If the relay hadn't burned open, the battery would have been depleted pretty quickly. Did your low voltage monitor light up?

Charlie



On 8/2/2018 10:44 AM, Andrew Martin andrew@martinag.com.au wrote:
My fuse is 100amp mounted close to the B post on an 80 amp alternator

Andrew




On Thu, Aug 2, 2018 at 11:39 PM, Jeff Whaley jwhaley@datacast.com <flyrotary@lancaironline.net> wrote:
Bobby, no I did not fuse the B lead.  What amperage would it be if installed?
Jeff

Jeff,

Do you have a fuse in the B lead?

Bobby

-----Original Message-----
From: Jeff Whaley
Sent: August-02-18 10:41 AM
To: Rotary motors in aircraft
Subject: Alternator Damaged - Internal Short

Last Thursday I decided to try my cooling on a hot day 32C (90F); orbiting the airport, the cooling wasn't too bad but while waiting for the temps to stabilize I smelled smoke so landed immediately.  Saw a bit of smoke exiting the oil cooler plenum so thought I was baking some fiberglass.
On the weekend I did a more thorough inspection and found the battery mains cable burned where attached to my alternator cut-out relay and the relay fried to the point that the input terminal was loose.  The connections stayed in place but open-circuited the relay - so the engine never skipped a beat and I was unaware there was an electrical problem at the time. Only reporting this now as it took me a while to get the alternator tested.
Jeff

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