X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml@lancaironline.net Date: Fri, 28 Oct 2011 08:04:09 -0400 Message-ID: X-Original-Return-Path: Received: from nm25.access.bullet.mail.sp2.yahoo.com ([98.139.44.152] verified) by logan.com (CommuniGate Pro SMTP 5.4.2) with SMTP id 5175838 for lml@lancaironline.net; Fri, 28 Oct 2011 06:51:10 -0400 Received-SPF: neutral receiver=logan.com; client-ip=98.139.44.152; envelope-from=browncc1@verizon.net Received: from [98.139.44.103] by nm25.access.bullet.mail.sp2.yahoo.com with NNFMP; 28 Oct 2011 10:50:34 -0000 Received: from [98.139.44.81] by tm8.access.bullet.mail.sp2.yahoo.com with NNFMP; 28 Oct 2011 10:50:34 -0000 Received: from [127.0.0.1] by omp1018.access.mail.sp2.yahoo.com with NNFMP; 28 Oct 2011 10:50:34 -0000 X-Yahoo-Newman-Id: 900135.44955.bm@omp1018.access.mail.sp2.yahoo.com Received: (qmail 96366 invoked from network); 28 Oct 2011 10:50:34 -0000 X-Yahoo-Newman-Property: ymail-3 X-YMail-OSG: KTtdEm4VM1nMgcn_RryRR1YRySZ_j8jb7_KLhLBRzaUYoCH rohtlRKhXDPedfWY79pW1Q6C5K0SXE2j3KuiLoqSAZ_6I_IdZAqXJk2iHQBV dZxV5n3oUn7AJD0LXaVc863Vt6ejT.hvS6KKUOI2cmKirh17QV.QahVQAkRR FO.13clJk5HI_HruFoJ7CNJDhIFagZIfxni5.YFE.QAnYiq6OPooFGkq6FDE do0q_wL3Iiawm1u4y3AQqoWP8cZ34cWcJKpEejRShNIW7VToE5ahIISZ_mC. UuVQiWbEGgTfkOiT8_dDrUKaXX9B4kkp0YYlfuScZhuvcyZiHvciFx9ZXmKn iM5eMiM8SuXbIrm2d1x3dttHk.OFpT_M9ApNVumSfbfWDoeu15dc7pMEnhEJ a3I0vSOv2wtebVLlgEqunUYfKW9Cv X-Yahoo-SMTP: F49l9g6swBC0R9n8vJIbm7Tf3P8Xlmia8rHIwTlO__Ml Received: from chass-imac-2.home (browncc1@72.64.81.165 with plain) by smtp104.vzn.mail.ne1.yahoo.com with SMTP; 28 Oct 2011 03:50:33 -0700 PDT From: Charley Brown Mime-Version: 1.0 (Apple Message framework v1084) Content-Type: multipart/alternative; boundary=Apple-Mail-1-41932977 Subject: Re: [LML] Re: Problem with Fluctuating Amperage X-Original-Date: Fri, 28 Oct 2011 05:50:32 -0500 In-Reply-To: X-Original-To: "Lancair Mailing List" References: X-Original-Message-Id: <7CE7E0EF-C471-47AD-BA0A-CCA93A50B240@verizon.net> X-Mailer: Apple Mail (2.1084) --Apple-Mail-1-41932977 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset=us-ascii My last comment -- while out running yesterday the same thought occurred = to me as Colyn -- is it possible the whole thing's in the EIS itself? = Voltage cannot stay steady when amperage is running all over the place = -- so what if the charging system is just fine, and you have a periodic = issue in the EIS itself (or one of its connectins) that's causing bad = indications? Again, the periodicity of it suggests to me that heat = might be a factor, but that's just a guess. =20 As Mark Sletten suggested, just turning off the alternator briefly = during one of these episodes should tell you a whole lot about whether = it (and the regulator) are a factor. On Oct 27, 2011, at 8:36 AM, Colyn Case wrote: David, I had a problem with my GRT EIS that shares with your situation the = possibility that something bad happening on one channel of the EIS is = affecting some other channels on the EIS. In my case, one of my spade = connectors in my EIS harness poked through to ground with the result = that my tach went to zero. The solution in my case was to disassemble = the entire EIS sensor wire bundle and put it back together with special = care that nothing could ever poke through to anything else. If it were my airplane I think I would first wire up a temporary = ammeter/shunt and verify that your electrical system is okay. Then I would start disconnecting things on the EIS sensor bundle until I = found the culprit. Colyn On Oct 26, 2011, at 9:56 AM, Charley Brown wrote: Yeah, that's what I'm thinking. Steady voltage and wildly fluctuating = amps in a simple system like that just cannot both be true. = Possibilities: 1. Ammeter is not correctly calibrated, and the actual swings are a lot = smaller? But actually, the 15 amp value seems reasonable in a 12V = system; my 28V system pulls about 8-9A when the big loads are off (pitot = heat, landing lights). 2. The fact this effect cycles regularly, and doesnt occur for a while = in the first place, suggests a heat-related problem -- regulator heating = up, shutting off, cooling down, starts to work again, heats up, shuts = off, cools down...? But like the other guys said -- check the wires first. =20 Thoughts worth what you paid for them. CB On Oct 26, 2011, at 5:21 AM, Dennis Johnson wrote: If the voltage is steady at 13.8 while the amperage is fluctuating from = plus 15 amps to minus 50 amps, then either the voltmeter is broken or = the amperage reading is incorrect. My guess is the amperage reading is = wrong. Is there some kind of electromagnetic interference that is = causing the amp reading and the fuel gauges to go haywire at the same = time? Is the hydraulic pump cycling every five minutes and doing this? = I don't think hydraulic pumps are common antagonists, but I can't think = of anything else that might cycle every five minutes. It's always a = good idea to check grounds, but my guess is EMI. =20 Interesting problem! =20 Dennis ----- Original Message ----- From: Taylor, David To: lml@lancaironline.net Sent: Tuesday, October 25, 2011 6:00 PM Subject: [LML] Re: Problem with Fluctuating Amperage Voltage reads steady at 13.8 volts. Amp drop is on the EIS unit, so the = EFIS unit is not the cause. Good idea on downloading data. =20 Dave T. =20 From: Lancair Mailing List [mailto:lml@lancaironline.net] On Behalf Of = Dennis Johnson Sent: 10-25-11-Tue 14:01 To: lml@lancaironline.net Subject: [LML] Re: Problem with Fluctuating Amperage =20 Hi David, =20 What is the voltage reading during this time? Does the Grand Rapids = EFIS Sport record data that you can download and study after a flight?=20= =20 Dennis Legacy 450 hours ----- Original Message ----- From: Taylor, David To: lml@lancaironline.net Sent: Tuesday, October 25, 2011 4:50 AM Subject: [LML] Problem with Fluctuating Amperage =20 Any ideas about what would cause my amperage to start fluctuating wildly = about 5 minutes into a flight?=20 It starts out fine after takeoff at 15 amps and then goes to -50 amps = for 30 seconds, and then gyrates between 5 amps and -50 amps for a = minute and then goes back to normal. It repeats this sequence every 5 = minutes.=20 My fuel gages also go down to zero during this episode and then back to = normal. Is my B&C LR3C Linear Regulator going bad?=20 (I'm getting these readings from my Grand Rapids EIS engine monitor. = It's hooked up to a Grand Rapids EFIS Sport.) Thanks for the help! David T. Legacy RG =20 --Apple-Mail-1-41932977 Content-Transfer-Encoding: quoted-printable Content-Type: text/html; charset=us-ascii
David,

I had = a problem with my GRT EIS that shares with your situation the = possibility that something bad happening on one channel of the EIS is = affecting some other channels on the EIS.    In my case, one = of my spade connectors in my EIS harness poked through to ground with = the result that my tach went to zero.   The solution in my case was = to disassemble the entire EIS sensor wire bundle and put it back = together with special care that nothing could ever poke through to = anything else.

If it were my airplane I think I = would first wire up a temporary ammeter/shunt and verify that your = electrical system is okay.
Then I would start disconnecting = things on the EIS sensor bundle until I found the = culprit.

Colyn

On Oct = 26, 2011, at 9:56 AM, Charley Brown wrote:

If = the voltage is steady at 13.8 while the amperage is fluctuating from = plus 15 amps to minus 50 amps, then either the voltmeter is broken or = the amperage reading is incorrect.  My guess is the amperage = reading is wrong.  Is there some kind of electromagnetic = interference that is causing the amp reading and the fuel gauges to go = haywire at the same time?  Is the hydraulic pump cycling every five = minutes and doing this?  I don't think hydraulic pumps are common = antagonists, but I can't think of anything else that might cycle every = five minutes.  It's always a good idea to check grounds, but my = guess is EMI.
 
Interesting = problem!
 
Dennis
----- Original Message -----