X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml@lancaironline.net Date: Wed, 26 Oct 2011 09:56:41 -0400 Message-ID: X-Original-Return-Path: Received: from nm1.access.bullet.mail.mud.yahoo.com ([66.94.237.202] verified) by logan.com (CommuniGate Pro SMTP 5.4.2) with SMTP id 5173173 for lml@lancaironline.net; Wed, 26 Oct 2011 06:31:08 -0400 Received-SPF: neutral receiver=logan.com; client-ip=66.94.237.202; envelope-from=browncc1@verizon.net Received: from [66.94.237.194] by nm1.access.bullet.mail.mud.yahoo.com with NNFMP; 26 Oct 2011 10:30:33 -0000 Received: from [66.94.237.107] by tm5.access.bullet.mail.mud.yahoo.com with NNFMP; 26 Oct 2011 10:30:33 -0000 Received: from [127.0.0.1] by omp1012.access.mail.mud.yahoo.com with NNFMP; 26 Oct 2011 10:30:33 -0000 X-Yahoo-Newman-Id: 848476.27355.bm@omp1012.access.mail.mud.yahoo.com Received: (qmail 950 invoked from network); 26 Oct 2011 10:30:33 -0000 X-Yahoo-Newman-Property: ymail-3 X-YMail-OSG: 4dN6OP0VM1mJkrPcG18n4nH_hwhZYmoFv7JEODQ5dZFQN.J CTnu5S_iYNvokcdYtkI0T9Q6J3V4RucJIO5j6QEUEACYTeVNK.sqGkleEvVU AxL3PIWVCZPdBBrZekk5XRZx1EBzkS84DSMRHXV8Ose4FK.HTctxiKKVKMo4 X2fBYHK6J5Q7aM22nNFW6WNp8A.XNP.hiGWsP54.c8V0Cv8D1i3YAv4xo3fY n98Yw.lNAzr5zZI_VBkrJZl2.5yuZ_zIvMWH9iMLWKEolURweAJn5gW6kMgO um2WgdFqzdqt_zup2Vwurg3UIWFqXMiPH728fRHmqa4xt4jJsDGQdmkYbivs sf8qvhfrklrUkgNaRj323oJOZHpRNFtbgR.9LM97eA0f6yrAx3CuDTIXuLOk p.MBvdS3Kgw2l3adRobb2R8IbmJwp X-Yahoo-SMTP: F49l9g6swBC0R9n8vJIbm7Tf3P8Xlmia8rHIwTlO__Ml Received: from chass-imac-2.home (browncc1@72.64.81.165 with plain) by smtp104.vzn.mail.bf1.yahoo.com with SMTP; 26 Oct 2011 03:30:32 -0700 PDT From: Charley Brown Mime-Version: 1.0 (Apple Message framework v1084) Content-Type: multipart/alternative; boundary=Apple-Mail-1--132067743 Subject: Re: [LML] Re: Problem with Fluctuating Amperage X-Original-Date: Wed, 26 Oct 2011 05:30:32 -0500 In-Reply-To: X-Original-To: "Lancair Mailing List" References: X-Original-Message-Id: <6E92865F-CBD3-4C6B-9059-7FB942406C19@verizon.net> X-Mailer: Apple Mail (2.1084) --Apple-Mail-1--132067743 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset=us-ascii 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--132067743 Content-Transfer-Encoding: quoted-printable Content-Type: text/html; charset=us-ascii
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.  

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.
 
Interesting = problem!
 
Dennis
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