X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml@lancaironline.net Date: Thu, 22 Jan 2009 09:17:48 -0500 Message-ID: X-Original-Return-Path: Received: from [216.200.145.38] (HELO omta0105.mta.everyone.net) by logan.com (CommuniGate Pro SMTP 5.2.11) with ESMTP id 3436151 for lml@lancaironline.net; Tue, 20 Jan 2009 22:05:37 -0500 Received-SPF: none receiver=logan.com; client-ip=216.200.145.38; envelope-from=bknotts@buckeye-express.com Received: from sj1-dm101.mta.everyone.net (sj1-slb03-gw2 [172.16.1.96]) by omta0105.mta.everyone.net (Postfix) with ESMTP id 5C4207317DD for ; Tue, 20 Jan 2009 19:09:12 -0800 (PST) X-Eon-Dm: sj1-dm101 Received: by sj1-dm101.mta.everyone.net (EON-AUTHRELAY2 - 48f0e111) id sj1-dm101.49768c3c.ab4 for ; Tue, 20 Jan 2009 19:05:00 -0800 X-Eon-Sig: AQK8DXBJdpDcpx8GlwIAAAAB,dde4b0bc20ebe26cac83a8322fafe642 X-Original-Message-ID: <497690D7.1000405@buckeye-express.com> X-Original-Date: Tue, 20 Jan 2009 22:04:55 -0500 From: "F. Barry Knotts" Reply-To: bknotts884@earthlink.net User-Agent: Thunderbird 2.0.0.19 (Windows/20081209) MIME-Version: 1.0 X-Original-To: Lancair Mailing List Subject: Re: [LML] Alternator Load Dumping and Voltage Spike References: In-Reply-To: Content-Type: multipart/alternative; boundary="------------040007050107000901040406" This is a multi-part message in MIME format. --------------040007050107000901040406 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Jeffrey Liegner, MD wrote: > I recently experienced a sudden failure of my PS Engineering intercom > during the take off roll, Very interesting and timely post. I have been having a similar experience. My LIV-P has been eating avionics. In 100 hours I've lost the PS Engineering audio panel, AOA computer, encoding altimeter, one headset, and my electronic trim controller board (Precise Flight)...The loss of trim was particularly troublesome, it went out during decent and just before I needed to shoot an ILS...fortunately to a high ceiling. I have also discovered a nasty power surge that occurs only when I shut off the low boost pump and then only on some occasions. My first impression was that I might have a big back EMF surge. There's no obvious surge when I have the high boost on, though, but I've only attempted that on the ground at idle or slightly above. I have a couple TranZorb devices on their way from Digi-Key. I'm concerned that they may not be nearly beefy enough to withstand the surges that seem to be going through my avionics. And exactly where do I put them? Across the leads to the fuel pump? Any thoughts about how the chase down this intermittent gremlin? LIV-P, Conti TSIO-550, 24V 100 Amp alternator with full size battery, reserved and isolated backup 24V 100 Amp alternator and full size battery. Barry Knotts --------------040007050107000901040406 Content-Type: text/html; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit
Jeffrey Liegner, MD wrote:
Alternator Load Dumping and Voltage Spike
I recently experienced a sudden failure of my PS Engineering intercom during the take off roll,

Very interesting and timely post.  I have been having a similar experience.

My LIV-P has been eating avionics.  In 100 hours I've lost the PS Engineering audio panel, AOA computer, encoding altimeter, one headset, and my electronic trim controller board (Precise Flight)...The loss of trim was particularly troublesome, it went out during decent and just before I needed to shoot an ILS...fortunately to a high ceiling.

I have also discovered a nasty power surge that occurs only when I shut off the low boost pump and then only on some occasions.  My first impression was that I might have a big back EMF surge.  There's no obvious surge when I have the high boost on, though, but I've only attempted that on the ground at idle or slightly above.

I have a couple TranZorb devices on their way from Digi-Key.  I'm concerned that they may not be nearly beefy enough to withstand the surges that seem to be going through my avionics.  And exactly where do I put them?  Across the leads to the fuel pump?

Any thoughts about how the chase down this intermittent gremlin?

LIV-P, Conti TSIO-550, 24V 100 Amp alternator with full size battery, reserved and isolated backup 24V 100 Amp alternator and full size battery.

Barry Knotts


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