X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml Date: Tue, 29 Aug 2006 15:27:52 -0400 Message-ID: X-Original-Return-Path: Received: from imo-m17.mx.aol.com ([64.12.138.207] verified) by logan.com (CommuniGate Pro SMTP 5.1c.3) with ESMTP id 1354339 for lml@lancaironline.net; Tue, 29 Aug 2006 09:36:55 -0400 Received-SPF: pass receiver=logan.com; client-ip=64.12.138.207; envelope-from=Sky2high@aol.com Received: from Sky2high@aol.com by imo-m17.mx.aol.com (mail_out_v38_r7.6.) id q.3ae.7768b6b (57365) for ; Tue, 29 Aug 2006 09:36:05 -0400 (EDT) From: Sky2high@aol.com X-Original-Message-ID: <3ae.7768b6b.32259cc4@aol.com> X-Original-Date: Tue, 29 Aug 2006 09:36:04 EDT Subject: Re: [LML] Re: Dual bus architecture X-Original-To: lml@lancaironline.net MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="-----------------------------1156858564" X-Mailer: 9.0 Security Edition for Windows sub 5330 X-Spam-Flag: NO -------------------------------1156858564 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit In a message dated 8/29/2006 12:00:33 A.M. Central Standard Time, marv@lancaironline.net writes: It seems the dual diode setup is a technique to protect the electronics when using a single alternator feeding an essential avionics bus from two separate busses. My panel is two completely separate systems (each alternator feeding a single battery and powering a single buss) that can be tied together with the bus-tie if one alternator craps out. In my scenario is it possible that these diodes would afford additional protection when the buss-tie is activated? Robert, No, yes, maybe. They provide essential protection. The Columbia's schematic is for a dual alternator, dual regulator and dual battery system. The power source buses, emanating from the alternator/regulator/battery combination, use switches to cross tie or transfer the load from one side to the other. After that there are multiple buses that perform different functions. In the Columbia for example, an avionics bus is wired to both sides of the power source thru power diodes so that if one of the power source sides fail catastrophi cally, the power from the other side cannot feed into the failed side. The diodes allow power, from whatever source, to reach the avionics bus continuously. The same is true for the essential bus. Apparently the PFD is set up for two independent power sources, probably isolated internally with power diodes. Think of the power diodes as check valves, only allowing power to flow in the direction of the arrow. Scott Krueger AKA Grayhawk Lancair N92EX IO320 SB 89/96 Aurora, IL (KARR) Everything in moderation. -------------------------------1156858564 Content-Type: text/html; charset="US-ASCII" Content-Transfer-Encoding: quoted-printable

In a message dated 8/29/2006 12:00:33 A.M. Central Standard Time,=20 marv@lancaironline.net writes:

<= FONT=20 style=3D"BACKGROUND-COLOR: transparent" face=3DArial color=3D#000000 size= =3D2>It seems=20 the dual diode setup is a technique to protect the electronics
w= hen=20 using a single alternator feeding an essential avionics bus from
= two=20 separate busses. My panel is two completely separate systems=20 (each
alternator feeding a single battery and powering a single=20 buss) that can
be tied together with the bus-tie if one alternat= or=20 craps out. In my
scenario is it possible that these diodes= =20 would afford additional
protection when the buss-tie is=20 activated?

Robert,

No, yes, maybe. They provide essential protection. The=20 Columbia's schematic is for a dual alternator, dual regulator and dual=20 battery system. The power source buses, emanating from the=20 alternator/regulator/battery combination, use switches to cross tie or trans= fer=20 the load from one side to the other. After that there are multiple bus= es=20 that perform different functions. In the Columbia for example, an avionics b= us=20 is wired to both sides of the power source thru power diodes so that if one=20= of=20 the power source sides fail catastrophically, the power from the other side=20 cannot feed into the failed side. The diodes allow power, from whateve= r=20 source, to reach the avionics bus continuously. The same is true for the=20 essential bus. Apparently the PFD is set up for two independent power=20 sources, probably isolated internally with power diodes.

Think of the power diodes as check valves, only allowing power to flow=20= in=20 the direction of the arrow.=20

Scott Krueger=20 AKA Grayhawk
Lancair N92EX IO320 SB 89/96
Aurora, IL=20 (KARR)

Everything in moderation.

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