X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml Date: Sat, 26 Aug 2006 15:17:28 -0400 Message-ID: X-Original-Return-Path: Received: from imo-d05.mx.aol.com ([205.188.157.37] verified) by logan.com (CommuniGate Pro SMTP 5.1c.3) with ESMTP id 1349871 for lml@lancaironline.net; Sat, 26 Aug 2006 12:27:17 -0400 Received-SPF: pass receiver=logan.com; client-ip=205.188.157.37; envelope-from=Sky2high@aol.com Received: from Sky2high@aol.com by imo-d05.mx.aol.com (mail_out_v38_r7.6.) id q.bb8.500dcac (32913) for ; Sat, 26 Aug 2006 12:26:31 -0400 (EDT) From: Sky2high@aol.com X-Original-Message-ID: X-Original-Date: Sat, 26 Aug 2006 12:26:31 EDT Subject: Re: [LML] Re: Dual bus architecture X-Original-To: lml@lancaironline.net MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="-----------------------------1156609591" X-Mailer: 9.0 Security Edition for Windows sub 5330 X-Spam-Flag: NO -------------------------------1156609591 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit In a message dated 8/26/2006 9:44:57 A.M. Central Standard Time, marv@lancaironline.net writes: Pardon the ignorance, but why are these diodes required? Robert, When there is a failure on either the left or right bus, the remaining good bus can drive the avionics bus and the essential bus without back feeding to the bad bus. Switches would greatly complicate things. The Perihelion Schottky power diode is excellent because of the low voltage drop at reasonable power draws. That is that the buses so connected will operate at a slightly lower voltage than the main buses. I use one to isolate my essential bus from the main bus when the essential bus must be switched directly to the battery. Also one is used to isolate the electronic ignition and backup battery from the main bus if the backup battery must be called into play (switched as sole power to the EI). This allows the backup battery to share the charging power from my single alternator during normal operation but be totally isolated if there is a problem. Scott Krueger AKA Grayhawk Lancair N92EX IO320 SB 89/96 Aurora, IL (KARR) Everything in moderation. -------------------------------1156609591 Content-Type: text/html; charset="US-ASCII" Content-Transfer-Encoding: quoted-printable
In a message dated 8/26/2006 9:44:57 A.M. Central Standard Time,=20 marv@lancaironline.net writes:
<= FONT=20 style=3D"BACKGROUND-COLOR: transparent" face=3DArial color=3D#000000 size= =3D2>Pardon=20 the ignorance, but why are these diodes required?
<= /DIV>
Robert,
 
When there is a failure on either the left or right bus, the remaining=20= good=20 bus can drive the avionics bus and the essential bus without back feeding to= the=20 bad bus.  Switches would greatly complicate things.
 
The Perihelion Schottky power diode is excellent because of the low vol= tage=20 drop at reasonable power draws. That is that the buses so connected wil= l=20 operate at a slightly lower voltage than the main buses. 
 
I use one to isolate my essential bus from the main bus when the essent= ial=20 bus must be switched directly to the battery.  Also one is used to=20 isolate the electronic ignition and backup battery from the main bus if= the=20 backup battery must be called into play (switched as sole power to the=20 EI).  This allows the backup battery to share the charging power from m= y=20 single alternator during normal operation but be totally isolated if there i= s a=20 problem.=20
 
Scott Krueger=20 AKA Grayhawk
Lancair N92EX IO320 SB 89/96
Aurora, IL=20 (KARR)

Everything in moderation.
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