X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from fed1rmmtao04.cox.net ([68.230.241.35] verified) by logan.com (CommuniGate Pro SMTP 4.3c5) with ESMTP id 951062 for flyrotary@lancaironline.net; Fri, 20 May 2005 12:06:01 -0400 Received-SPF: none receiver=logan.com; client-ip=68.230.241.35; envelope-from=ALVentures@cox.net Received: from BigAl ([68.7.14.39]) by fed1rmmtao04.cox.net (InterMail vM.6.01.04.00 201-2131-118-20041027) with ESMTP id <20050520160510.VGKS23392.fed1rmmtao04.cox.net@BigAl> for ; Fri, 20 May 2005 12:05:10 -0400 From: "Al Gietzen" To: "'Rotary motors in aircraft'" Subject: Shielded wires Date: Fri, 20 May 2005 09:05:14 -0700 Message-ID: <000001c55d55$b51961b0$6400a8c0@BigAl> MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0001_01C55D1B.08BCFAB0" X-Priority: 3 (Normal) X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook, Build 10.0.6626 Importance: Normal In-Reply-To: X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.2180 This is a multi-part message in MIME format. ------=_NextPart_000_0001_01C55D1B.08BCFAB0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable Hi John, I have been tracking your progress on the EC2. One thing about using shielded cables. Both ends need to be grounded and do not use the shield as a conductor for any function. Data running in adjacent cables = can be corrupted by currents in cables next to them. If the shields = are not grounded at both ends you have created an antenna. Good luck. =20 Joe; =20 Best practice is to ground wire shield at only one end. Grounding both = ends results in multiple ground paths, and the potential for "ground loops"; slight differences in ground potential. I'm not sure about your concern about the antenna effect; whatever minute signals picked up simple go to ground. =20 Another point about the shielded wires to the EC2 or EM2 - it is = generally only an issue where there is significant distance between computer = module and program module (EC2) or display (EM2); as likely happens in canard = style aircraft. (I think mainly this concerns the EM2). I had some problems = with the EM2 which where solved by Tracy adding a capacitor (filter) in the display module, and by me getting the display wiring bundle a little = further away from the injector and ignition power leads. =20 The injector and ignition power leads are very "noisy", especially the ignition leads. This noise spreads through the entire power = distribution system as I have measured with an oscilloscope. Not necessarily an = issue, but can be quieted down by adding a filter (large capacitor between = power lead and ground), preferably near the coil or injector end of the lead. =20 FWIW, =20 Al ------=_NextPart_000_0001_01C55D1B.08BCFAB0 Content-Type: text/html; charset="us-ascii" Content-Transfer-Encoding: quoted-printable

Hi John,
        I have = been tracking your progress on the EC2.  One thing about using shielded cables.  Both ends need to be grounded and do not use the shield as = a conductor for any function.  Data running in adjacent cables can be corrupted by currents in cables next      to them.  If the shields are not grounded at both ends you have = created an antenna.  Good luck.

 

Joe;

 

Best practice is to ground wire = shield at only one end.  Grounding both ends results in multiple ground = paths, and the potential for “ground loops”; slight differences in = ground potential.  I’m not sure about your concern about the antenna = effect; whatever minute signals picked up simple go to ground.

 

Another point about the shielded = wires to the EC2 or EM2 – it is generally only an issue where there is = significant distance between computer module and program module (EC2) or display = (EM2); as likely happens in canard style aircraft.  (I think mainly this concerns = the EM2).  I had some problems with the EM2 which where solved by Tracy adding a = capacitor (filter) in the display module, and by me getting the display wiring = bundle a little further away from the injector and ignition power = leads.

 

The injector and ignition power = leads are very “noisy”, especially the ignition leads.  This = noise spreads through the entire power distribution system as I have measured = with an oscilloscope.  Not necessarily an issue, but can be quieted down by = adding a filter (large capacitor between power lead and ground), preferably = near the coil or injector end of the lead.

 

FWIW,

 

Al

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