Return-Path: Received: from relay03.roc.ny.frontiernet.net ([66.133.131.36] verified) by logan.com (CommuniGate Pro SMTP 4.1.5) with ESMTP id 2642907 for flyrotary@lancaironline.net; Sun, 19 Oct 2003 20:32:08 -0400 Received: (qmail 3264 invoked from network); 20 Oct 2003 00:32:04 -0000 Received: from unknown (HELO frontiernet.net) ([170.215.97.8]) (envelope-sender ) by relay03.roc.ny.frontiernet.net (FrontierMTA 2.3.6) with SMTP for ; 20 Oct 2003 00:32:04 -0000 Message-ID: <3F932D35.D176F298@frontiernet.net> Date: Sun, 19 Oct 2003 19:32:53 -0500 From: Jim Sower X-Mailer: Mozilla 4.77 [en] (Win98; U) X-Accept-Language: en MIME-Version: 1.0 To: Rotary motors in aircraft , aeroelectric-list@matronics.com, reflector@tvbf.org Subject: Alternator Terminals ... References: Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Question for all you EEs out there. I'm putting a new alternator on my Velocity. This one will be internally regulated (and have the appropriate "crowbar" OV protection. The unit I am installing has two terminals arranged in a "T". One is "field" and the other is "Indicator" (idiot light). I am blessed that the builder didn't have a 20- or 22- ga wire to string from the "Alt" (split Alt-Master) switch, so he used both conductors of 2-wire shielded 24 ga for the 12 ft run from the switch to the regulator. Anyway, I am betting that one will be enough to excite the regulator and I can use the other for an idiot light. Thing is, I have to determine which is which and how the "I" lead works (is it hot or grounded when there is no output). I aim to wire things up with jumpers and spin the alternator by hand, so to get the charging voltage at B+ I will need a resistor between B+ and the line back to the battery. That done, I can connect stuff up and see if, when all ready to go, the "I" lead is hot or grounded, and if it goes cold or breaks ground connection when I spin up the unit. My questions are: Will this work (will I be able to easily twirl the pulley and get charging voltage if I put the proper resistor in the circuit (so it doesn't have to generate much current in order to build up charging voltage)? What would be an appropriate resistance (and size) of the resistor I am placing in the circuit? I know I could have all this done at an alternator rebuild shop, but there's none convenient to me Hope this will work. Makes sense to me at this point .... Jim S.