Return-Path: Received: from edison.chisp.net ([207.174.31.1] verified) by logan.com (CommuniGate Pro SMTP 4.2.2) with ESMTP-TLS id 420542 for flyrotary@lancaironline.net; Sat, 18 Sep 2004 13:12:53 -0400 Received-SPF: none receiver=logan.com; client-ip=207.174.31.1; envelope-from=billdube@killacycle.com Received: from tigger.killacycle.com (64-48-158-6-den-01.cvx.algx.net [64.48.158.6]) by edison.chisp.net (8.12.8/8.12.8) with ESMTP id i8IHCJmd013701 for ; Sat, 18 Sep 2004 11:12:20 -0600 Message-Id: <4.3.1.0.20040918103034.020d0740@mail.chisp.net> X-Sender: billdube@mail.chisp.net X-Mailer: QUALCOMM Windows Eudora Version 4.3.1 Date: Sat, 18 Sep 2004 11:04:37 -0600 To: "Rotary motors in aircraft" From: "BillDube@killacycle.com" Subject: Mini switches (was: Engine start) In-Reply-To: Mime-Version: 1.0 Content-Type: text/html; charset="us-ascii" At 10:12 AM 9/18/2004, you wrote:

FWIW - I have had every mini switch in my plane(-6A) eventually fail by 1000 hrs. I now use these big honkin switches and have no more problems. I suspect that the switch that comes with the autopilot is quitting now, but it will be tough to debug or replace.

        Big, "Click Clack" style toggle switches seem to take more abuse than the sexy little mini toggles. If you have the room, or are switching a substantial load, big toggles are generally the better choice. Regardless, don't buy cheesy Radio Shack switches of any sort.

        Like nearly everything else, you can get low-quality mini switches and high-quality mini switches. The high-quality mini switches cost more than $6 each. I buy switches from Digikey <http://www.digikey.com> When selecting a switch, be sure that it is rated for DC. The environmentally-sealed switches are nice. :^)

        Also, what often kills a switch is the "kick back" from and inductive load like a relay or a motor. It is good practice to put a "snubber" across the motor or relay coil. The snubber consists of a diode and resistor in series (sometimes a capacitor is added.) Often folks just use the diode alone. You place a reverse-biased diode across a motor to catch the inductive kickback when you open the switch that supplies the power. This greatly reduces the arc across the switch when you open it.