Return-Path: Received: from imo-r15.mx.aol.com ([152.163.225.69]) by ns1.olsusa.com (Post.Office MTA v3.5.3 release 223 ID# 0-64832U3500L350S0V35) with ESMTP id com for ; Thu, 31 Aug 2000 02:52:23 -0400 Received: from RWolf99@aol.com by imo-r15.mx.aol.com (mail_out_v28.15.) id k.d3.95377cd (3977) for ; Thu, 31 Aug 2000 02:58:54 -0400 (EDT) From: RWolf99@aol.com Message-ID: Date: Thu, 31 Aug 2000 02:58:53 EDT Subject: Re: Thermocouple Connectors To: lancair.list@olsusa.com X-Mailing-List: lancair.list@olsusa.com Reply-To: lancair.list@olsusa.com Mime-Version: 1.0 <<<<<<<<<<<<<<<<--->>>>>>>>>>>>>>>> << Lancair Builders' Mail List >> <<<<<<<<<<<<<<<<--->>>>>>>>>>>>>>>> >> Geez! Try to omit one minor detail and the Lancair Mail List guys catch you every time! I actually though about including this nuance last night and said to myself "Naw, nobody's gonna call me on this one." More fool, me. Brent is absolutely correct. In principle, one could use any connector in a thermocouple line. If there were a transition from thermocouple wire to another metal at the connector (like from a chromel wire to a gold-plated pin) and a corresponding junction back to the original thermocouple material (like from the gold plated socket to a chromel wire) and both of these transitions were at the same temperature (almost certainly the case with a connector) then there would not be an erroneous reading. The potential generated in the transition from chromel to gold is balanced by an opposite potential in the transition from gold back to chromel, and this opposite potential is equal if both transitions are at the same temperature (which is quite likely since the pin is stuck into the socket). But using the thermocouple connector is good practice. Besides, ain't nobody gonna put 12 volts into a thermocouple connector thinking it's an intercom power cable or something. By the way, you MUST have the thermocouple wire go all the way to the electronic box (or more accurately, now that I know it's required, to the temperature-compensated thermocouple amplifier that is undoubtedly contained therein) OR ensure that the connector is at the same temperature as the thermocouple amplifier (which would be very hard to do in practice). If you insist on using a non-thermocouple connector (shame on you!) then don't run copper wires from the connector to the electronic box. Do what you will. This is a non-safety item. Me, I'd use the thermocouple connector. - Rob Wolf >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> LML website: http://www.olsusa.com/Users/Mkaye/maillist.html LML Builders' Bookstore: http://www.buildersbooks.com/lancair Please send your photos and drawings to marvkaye@olsusa.com. >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>