Mailing List flyrotary@lancaironline.net Message #33414
From: Bill Bradburry <bbradburry@allvantage.com>
Subject: Thermocouple grounding
Date: Mon, 28 Aug 2006 13:15:39 -0400
To: Rotary motors in aircraft <flyrotary@lancaironline.net>
This question may be for Tracy since I am using his EM2, but I assume
that the answer would be the same with other monitors
I am using the 2nd Gen oil pan which has an oil temperature switch in
it.  I have removed the switch from the housing and plan to make a "J"
thermocouple and install it in the housing.  If I pot the thermocouple
such that it does not touch the sides of the housing, is this considered
to be ungrounded?  The opposite if it touches?  If I crimp a ring
connector on the end of the thermocouple and clamp it to say, the intake
manifold, is it a grounded thermocouple?
Which type is best...grounded or ungrounded?

Also, I am not clear on the instructions.  Looking at CHT1 for example,
the white wire goes to P1-9 and the red wire goes to P1-12.  An astrick
says to ground the red lead pin at the connector if an ungrounded sensor
is used...does this mean connect the red lead to both P1-12 AND one of
the ground pins listed, or connect it just to one of the P1 ground pins
listed?

Sound like grounded sensors are less complicated.  How would you make
certain that the sensor is grounded in the oil temp housing example I am
using above?

Thanks for the assistance.

Bill Bradburry

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