EGT installation

[Eric Elliott]

Hello,
Thermocouples are often grounded to case at tip for best thermal connection.
Ungrounded thermocouples (TC) are more expensive and prone to failure, plus
having slower response time. Most instrumentation is grounded at sensor end
or shielded with shield grounded at sensor end only. The instrument or meter
or indicator or control room end is usually not grounded. The meter circuit
often provides isolation from power supply ground. DC to DC isolated power
supply modules are $6 from Marlin Jones, 800.652.6733. If you use a 9 V
battery powered thermocouple meter no grounding or ground loop problem
happens.
Preferred mounting method is a pipe to tube fitting. Drill & tap for male
national pipe thread, screw in fitting. Drill thru fitting with nominal tube
size drill so that tube can go on thru fitting. Inset tubular TC just past
end of fitting & tighten fitting tube nut. This assumes TC is enclosed in a
tube of standard size diameter.
Bare TC may be mounted with hose or tube clamp but will indicate low
temperature.

Eric


-----Original Message-----
From: A. Bosch <abosch at sports.uct.ac.za>
To: diy_efi at efi332.eng.ohio-state.edu <diy_efi at efi332.eng.ohio-state.edu>
Date: Tuesday, March 31, 1998 10:53 AM
Subject: Re: EGT installation


>
>> Hi all
>>
>> Maybe a silly question, but how do you actually mount/ install an
>>EGT probe into the exhaust header: if the thermocouple contacts the
>> exhaust its going to make an unwanted electrical contact at that
>> point; so surely it must be insulated from the exhaust metal somehow?
>>
>>Any ideas?  Thanks.
>>
>> Andrew
>
>Dr A. N. Bosch
>Physiology Department/ Sports Science Institute
>University of Cape Town Medical School
>P. O. Box 115
>Newlands 7700
>South Africa