Date: Sun, 28 Dec 2003 17:16:49 -0600
Reply-To: Larry Alofs <lalofs@RCN.COM>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Larry Alofs <lalofs@RCN.COM>
Subject: Re: What makes a pyrometer's cable so special?
Content-Type: text/plain; charset=us-ascii; format=flowed
If this is a thermocouple type of pyrometer, the type of wire can be
important. The thermocouple probe itself is a junction where two
different metals meet, typically just melted together in a small bead.
It produces a VERY small voltage roughly proportional to temperature.
For the common K type this is on the order of 6 mV (0.006 V) at 300
degrees F, if the other junctions in the circuit are at 32 F. The other
junctions of dissimilar metals in the circuit produce "contact
potentials" of their own which can influence the voltage seen by the
meter at the other end.
Take care,
Larry A.
David Marshall wrote:
> I just bought a VDO Pyrometer for a customers 1.9TD installation. VDO
> stressed to me that the cable can not be lengthened and if you need a longer
> cable than what comes with the kit I must order one that length.
>
> So, I ordered the gauge and a 14' cable that goes between the sensor on the
> exhaust manifold and the gauge.
>
> The cable that came with the gauge and the additional 14' long cable is two
> conductor, looks like aluminium 16 ga wire for each conductor. There is
> nothing [to me] that appears to be 'special' about this cable other than the
> freaking price that I paid for it. There is no shielding and the plastic
> covering that covers the two wires seems to be a little extra tough.
>
> Can someone enlighten me about what I am missing here!
>
> Also, on a semi-related note, how hot is too hot for a Turbo Diesel motor?
>
> Thanks in advance!
>
> David Marshall
>
> Fast Forward Automotive Inc.
> 4356 Quesnel-Hixon Road
> Quesnel BC Canada V2J 6Z3
>
> http://www.fastforward.ca mailto:sales@fastforward.ca
> Phone: (250) 992 7775 FAX: (250) 992 1160
>
> - Vanagon Accessories and Engine Conversions
> - Vanagon, Transporter and Iltis Sales and Importation
> - European Lighting for most Volkswagen models
>
>
> Due to the large volume of email we receive, PLEASE include previous
> emails when responding. This will allow us to read the complete dialogue
> in one message and will result in quicker and more accurate responses.
>
> David Marshall
>
> Fast Forward Automotive Inc.
> 4356 Quesnel-Hixon Road
> Quesnel BC Canada V2J 6Z3
>
> http://www.fastforward.ca mailto:sales@fastforward.ca
> Phone: (250) 992 7775 FAX: (250) 992 1160
>
> - Vanagon Accessories and Engine Conversions
> - Vanagon, Transporter and Iltis Sales and Importation
> - European Lighting for most Volkswagen models
>
>
> Due to the large volume of email we receive, PLEASE include previous
> emails when responding. This will allow us to read the complete dialogue
> in one message and will result in quicker and more accurate responses.
>
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