What trans. temp. sender?

[JSanchez]

I was wondering what trans. temp. sender I could use that has 2 wires so I can connect it to the pyro 2 position on my outlook monitor? Has anyone done this before? I'd really appreciate all feedback.

Thanks,

J. S.

 

[rbattelle]

Your basic issue here is RTD vs. Thermocouples.

An RTD is a "Resistance Temperature Device". It works on the basic principle that a change in temperature precipitates a change in resistance of a metal (usually brass).

A Thermocouple works on the principle that a small voltage is generated when two dissimilar metals (usually chromium and aluminum, I think) are welded together. A change in temperature along the wires produces a small voltage, which is directly (almost linearly) proportional to temperature.

Thermocouples have 2 wires, for obvious reasons.

RTD's need only 1 wire, since you're just measuring a resistance.

RTDs are generally slow to respond, and so they're good for applications where temperature change occurs slowly (like in transmissions, axles, and engine coolant).

Thermocouples are very fast responders, so they're used for EGT and other parameters that change rapidly.

Now, a thermocouple would work perfectly fine for measuring pretty much anything an RTD is used for - including transmission temperature.

So the question is, how do we get a thermocouple mounted in a spot where an RTD is normally supposed to go?

Simple! Buy yourself a thermocouple (probably K-type, but check with Edge to be certain that's what the Outlook is calibrated for), then make up a custom fitting using some pipe fittings to mount the thermocouple.

Piece of cake, believe me. Most RTD's for automotive applications seem to be 1/8-NPT, so I'll assume that's what you need to get. I'd buy a brass 1/8-NPT pipe plug, drill the end of it, insert the thermocouple (buy a tiny one), and epoxy it into the pipe plug. (Use a through-hole in the plug).

Or, if you're lazy, you could pick up one already made for you at Omega.
(Here's a link straight to the product you need).

Let us know how it goes!!

Ryan

 

[JSanchez]

Thanks for all the info! I'll try the thermocouple idea because I like the thought that it responds faster to changes in temp. I'll let you know how it goes.