Thermisistor

WaldoDTD

So I am looking at using a thermisistor to monitor a wire's temperature that is submerged in either oil or antifreeze. I am wondering if I insulate the leads up to the sensor would that protect it from a short circuit and any voltage noise going through the wire in the heat sink fluid? If these are problems how would be the best way to sense the wire's temperature? Thank you-Waldo

erco

You definitely have to keep your wires insulated and isolated from any hot fluids. Sounds like a car/motorcycle application, subject to heat, thermal cycling, vibration, corrosion, etc. I wouldn't leave a delicate thermistor exposed in any environment like that. Consider installing it inside a drilled-out bolt which gets screwed into a tapped hole in your engine block. Bury just the epoxy thermistor head in a bit of aluminum-powder filled epoxy for good heat conduction, but use regular non-conducting epoxy to fill the bolt around the two wires. You can ground one lead against the bolt, then bring just one wire out through a threaded brass screw contact which is also held in with epoxy. JB Weld works great for moderate temps. (oil temps<250 F).

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·"If you build it, they will come."

RobotWorkshop

Depending on where you want to install it (since it sounds like a harsh environment) you may want to check out some of the current crop of automotive sensors. There are a huge variety of them to chose from and are already designed to keep on functioning in tough environments. If you pick a fairly standard part you will have an easy way to get replacements down the road....

parsko

www.autopartswarehouse.com/productsearch/gmc_jimmy_water_temperature_sensor~delphi~DETS10078.html?apwcid=P1135867996W43b3f85c7ab9e&apwkwd=GMC+Jimmy+Water%20Temperature%20Sensor+Delphi

One of those above might do for you.

-Parsko