Slip Ring Thermistor

[solocam92]

Has anyone connected a thermistor to a slip ring? I initially tried using a thermocouple but since there is a change in metals going through the slip ring unwanted emf voltages were generated which were dependent upon ambient air. My next thoughts were to try a thermistor or RTD and Wheatstone Bridge. If anyone has done this before and could lend some advice that would be great.

 

[Compositepro]

These rotary connectors are far superior to slip rings for low level signals.

http://www.mercotac.com/index.html

 

[Skogsgurra]

We used to have those in our tool-box. But we are not allowed to use them any more.

The reason is that they contain mercury (Hg), which is banned in most countries where we work.

The name MERCO-tac says something about its inner construction. I do not know of any metals other than mercury that is liquid at room temperature. If they have come up with something other than mercury, I think they should tell the world about it.


Slip-rings should work quite well with NTC thermistors. You can use 10 V DC and there are components that allow better than +/-1 C over quite a large temperature range. We usually use B and R25 to calculate temperature, but have also used linearization with a series-parallel combination with thermistor and resistors. Works quite well over 0 to 100 C, but not as well as the numerical calculation.

Gunnar Englund

http://www.gke.org

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Half full - Half empty? I don't mind. It's what in it that counts.

 

[solocam92]

Thanks for the advice guys. I actually am using a Mercotac mercury filled slip ring because of its low resistance.

 

[IRstuff]

As with thermocouples, one could use a reference thermistor going through the same slip ring to calibrate out the additional error sources.

TTFN
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