Measuring voltage in a high temperature environment

[VLg]

Hi all,

Is there any customized probes that can be used with the NI-DMMs when measuring voltages (say, across a voltage source) in a high temperature environment? The temperature is in the range of 1300 to 1500 degrees C, in a test chamber. If not, is there any other alternatives which can be used? In addition, can we use thermocouples to measure the voltage?

Any help will be greatly appreciated 🙂

Thanks,

Victor L

[Neal M]

Hello Victor,

NI does not have any probes that can be used in the temperature range you are talking about.  The inputs of NI DMMs are standard female banana plugs, so if you can find a 3rd party cable that can be used in those temperatures with a male banana plug, it should work with the DMM.

I am unsure what you mean by using thermocouples to measure voltage.  It is most definitely possible to use thermocouples with a DMM to measure temperature, if that is what you are trying to do. 

I hope this helps, post back if you have any more questions.

[VLg]

Hi Neal,

Thanks for your reply 🙂

The application I am asking about is voltage measurements under very high temperatures. At these temperatures banana plugs would not work, so I was trying to ask if there is any alternative setups (3rd party or NI) that can be used.

When I meant "using thermocouples to measure voltage", I meant that because the metals/alloys used in a thermocouple can withstand high temperatures, perhaps we can utilize them to be the "leads" for the voltage measurement? E.g. if a type B thermocouple has 2 leads, platinum alloy A and platinum alloy B, can we simply use alloy A to fabricate the leads for our voltage measurement? The other end of the leads will lead to the DMM.

Victor

[Neal M]

Victor,

I think that should work since any voltage created by dissimilar metals in one lead should be offset by the other lead if its the same metal, so essentially all you are doing is extending the leads with wire... The only thing I can think of is if there is any change in resistance of the thermocouple wire with temperature, noise, or things of that nature.  You run into that kind of thing with any system though, especially with such high temperatures. It also might be cheaper if you just bought the wire separately instead of two thermocouples (especially if you could find a cheaper material that could withstand those temperatures).

[nitad54448]

Hi
i stumbeld upon your question. I am measuring voltage and temperatures around 1000 degrees C. I am using Pt/PtRh thermocuples for the temperatures and one leg of the thermcouple -the platinum one- as a voltage probe. You will need a switch (I am using a Keithley 7000 and 7055/7056 scanner cards). making contacts is a little tricky, use platinum epoxy. If you have access to scientific litterature I can send you a reference (some guys are using Rh wires for electric contacts)
regards
regards