[Milsurplus] RE2 and Bill Perry.

[Jim Whartenby]

Well said CharliePer Wikipedia, https://en.wikipedia.org/wiki/Thermocouple, if the thermocouple is a Type K, it has a sensitivity of 41 microvolts per degree C.  A Type E has the highest output at 61 microvolts per degree C.  For a meter movement to react to this feeble voltage, either the meter movement magnet itself is feeble or there is a high number of turns in the meter coil or both.  Then there is the problem of aging with the meter movement and thermocouple both being over 80 years old, it is no wonder that there is an issue.  
Being a temperature reacting device, there is also a time delay as everything reaches equilibrium.  I agree with Charlie, the scale is most likely relative and no two meters will agree on the absolute reading.  This ammeter is not a laboratory grade meter but it is being treated as such.  
F.W. Chesson calls out T.O. 08-5-57, not sure that there is any mention on how the BC-442 actually works.  Does anyone have a copy?Regards,Jim  
Logic: Method used to arrive at the wrong conclusion, with confidence.  Murphy 

    On Monday, June 16, 2025 at 10:28:44 AM CDT, Charlie L. <mjcal79 at gmail.com> wrote:   

 Bill used to not like email, he always wanted you to call him, but he finally got into the email stuff.  A lot of folks dropped their landline now, and use only cell, so let's hope that is the issue.  He does/did answer his email, but it has been a while since I needed anything from him.
My original question about the RE2 was due to mine being dead apparently, with no specs on the thermocouple, but Mark got some reading for me to compare too, thanks Mark.
The standard method to check a MA meter's internal resistance was to put a pot across it, feed voltage to it, and set the pot for half scale on the meter, then read the ohm value from the pot.  Normally,  a meter with a 6 ma movement will pin out if you put a Simpson 260 on it at RX1, but on the two RE2's I have, I get barely a wiggle.  The only reason I specified 6MA, is had one that had been tagged  '6MA Movement', so somebody must have checked it at one time.  The other note mentioned I did not realize, the meter is not called in amps, just in a relative scale, so without using another metere with an actual amp scale, no idea what the numbers mean.  It would also seem to get 6ma out of a thermocouple might be hard to do too, but don't know.  Guess one test is to just put the 'Remote/Local' switch to remote and put an low MA meter in the circuit to see if it deflects, eliminating the thermocouple as the culprit.
Charlie, W4MEC in NC
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