Fault phenomenon of platinum rhodium thermocouple

Fault phenomenon of platinum rhodium thermocouple

The main symptoms of the malfunction are: 1 The thermoelectric potential is smaller than the actual value; 2. The thermoelectric potential is greater than the actual value; 3. The indication of the measuring instrument is unstable, sometimes intermittent, sometimes high and sometimes low; 4. The thermocouple has a large potential error.

One There are several reasons for the malfunction of platinum rhodium thermocouples where the thermoelectric potential is smaller than the actual value:
(1) Short circuit.
(2) Short circuit between terminals in thermocouple junction box.
(3) The compensating wire is short circuited due to insulation burnout.
(4) The compensation wire does not match the thermocouple.
(5) Compensate for the polarity reversal between the wire and the thermoelectric dipole.
(6) Insufficient insertion depth and incorrect installation position.
(7) The temperature at the cold end of the thermocouple is too high.
Detailed troubleshooting method for faults where the thermoelectric potential is smaller than the actual value:
(1) If it is caused by moisture after inspection, it can be dried; If it is due to poor insulation of the ceramic tube, it should be replaced.
(2) Open the junction box and clean the wiring board.
(3) Re insulate the short circuit or replace it with a new compensating wire.
(4) Replace with the same type of compensating wire.
(5) Reconnect correctly.
(6) Change the installation position and insertion depth.
(7) Replace the connecting wire of the thermocouple with a compensating wire to move the cold end away from the high temperature zone.

Diphenylrhodium There are several reasons for the occurrence of thermocouple faults where the thermoelectric potential is greater than the actual value:
(1) The compensation wire does not match the thermocouple model.
(2) Insufficient insertion depth or incorrect installation position.
(3) Thermoelectric electrode deterioration.
(4) There is interference signal entering.
(5) The reference temperature of the thermocouple is too high.

Detailed troubleshooting methods for faults with thermoelectric potential greater than actual:
(1) Replace the compensating wire with the same model.
(2) Change the installation position or insertion depth.
(3) Replace the thermocouple.
(4) Check the interference source and eliminate it.
(5) Adjust the reference temperature or make corrections.

III There are several reasons for the unstable, intermittent, and fluctuating readings of measuring instruments in thermocouples:
(1) The thermoelectric electrode has poor contact at the terminal post.
(2) Thermocouples have intermittent short circuits or intermittent grounding phenomena.
(3) The thermoelectric electrode has been broken or appears to be broken but not broken.
(4) The thermocouple is not securely installed and is swinging.
(5) The compensating wire has grounding or intermittent short circuit phenomenon.

The measuring instrument indication is unstable, sometimes intermittent, and sometimes high and low. Detailed handling method:
(1) Reconnect it.
(2) Remove the thermoelectric electrode of the thermocouple from the protective tube, identify the fault point and eliminate it.
(3) Replace with a new electrode.
(4) Install firmly.
(5) Identify the fault point and eliminate it.

4, The reasons for the large potential error of platinum rhodium thermocouples are as follows:
(1) Thermoelectric electrode deterioration.
(2) The installation position and method of the thermocouple are improper.
(3) The surface area of the thermocouple protective sleeve has excessive scale.
(4) Measure circuit short circuits (thermocouples and compensating wires).
(5) The thermocouple circuit is disconnected.
(6) The terminal post is loose.

Detailed troubleshooting methods for large potential errors in platinum rhodium thermocouples:
(1) Replace the thermocouple.
(2) Change the installation location and installation method.
(3) Clean up.
(4) Replace the insulation at the short circuit location.
(5) Find the broken line and reconnect it.
(6) Tighten the terminal post