热电偶常见故障（Thermocouple fault）.docVIP

热电偶常见故障（Thermocouple fault） Common faults of thermocouple.Txt Thermocouple fault treatment method Occurrence of failure: A thermoelectric potential is smaller than the actual value. Reason analysis: (1) short circuit. (2) short wiring between terminals in thermocouple junction box. (3) the compensating wire is shorted because of insulation burn out. (4) the compensating wire does not match the thermocouple. (5) compensation wire and thermoelectric dipole connection. (6) the insertion depth is not enough and the installation position is incorrect. (7) the temperature of thermocouple cold end is too high. Treatment method: (1) after inspection, if it is caused by moisture, it can be dried; if it is not well insulated, it should be replaced. (2) open the box, the wire brush clean. (3) re insulating or replacing the new compensating wire at the short circuit. (4) replace the compensating wires of the same type. (5) reconnect correctly. (6) change the installation position and depth of insertion. (7) the connecting wire of thermocouple is changed into compensating line, so that the cold end is moved away from the high temperature zone. The B thermoelectric power is greater than the actual temperature. Reason analysis: (1) the compensating wire does not match the thermocouple model. (2) insufficient depth of insertion or incorrect installation position. (3) thermoelectric metamorphism. (4) interference signal is entered. (5) the reference temperature of thermocouple is high. Treatment method: (1) replace the same type of compensating wire. (2) change the installation position or insert depth. (3) replacement of thermocouples. (4) check the sources of interference and eliminate them. (5) adjust the reference temperature or correct. C, measuring instruments indicating unstable, sometimes without, when high and low. Reason analysis: (1) the contact between the heating pole and the terminal is not good. (2) thermocouple has intermittent short circuit or intermittent grounding