Sudden drop in thermocouple temperature?
Thread Content
Recently, the jacket temperature of one gas generation furnace has been abnormal. The measured voltage values were normal, but the temperature would often drop suddenly from around 180 degrees to around 70 degrees, with significant fluctuations. When the temperature sensor connector was removed and rewired on-site, the temperature became normal and the fluctuations decreased, but this situation lasted only a few days before the temperature dropped sharply again; removing the connector and rewiring it once more would prevent such drops for a few days more. We have replaced the temperature field connectors now, but this sudden drop in temperature still occurs frequently. Does anyone know what the problem is?
LZ, may I ask if there are any large-scale equipment nearby? Electromagnetic interference can also cause fluctuations in the readings of the instruments. Additionally, it’s important to check whether the cold junction of the thermocouples is properly compensated, whether the connections are secure, whether the compensation wires are identical, whether there is any water leakage in the environment where the instruments are installed, and whether there are any loose connections to ground elsewhere, among other things
1. The thermoelectric element is either broken or not. 2. Poor contact at the terminals. 3. Intermittent or short circuits in the measurement circuit, as well as grounding issues. 4. External interference, electromagnetic induction, etc. 5. Changes in the temperature of the cold end
This phenomenon is quite difficult to understand. What is the working environment of the thermocouple? Could it be local short circuits caused by moisture or water intrusion, or is there some interference present? The temperature should not change suddenly under normal conditions.
Everyone upstairs has said great things; let’s check them one by one. If it’s convenient, try switching to another one.
If the thermocouple is fine, check whether there are any issues with the connections, and whether the wiring box and terminals have become damp or anything of the sort
There is a problem with the thermocouple. It might be a phenomenon caused by a short circuit. Because normally it’s 180 degrees, but suddenly it becomes 70 degrees – 70 degrees being the temperature at the short circuit. When you made the connections, you actually separated the short circuit, but the thermocouple may have stuck together again after being heated for some time, resulting in a short circuit.