Fault analysis and handling methods of thermistor temperature measuring instruments
Common faults of industrial thermoresistors are open circuits and short circuits. Generally, open circuits are more common due to the fine wire of the thermoresistor. Open circuits and short circuits are easy to identify; using a multimeter set to the "×1Ω" range, if the measured resistance is less than R0, there may be a short circuit; if the multimeter indicates infinity, it can be determined that the resistance element has an open circuit. Short circuits in the resistance element are generally easier to handle, as long as the length and thickness of the resistance wire are not affected, one can locate the short circuit and dry it out to enhance insulation. Repairing an open circuit in the resistance element usually requires changing the length of the resistance wire, which affects the resistance value, so it is better to replace it with a new resistance element. If welding is used for repair, it must be verified as qualified before it can be used.
Release time:
2022-04-07
Source:
Common faults of industrial thermistors are open circuit and short circuit. Generally, open circuits are more common due to the thin thermistor wire. Open circuits and short circuits are easy to identify; you can use a multimeter set to the "×1Ω" range. If the measured resistance is less than R0, there may be a short circuit; if the multimeter indicates infinity, it can be determined that the resistance body has an open circuit. Short circuits in the resistance body are generally easier to handle, as long as the length and thickness of the resistance wire are not affected. Find the short circuit point, dry it, and strengthen the insulation. Repairing an open circuit in the resistance body must change the length of the resistance wire, which affects the resistance value. Therefore, it is better to replace it with a new resistance body. If welding is used for repair, it must be verified as qualified before use.
Common faults and handling methods of thermistor thermometers during operation:
1. Fault phenomenon: The indicated value of the display instrument is lower than the actual value or the indication is unstable.
Possible reasons: There are metal shavings or dust in the protective tube, dirt between the terminals, and short circuits in the thermistor (such as water accumulation).
Handling method: Remove metal shavings, clean dust, water droplets, etc., find the short circuit point, and strengthen insulation.
2. Fault phenomenon: The display instrument indicates infinity.
Possible reasons: The industrial thermistor or lead wire is open circuit, and the terminal is loose.
Handling method: Remove metal shavings, clean dust, water droplets, etc., find the short circuit point, and strengthen insulation.
3. Fault phenomenon: The display instrument indicates a negative value.
Possible reasons: There is a wiring error between the display instrument and the thermistor, or the thermistor has a short circuit.
Handling method: Correct the wiring or find the short circuit point and strengthen insulation.
4. Fault phenomenon: The relationship between resistance value and temperature has changed.
Possible reasons: The thermistor wire material has corroded and deteriorated.
Handling method: Replace the resistance body (thermistor).
Key words:
Thermistor, thermistor faults, thermistor temperature measuring instrument, fault resolution
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