Main types and application locations
Exhaust temperature sensor
Installed at the exhaust port of the air compressor main unit or the outlet of the oil-gas separator, it monitors the exhaust temperature of compressed air.
When the temperature exceeds the set threshold (usually 100-120℃, varying by model), it triggers high-temperature protection to prevent the lubricating oil from degrading and failing due to overheating, or to avoid the risk of fire in the oil tank caused by high temperature.
Oil temperature sensor
Installed near the oil tank or oil cooler, it detects the temperature of the lubricating oil.
An excessively high oil temperature can lead to a decrease in lubricating oil viscosity and a weakened lubrication effect; an excessively low temperature may affect the efficiency of oil-gas separation. The sensor monitors the data to assist the control system in adjusting the cooling system (such as fans, water-cooling valves).
Motor temperature sensor
Usually embedded in the motor windings or installed on the motor housing, it monitors the operating temperature of the motor.
To prevent the motor from overheating and burning out due to overload, phase loss, or poor heat dissipation, it is an important basis for motor overload protection.
Environmental temperature sensor
Installed in the air compressor room, it monitors the environmental temperature and assists in judging the cooling system's heat dissipation efficiency, avoiding the impact on the unit's operation due to excessively high environmental temperature.
Common working principles
Thermocouple type: Utilizes the thermoelectric effect of the temperature difference between two different metal conductors, converting temperature changes into electrical signals, suitable for high-temperature environments (such as exhaust temperature detection).
Thermoresistor type (e.g., PT100): Based on the characteristic that the resistance of a metal changes with temperature, it measures the resistance value to calculate the temperature, with high accuracy, often used for oil temperature and motor temperature detection.
Semiconductor type: Small in size and fast in response, suitable for monitoring in environments with ambient temperature or low temperatures, with relatively lower cost.
Common faults and troubleshooting
Sensor failure: Manifested as abnormal temperature display (such as always being at the maximum value, minimum value, or jumping), possibly caused by component aging, lead breakage, or loose wiring, requires checking the wiring or replacing the sensor.
Reading deviation: Inaccurate calibration or contamination of the sensor (such as oil contamination), requires cleaning the sensor surface or recalibration.
False high-temperature alarm: May be caused by improper installation of the sensor (such as being close to a heat source but not contacting the measured part), requires adjusting the installation position to ensure good contact.
Maintenance and replacement key points
Regularly check if the sensor terminal connections are loose or oxidized to ensure stable signal transmission.
Clean the oil stains and dust on the sensor surface to avoid affecting the measurement accuracy.
When replacing, select a model that matches the original factory specifications (such as PT100 requires confirming the graduation number, thermocouples need to match the material), ensuring the output signal is compatible with the control system.
After replacement, perform temperature calibration to verify the consistency between the displayed value and the actual temperature (can use an infrared thermometer for auxiliary verification).
Air compressor temperature sensors are the "thermometers" that ensure the safe operation of the equipment. Their performance directly affects the protection accuracy and operational stability of the unit. Regular maintenance and timely replacement of faulty sensors can effectively reduce the risk of equipment damage caused by overheating.
