Air conditioning temperature sensor is a kind of sensor which converts temperature into electricity by using the law of various physical properties of material changing with temperature. The main physical properties that change regularly are body. Temperature sensor is the core part of temperature measuring instrument, and there are many kinds. According to the measurement method, it can be divided into contact type and non-contact type. According to the characteristics of sensor materials and electronic components, it can be divided into thermal resistance and thermocouple.
Thermal resistance temperature sensor thermal resistance temperature sensor is divided into metal thermistor and semiconductor thermistor. The resistance of most metal thermistors increases with the increase of temperature, which is called positive temperature coefficient; The resistance of semiconductor thermistor generally decreases with the increase of temperature, which is called negative temperature coefficient. Because the resistance of conductor and semiconductor changes with temperature, the corresponding temperature can be measured by measuring their resistance.
How to judge the quality of air conditioning temperature sensor
Xiaobian specially organized an article to talk about how to judge the quality of air conditioning temperature sensor. When judging the performance of the air conditioning temperature sensor, the constant frequency air conditioning should be set to the operation state of forced cooling, and the variable frequency air conditioning should be set to the operation state of trial operation. If the air conditioner can operate and the working current is basically normal after this setting, it is generally considered that there is a problem with the temperature sensor. If the resistance value of the air conditioning temperature sensor becomes larger or the resistance value of the compressor temperature sensor becomes smaller, the output frequency of the inverter will be lower and the refrigeration effect will be affected. Of course, there are other ways to judge whether the sensor is good or not
Analog method to judge whether the sensor is in good condition
According to the temperature detected by various temperature sensors or artificial simulation temperature to analyze whether the change curve of temperature and resistance is normal, so as to judge whether the temperature sensor is bad. The rule is that the temperature is inversely proportional to the resistance.
Judge the sensor according to the input voltage of CPU
According to the input voltage of various temperature sensors into the single-chip microcomputer CPU, the current temperature is analyzed to judge whether the temperature sensor is bad or not. The rule is that temperature is directly proportional to voltage.
What is the resistance value of air conditioning temperature sensor
In the work of air-conditioning maintenance, many air-conditioning maintenance technicians only replace the temperature sensor according to the resistance value. In fact, there is a major misunderstanding here. In addition to the resistance value of air conditioning temperature sensor, there is also a key parameter: temperature coefficient b value. The value of temperature coefficient b refers to the change rate of the percentage of resistance increase with the temperature resistance value when the temperature increases by one degree. Air conditioning manufacturers choose the most is 3435, 3450, 3470, 3950, 3960 and so on. The same resistance value, the temperature coefficient b value is different, in different temperature conditions, the resistance value changes greatly. In the air conditioning maintenance, if the resistance value and temperature coefficient b value are selected incorrectly, the air conditioning unit may not operate normally or work abnormally in a certain temperature area. The loss of key protection will eventually lead to the damage of key components of the unit and cause great economic losses to users.
In the air conditioning maintenance work, when the air conditioning temperature sensor is damaged, how to detect the resistance value and b value of the original specifications of the air conditioning temperature sensor on site. It’s very important. Only by selecting the correct temperature sensor specifications and parameters, can the air conditioning unit return to normal operation. To avoid a variety of potential failures of air-conditioning unit due to the wrong selection of temperature sensor and the failure of stable operation.
When we repair the air conditioner, we often find various problems of the air conditioner. For example, the user thinks that the refrigeration of the air conditioning unit is normal and the heating is abnormal. Or often report some temperature related faults. In fact, most of these faults are related to the wrong selection of temperature sensor by the previous repairer. If the specification parameters of the original temperature sensor of the air conditioning unit manufacturer can be detected on site, we can replace the temperature sensor correctly. Avoid air conditioning problems.