Principle of temperature controller:
The temperature controller is the electric switching equipment that controls the temperature of the air-conditioned room. The temperature range of the air conditioning room controlled by the temperature controller is generally 18℃- 28℃. The temperature controller commonly used in window air conditioning is based on the principle of pressure action to push the contact on and off. Its structure is composed of bellows, temperature envelope (test tube), eccentric, micro switch and so on composed of a sealed induction system and a transfer signal power system.
Control methods are generally divided into two kinds; One is controlled by the temperature change of the object to be cooled, mostly using vapor pressure temperature controller, the other is controlled by the temperature change of the object to be cooled, mostly using electronic temperature controller. Temperature controller is divided into:
Mechanical type is divided into: vapor pressure type thermostat, liquid expansion type thermostat, gas adsorption type thermostat, metal expansion type thermostat.
The vapor pressure temperature controller is divided into: aerated type, liquid - gas mixture type and liquid - filled type. The mechanical type of household air conditioning is mainly based on this kind of temperature controller.
Electronic type is divided into: resistance type temperature controller and thermocouple type temperature controller.
The function of the circuit system:
The function of air conditioner circuit system is to control the normal and multifunctional operation of air conditioning, and protect the normal operation of compressor and fan motor. The main components of the circuit system are: temperature controller, heat protector, main control switch, running capacitor, fan motor running capacitor and so on are fixed in the control box. The left picture shows the electrical circuit diagram of a single-cooled air conditioner. The function of the temperature controller is to control the start and stop of the compressor.
Working principle
Vapor pressure type
The action of the bellows acts on the spring, and the elasticity of the spring is controlled by a knob on the control panel. The capillaries are placed at the air inlet of the indoor air conditioner and respond to the temperature of the indoor circulation return air. When the room temperature rises to the set temperature, the temperature agent gas expansion in the capillary and bellows makes the bellows extend and overcome the spring's elastic force to connect the switch contacts. At this time, the compressor runs and the system is refrigerated. When the room temperature drops to the set temperature again, the temperature envelope gas shrinks, the bellows shrink and the spring act together, and the switch is placed in the disconnecting position. Cut off the motor circuit of the compressor. This repeated action, so as to achieve the purpose of controlling the room temperature.
Electronic temperature controller
Electronic temperature controller (resistance type) is the use of resistance temperature sensing method to measure, generally using gold wire, copper wire, tungsten wire and semiconductor (thermistor, etc.) for temperature resistance, these resistance has its best point. Most household air conditioning sensors are thermistor type.
The thermistor thermostat is based on the principle of the Wheatstone bridge, (left) is the Wheatstone bridge. Connected to the BD at both ends of the power supply E, according to Kirchhoff's law, when the bridge resistance R1×R4=R2×R3, A and C two points of the potential equal, no current flow between the output end A and C, thermistor impedance R1 size with the rise or fall of the surrounding temperature changes, so that the balance is damaged, AC output current. Therefore, the temperature control range and operating temperature can be easily changed by selecting the appropriate thermistor when constructing the thermostat
Metal expansion thermostat:
According to the principle of heat expansion and cold contraction of objects. Heat expansion and cold contraction are common objects, but different objects have different degrees of heat expansion and cold contraction. The two sides of the double gold sheet are conductors of different substances, which bend the double gold sheet at the changing temperature due to different degrees of expansion and contraction, and touch the set contact or switch, so that the set circuit (protection) begins to work.