1. The working principle of the high voltage switch.
When the car is in use, the system pressure will be too high when the radiator is blocked, the cooling fan does not rotate, or there is too much refrigerant. If not adjusted, excessive pressure can damage system components.
The high-pressure pipeline is equipped with a high-pressure switch, most of which are installed on the liquid storage dryer and connected in series with the electromagnetic clutch circuit of the compressor or the fan circuit of the condenser. When the system pressure is too high, the high-pressure switch responds, cuts off the clutch circuit or connects the high-speed gear circuit of the cooling fan, so as to prevent the pressure from continuously rising and the system from being damaged.
2. Working principle of low voltage switch.
When the refrigerant in the refrigeration system is insufficient or leaks, the frozen lubricating oil may also leak correspondingly, resulting in poor lubrication of the air conditioning system. If the compressor runs without oil, it can seriously damage it.
The low-pressure switch is usually installed directly in the high-pressure pipeline with threaded joints and connected in series in the electromagnetic clutch circuit. Its structure is similar to a normally open high voltage switch. When the refrigerant pressure is normal, the movable contact is connected to the electromagnetic clutch circuit of the compressor. When the pressure of the refrigerant discharged from the compressor is too low, turn off the low-pressure switch, cut off the electromagnetic clutch circuit, and stop the compressor to avoid damage to the compressor.
In addition, when the ambient temperature is too low, the temperature and pressure of the refrigerant will decrease accordingly. For example, in an air-conditioning system using R12 refrigerant, when the ambient temperature is lower than 10°C, the refrigerant pressure is 0.423MPa, at this time the low-pressure switch is closed, and the compressor stops rotating, which will reduce power consumption and achieve energy saving.
3. Working principle of dual pressure switch.
The new air adjustable refrigeration system combines the high and low pressure switches into one to form a double pressure switch, which is installed on the liquid storage dryer, thereby reducing the number of pressure switches and interfaces, thereby reducing the possibility of refrigerant leakage.
4. Working principle of triple pressure switch.
The triple pressure switch is composed of a double pressure switch (high pressure switch, low pressure switch) and a medium pressure switch, and the structure is more compact. Triple pressure switches are installed in high pressure piping. When the pressure is too high or too low, the dual pressure switch adjusts the compressor to stop rotating; when the refrigerant pressure reaches a certain intermediate value, the medium pressure switch adjusts to open the condenser fan circuit.
