1. High voltage protection:

High pressure protection is to detect whether the refrigerant pressure in the system is normal. When the pressure exceeds the allowable range, the pressure switch will activate and transmit an abnormal signal to the high pressure controller. After processing, the refrigeration system will stop working and display the fault.

2. Low voltage protection:

Low pressure protection detects the return air pressure in the system, which prevents damage to the compressor due to low system pressure or lack of refrigerant operation.

3. Oil pressure protection:

A device that prevents bearings or other internal components of the compressor from being damaged due to low lubricating oil pressure. If the oil volume of the compressor decreases or the oil is cut off, it will cause serious damage to the high-speed compressor. The oil pressure protection device is an important component to ensure the safe operation of the compressor.

4. Anti freezing protection:

If the evaporator is too dirty or frosting is too severe, the cold air cannot fully exchange heat with the outside hot air, causing the internal unit to freeze. Indoor antifreeze protection is designed to stop the compressor before the internal unit freezes, providing protection for the compressor.

5. Current protection:

When a short circuit occurs in a power line, one of the important characteristics is that the current in the line increases sharply. This requires the setting of a corresponding protection device called overcurrent protection, which responds to the increase in current when the current flows through a predetermined value.

6. Overheating protection:

A well-designed motor that operates under specified conditions will not have an internal temperature exceeding the allowable value. However, when the motor operates at high or low voltage, or in a high-temperature environment, the internal temperature of the motor will exceed the allowable value. During frequent starting, the temperature may become too high due to excessive starting current.

7. Phase sequence protection:

Phase sequence protection is a protective relay that can automatically identify the phase sequence, avoiding accidents or equipment damage caused by reversing the power supply phase sequence (three live wires connected in reverse) to the motor.

For example, the structures of scroll compressors and piston compressors are different. Due to the fact that the inverter of the three-phase power supply can cause the compressor to invert, it cannot be reversed. Therefore, it is necessary to install a reverse phase protector to prevent the reverse rotation of the chiller unit. When installing a reverse phase protector, the compressor can operate in the positive phase. When opposite phases occur, it is necessary to change the two lines of the power supply to positive phase.

8. Phase imbalance protection:

Unbalanced voltage between phases will cause three-phase unbalanced current, resulting in greater temperature rise - set overload relay. In the maximum phase of current, the proportion of temperature rise increase is about twice the square of the voltage imbalance ratio. as3%The voltage imbalance will result in approximately18%The temperature rise.

9. Exhaust temperature protection:

Excessive exhaust temperature can cause refrigerant decomposition, aging of insulation materials, carbonization of lubricating oil, damage to air valves, and blockage of capillary tubes and dry filters. The main protection method is to use a temperature controller to sense the exhaust temperature. The temperature controller should be placed near the exhaust port. When the exhaust temperature is too high, the temperature controller will activate and cut off the circuit.

10. Chassis temperature protection:

The temperature of the casing will affect the lifespan of the compressor. The high temperature of the casing may be caused by insufficient heat transfer capacity of the condenser, so it is necessary to check the scenery or water volume of the condenser, and whether the water temperature is appropriate. If air or other non condensable gases are mixed into the refrigeration system, the condensation pressure will rise and the casing will overheat; If the suction temperature is too high, the casing is prone to overheating. In addition, overheating of the motor can also cause overheating of the casing.