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Shanghai Linjiang Water Plant-Backwashing Air Compressor Frequency Conversion Sp

Background introduction:  

  The main motor power of the original air compressor of this factory is 11KW, and the operating mode is star-angle decompression starting, which is heavier than full pressure operation

  The working principle of the air compressor is that a pair of male and female rotors (or screws) that are toothed parallel to each other rotate in the cylinder, so that the air between the rotor teeth continuously produces periodic volume changes, and the air is changed along the axis of the rotor. The suction side is transported to the output side to realize the whole process of suction, compression and exhaust of the screw air compressor. The air inlet and the air outlet of the air compressor are respectively located at both ends of the casing, and the slots of the female rotor and the teeth of the male rotor are driven to rotate by the main motor.

Working principle of air compressor
Problems existing in the original system operating conditions:
  1. Although the air compressor starts at star-corner decompression, the current at starting is still large, which will affect the stability of the power grid and the safety of other electrical equipment.
  2. Air compressors often run at no-load, which is non-economic operation and wastes electricity.
  3. The power frequency operation of the air compressor causes a lot of noise during the operation of the air compressor.
Frequency conversion solution:
    The frequency conversion transformation adopts DANFOSS frequency converter, one frequency converter controls 4 air compressors, and the system designs two main circuits of frequency conversion and industrial frequency. Two sets of control loops, closed loop and open loop, are adopted. The pressure closed-loop control system composed of frequency converter, pressure transmitter, motor and spiral rotor automatically adjusts the motor speed to stabilize the air pressure in the air storage tank within the set range and perform constant pressure control. The feedback pressure is compared with the set pressure, and the output step of the inverter is controlled in real time to adjust the motor speed to stabilize the air pressure in the air storage tank at the set pressure.
Final Results: 
    After the frequency conversion transformation, the system automatically adjusts the operation of the air compressor according to the demand for air consumption. Greatly reduce operating costs. Improve the accuracy of pressure control; extend the service life of the compressor and reduce the noise of the air compressor.

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