Application of Laeg LD500 series inverter in Screw Air Compressor

I. Overview of Screw Air Compressor

Air compressor is the basic product of industrial modernization, which provides air power and is the main part of the electromechanical air-entraining source device, which is the core equipment of pneumatic system. It is a device that converts the mechanical energy of prime mover (usually motor) into gas pressure energy and is compressed air.

Air pressure generating device.

Second, the working principle of screw air compressor

The screw air compressor is a positive displacement gas compressor, and the compression of air depends on the male and female rotors which are engaged in parallel in the casing.

(i.e. screw), casing and exhaust valves properly arranged at two air inlets and outlets constitute a working chamber for compressing gas, and the gas pressure is increased by reducing the working volume. The rotor pair rotates in the casing which is closely matched with it, so that the gas seen in the rotor cogging constantly produces periodic volume changes, and along the rotor axis, it is pushed from the suction side to the discharge side, completing three working processes of suction, compression and exhaust. The gas enters the inter-tooth volume of the male and female rotors respectively through the air inlet. During the rotation of the rotor, the teeth of the male and female rotors are continuously filled into the opposite tooth slot, and the tooth slot of the working cavity is constantly pushed to the exhaust end, so that the volume is gradually reduced and the gas is compressed. When the compression volume is communicated with the exhaust port, the gas has reached a predetermined pressure and is discharged, completing a working cycle.

Three, the traditional screw air compressor using site characteristics

In order to meet the requirement of changing gas consumption at any time, the gas in the gas storage tank must maintain a certain pressure. At present, most traditional screw air compressors adopt the adjustment method of cutting off the air intake to change the gas discharged to the gas storage tank. The relationship between the supply and demand of air compressor's gas volume is manifested as the change of exhaust pressure. When the air compressor's exhaust volume just meets the production gas consumption requirements, the gas storage pressure remains unchanged. If this state can be maintained, of course, it is good, but in fact, the gas consumption changes at any time and the design redundancy is large, so the air compressor's exhaust volume is greater than the gas consumption. If the air compressor is still running at a constant speed, the gas in the gas storage tank will accumulate more and more. When the pressure in the tank rises to the set pressure, Generally, there are two methods: one is that the air compressor is unloaded and does not produce compressed gas, and the motor is in no-load operation, and its electricity consumption is still 30-60% of the full load, which is wasted in vain. Another way is to stop the operation of the air compressor, so it seems that the wasted electric energy caused by idling or continuous emptying of the air compressor is eliminated. However, if there is no gas storage tank with large volume, the motor will be frequently started, and the no-load starting current of the air compressor is about 5-7 times of the rated current, which has a great impact on the power grid and other electrical equipment, and at the same time, the service life of the air compressor will be shortened.

Four, JAC Lange variable frequency air compressor system scheme:

4.1 JAC Electric and its subsidiaries can provide products for customers.

4.2 Comparison of various driving configurations of air compressor

4.3 electrical principle