Fixed speed air compressor: the motor is started with star-delta buck, which cannot be constant pressure and wastes electricity.
Variable speed air compressor: the motor is started and adjusted with a inverter, which can be constant pressure and save energy. You can understand by looking at the the following two analog wiring diagrams of air compressors.
Permanent magnet variable speed air compressor is an energy-saving air compressor technology officially promoted nationwide in 2011. The main difference between permanent magnet variable speed screw air compressor and fixed speed screw air compressor:
1. From the perspective of the service life of the machine, the permanent magnet variable speed screw air compressor is better. Because it is driven by a inverter, when the air compressor is started, it uses a "soft start", which has a certain protective effect on the motor and reduces the possibility of burning the motor.
2. From the perspective of parts, the permanent magnet variable speed air compressor adopts a high-efficiency rare-earth permanent magnet motor and a inverter. These two units are of great help to the energy saving of the air compressor.
3. From the perspective of maintenance costs, permanent magnet motors do not require bearings, no need to add grease, which eliminates the point of failure and reduces maintenance costs.
The difference between fixed speed air compressors and variable speed air compressors:
1. The start of fixed speed air compressor generally adopts direct start or star-delta buck start, which has a certain impact on the power grid. The air compressor driven by the inverter is driven by the inverter with soft start function, which is basically no impact on the power grid.
2. The operating mode of fixed speed air compressor is load--unload；
Variable speed air compressor can realize the constant pressure air supply according to the actual working conditions.
The difference between permanent magnet variable speed air compressor and fixed speed screw air compressor:
1.The driving motor is different，the former is a three-phase permanent magnet synchronous motor, and the latter is a three-phase asynchronous motor.
2.The driver is different, it is the inverter. The former is a permanent magnet synchronous special drive, and the latter may be a star-delta buck start or a fixed speed three-phase asynchronous motor drive.
3.The control system may be different.
Features of variable speed air compressor:
1.The essence of permanent magnet high-efficiency variable speed is to control the rotation of the spatial magnetic field of the motor.
2.The stator winding generates a rotating magnetic field synchronized with the frequency of the power supply through three-phase alternating current.
The basic composition of a permanent magnet synchronous motor:
Permanent magnet variable speed screw air compressors have emerged in the last two years. What is the difference between permanent magnet variable speed screw air compressors and fixed speed variable speed screw air compressors? Why is the price difference so much. Both of them are equipped with inverters,the main difference is in the motor:
1.First of all, it is reflected in the motor. The fixed speed motor is generally an asynchronous motor, and the variable speed motor is a synchronous motor;
2.The fixed speed motor has a constant speed, even if the air compressor does not need to be pumped, the motor is still running at the rated speed. (doing useless work and power consumption phenomenon);
3.The speed of the variable speed motor is not constant,when the air compressor is not pumping air, the frequency of the motor will decrease, the speed will decrease, and the input power will decrease to achieve energy saving;
4.Compared with the fixed speed motor, the variable speed motor can reduce the energy consumption by 15% per 1kW;
5.The start-up of the variable speed motor is the start of the inverter, which can be started smoothly.Compared with the star-delta and direct start of the fixed speed motor, the variable speed start can greatly reduce the impact of the starting current wave on the power grid.
The biggest difference between permanent magnet variable speed and variable speed lies in the motor: the permanent magnet motor has a permanent magnet ring, while the variable speed screw compressor is a fixed speed motor，the magnet coil releases a magnetic field when it is energized, generating Lorenz force，under the same power situation, it saves electricity than variable speed. By looking at the main engine, the permanent magnet main engine is in the shape of a circle, and the magnet ring inside can be seen through the vents. The fixed speed main engine sees the wind blade inside.
It mainly depends on your factory's production time, air consumption, and working conditions. Take a 55kW air compressor as an example,if your factory has a production time of 8 hours, the air consumption is unstable and it is recommended to purchase,if the air consumption is stable,and uninstall it infrequently,it is recommended to find a professional manufacturer to test the specific power before making a decision. If the air used for production in your factory is no matter stable and unstable, it is recommended that you find a professional manufacturer to test the specific power, maybe a 37kW double-stage permanent magnet variable speed air compressor can meet the air consumption of your factory.
Fixed speed :habit is the frequency of our mains power 50Hz/sec.
Variable speed:use technology and equipment to increase the frequency of the mains power to save space and equipment weight, especially when a large number of electronic technologies enter the DC low-pressure power supply. It is more widely used in all aspects: energy-saving lamps、LED lights、mobile phones and computer power supply、 PLC fixed control, etc.The difference is only the change in frequency.
For more than a decade, Dream （Shanghai） Compressor Co., Ltd has been striving to become one of the leading manufacturers of compressed air solutions in China.