There are significant differences between variable frequency screw air compressors and power frequency driven air compressors in terms of operation mode, energy efficiency performance, pressure stability, starting characteristics, noise level, maintenance cost and applicable scenarios, as follows:
1. operation mode
- frequency conversion screw air compressor: The motor speed is dynamically adjusted by the frequency converter to realize on-demand air supply. When the gas consumption changes, the motor speed is automatically adjusted, and the displacement changes accordingly to avoid energy waste.
- Power frequency driven air compressor: The motor runs at a fixed speed, and the displacement is controlled by adjusting the opening of the intake valve. When the gas consumption changes, the opening of the intake valve changes, but the motor speed remains the same, resulting in higher energy consumption at low load.
2. energy efficiency performance
- frequency conversion screw air compressor the energy saving effect is remarkable, and the average energy saving rate can reach more than 30%. At low load operation, the motor speed is reduced and the power consumption is reduced. At full load, the permanent magnet motor produces the maximum gas volume at the minimum energy consumption, and the operating efficiency is as high as 95% when the load rate is less than 20%.
- Power frequency driven air compressor high energy consumption, especially in low load operation. Because the motor speed is fixed, that is, the use of gas is low, the motor is still running at full power, resulting in a waste of energy.
3. pressure stability
- frequency conversion screw air compressor using the stepless speed regulation characteristics of the frequency converter, combined with the PID regulator, the precise control of the system pressure is realized. Even if the gas volume fluctuates greatly, the pressure can be maintained stable, and the fluctuation range is usually controlled within ± 0.01~0.1 MPa.
- Power frequency driven air compressor: Large pressure fluctuations are usually buffered by large gas tanks, increasing system complexity and installation costs.
4. Startup Characteristics
- frequency conversion screw air compressor using soft start technology, the maximum starting current is within 1.2 times of the rated current, which has little impact on the power grid and prolongs the service life of the equipment.
- Power frequency driven air compressor the star-delta starting mode is adopted, and the starting current can reach 5-8 times of the rated current, which has a great impact on the power grid and may affect the safe operation of other electrical equipment.
5. noise level
- frequency conversion screw air compressor: The speed is adjustable during operation, usually lower than the rated speed, and the soft start function of the inverter reduces noise and vibration, and provides more comfort for the working environment.
- Power frequency driven air compressor the running speed is constant and the start and stop are frequent, and the mechanical impact is large, resulting in obvious noise and vibration, which will affect the working environment and personnel health.
6. maintenance costs
- frequency conversion screw air compressor: Although the initial investment is higher, the operation is more stable, the equipment wear is small, and it has the effect of energy saving, and the long-term use is more cost-effective. Real-time monitoring and troubleshooting capabilities further reduce maintenance requirements and downtime.
- Power frequency driven air compressor: The structure is simple and the manufacturing cost is low, but the equipment wears faster and the failure rate is higher due to the operation mode, which increases the maintenance cost and the risk of downtime.
7. applicable scenarios
- frequency conversion screw air compressor: It is suitable for scenes with large fluctuations in gas consumption and high requirements for pressure stability, such as automated production lines, medicine, electronic manufacturing, food processing and other industries.
- Power frequency driven air compressor: It is suitable for occasions that are sensitive to cost and do not require high air quality, such as some ordinary factory production lines or construction sites.
