For the energy-saving application program of the air compressor industry, this article mainly introduces from two aspects, one is the working principle of the air compressor, and the other is an overview of the energy-saving application scheme of the air compressor industry.
The working principle of the air compressor:
The compressor is directly driven by the electric motor to cause a rotational motion of the crankshaft, and the connecting rod is caused to cause the piston to reciprocate, causing the cylinder volume to change. Due to the change of the pressure inside the cylinder, the air enters the cylinder through the air cleaner (muffler) through the intake valve. During the compression stroke, the compressed air passes through the exhaust valve due to the reduction of the cylinder volume, and the exhaust pipe is single. The valve (check valve) enters the gas storage tank, and when the exhaust pressure reaches the rated pressure of 0.7 MPa, it is automatically stopped by the pressure switch control. When the pressure of the gas storage tank drops to 0.5--0.6MPa, the pressure switch automatically starts to start.
Air compressor industry power saving application program:
The compressor includes an air-conditioner refrigerating main engine and an air compressor. Its operating characteristics are continuous operation 24 hours a day under both loading and unloading conditions, one of 365 days a year without stopping, and one of the most power-consuming motors. At present, the constant voltage control method adopts two control modes: speed regulation and non-speed regulation.
No speed control.
If the compressor is not controlled by constant voltage control, the efficiency of the asynchronous motor is about 87% when the load is running, and the power factor is about 85% (depending on the motor power and load rate); the motor is used by the unloading method. The no-load operation, the efficiency of the motor is only about 30%, and the power factor is also lower than 40%. It is a very uneconomical operation mode, but because the motor does not allow frequent starting, it is only for the user to bear the loss of operation.
After using the motor king permanent magnet synchronous motor product, the customer's power consumption can be completely changed. The efficiency of the motor king is about 95% when loading, and the power factor is about one. At the time of discharge, the efficiency of the motor king is still about 93%, and the power factor is about 90% ahead. It is just a phase-in capacitor, which can compensate the backward power factor of the factory. The power saving effect can be estimated based on the load factor.
Many customers want to change the compressor to the speed control mode as constant voltage control, but generally use the case of inverter drive with few successes. The main problem is that the inverter and asynchronous machine have small starting torque and often cannot start smoothly. Add pressure.
The above problem can be easily solved by using a permanent magnet brushless DC motor product, because the starting torque of the brushless DC motor is larger than the full-voltage starting of the three-phase asynchronous machine, and naturally there is no problem of starting. At the same time, the asynchronous motor after the inverter is used because of the harmonic problem, which makes the efficiency lower. The harmonics of the inverters of different manufacturers are different, and the losses are different, but the efficiency of the inverter plus the asynchronous motor does not exceed 80% in total; The efficiency of the brushless DC motor can reach about 93%, so the power saving effect is obvious; it is the most suitable driving motor for today's compressors.