The difference between soft start and frequency conversion start of screw air compressor

The soft start and frequency conversion start of screw air compressor are two different starting methods, and there are significant differences in the starting principle, functional characteristics and application effect. The following is a detailed comparison of the two startup methods:

1. starting principle

1. soft Start

   • principle: Soft starter is a motor control device that integrates motor soft start, soft stop, light load energy saving and multiple protection functions. It controls the conduction angle of the three-phase anti-parallel gate connected in series between the power supply and the controlled motor, so that the input voltage of the controlled motor changes according to different requirements, so as to realize the smooth start of the motor.
   • Features: The soft starter is actually a voltage regulator, which only changes the voltage without changing the frequency when the motor starts. When starting, the voltage gradually rises from zero until it reaches the rated voltage to realize the smooth start of the motor.

2. Variable frequency start

   • principle: The frequency converter is a converter that converts alternating current with fixed voltage and frequency into alternating current with variable voltage and frequency. It adjusts the speed of the motor by controlling the output voltage and frequency, so as to realize the start and speed regulation of the motor.
   • Features: Variable frequency start not only changes the voltage, but also changes the frequency at the same time. The frequency converter has all the functions of the soft starter, and can realize the stepless speed regulation of the motor, so that the motor can maintain the best state in the process of starting and running.

2. features

1. soft Start

   • advantages: Soft start can significantly reduce the current impact when the motor starts, reduce the risk of grid fluctuations and equipment damage. At the same time, it also has a variety of protection functions, such as overload protection, phase loss protection and overheat protection, which improves the safety and stability of the motor.
   • Disadvantages: Soft start can only realize the smooth start of the motor, and cannot adjust the speed of the motor. In addition, a certain amount of heat and noise may be generated during the soft start process, which has a certain impact on the life of the machine.

2. Variable frequency start

   • advantages: Variable frequency start not only has all the advantages of soft start, but also can realize the stepless speed regulation of the motor, so that the motor can maintain the best state during starting and running. In addition, the frequency converter can also adjust the speed and output power of the motor according to actual needs to achieve energy saving effect. The variable frequency start can also slow down the impact on the equipment, reduce the amount of maintenance and repair, and reduce the cost of operation and maintenance.
   • Disadvantages: The cost of frequency conversion start is relatively high, and the structure is more complicated. At the same time, it has higher requirements for the use of the environment, such as the need for stable power supply and appropriate temperature.

3. application effect

1. soft Start

   • application occasions: Soft start is suitable for occasions where there are strict requirements on the starting current and no speed regulation is required. Such as air compressor, water pump, fan and other high-power equipment start.
   • Effect soft start can significantly reduce the impact of starting current, reduce the risk of power grid fluctuations and equipment damage. At the same time, it can also improve the safety and stability of the motor.

2. Variable frequency start

   • application occasions: Variable frequency start is suitable for occasions where speed regulation is required and energy saving effect is required. Such as screw air compressor start and speed regulation, industrial automation production line.
   • Effect: Variable frequency start can not only realize the smooth start of the motor and stepless speed regulation, but also significantly improve the energy saving effect. At the same time, it can also slow down the impact on the equipment and extend the service life of the equipment.

In summary, there are significant differences in the starting principle, functional characteristics and application effect between the soft start and the frequency conversion start of the screw air compressor. When choosing the starting method, it should be evaluated and selected according to actual needs.