Zibo Jiaxin Electric Equipment Co., Ltd.



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Contact: Kong Zong
Contact number: 13605337718
Contact the fixed line: 0533-7077456
Address: No. 2926, Xinhua Road, Linzi District, Zibo City

Introduce the difference between soft starter and frequency converter

Edit:Zibo Jiaxin Electric Equipment Co., Ltd.UpDate:2018-11-21

Although the application of the inverter has been widely used, there are still many people who know nothing about the difference between the soft starter and the inverter. The following Zibo Jiaxin Electrical Equipment Co., Ltd. will introduce you in detail from the roles and principles of the two products.

The working principle of the inverter is to convert the power frequency power supply ( 50Hz or 60Hz ) into AC power of multiple frequencies to realize the variable speed operation of the motor. In this way, the control of the main circuit can be controlled by the circuit, the rectifier circuit converts the alternating current into direct current, the direct current intermediate circuit smoothes the output of the rectifier circuit, and the inverter circuit converts the direct current into an alternating current (and the intermediate control circuit realizes: the process of crossing straight lines) . The frequency conversion process was born to meet the needs of AC motor stepless speed regulation.


The soft starter is actually a motor control with soft start of the motor, soft stop, light load energy saving and many protection functions. It is primarily a three-phase shunt thyristor connected in series between a power supply and a controlled motor and its electronic control circuitry. By controlling the conduction angles of the three opposing parallel thyristors, the input voltage of the controlled motor will vary according to different requirements, thereby achieving many functions.


The inverter is mainly used in occasions where speed regulation is required. Its output not only changes the voltage, but also changes the frequency at the same time ; the soft starter is actually a voltage regulator. When the motor starts, the output only changes the voltage and does not change the frequency. The inverter manufacturer emphasizes that the inverter has many soft-start functions, but its price is higher than that of the soft starter and the structure is more complicated.


Soft starters are used where it is necessary to reduce the starting and stopping pressures. At this time, the motor speed does not change ; but the inverter is mainly used for speed regulation and constant voltage, and the speed is determined by the frequency. The inverter manufacturer believes that the difference between the two is that the inverter can set the operating frequency arbitrarily, but the soft starter only functions as a soft start and a soft stop.