The most commonly used in transmission engineering today is the three-phase AC induction motor. In many cases, due to its starting characteristics, these motors surge directly to the power supply system. If started directly online, a surge current up to 6 times the rated current for the motor will be generated. This current overloads the power supply system and the switching equipment in series.If started directly, a high peak torque is also generated, which will not only impact the drive motor, but also damage the use of the mechanism. For example: auxiliary power transfer (v-belt, gear). In order to reduce the direct current, starting aids, such as starting electric reactors or self-coupled transformers, but the use of reactors or self-coupled transformers and other conventional methods can only gradually reduce the voltage, and the soft starter by smoothly raising the terminal voltage, can achieve a shock-free start. As a result, the power supply system and the motor can be optimally protected.
Soft starter is a novel motor control device that integrates soft starting, soft parking, light load energy saving and a variety of protection functions. Its main composition is to string the three opposite parallel gate tube and its electronic control circuit between the power supply and the charged motor. Using different methods, control the on-on angle of the three opposite parallel gate tubes, so that the input voltage of the charged motor varies according to different requirements, different functions can be realized.
In fact, the soft starter is the equivalent of a regulator, and when the motor is started, the output changes only the voltage and does not change the frequency. It is easy to install and adjust, and all control connections and parameter adjustments are done on the front. The soft starter can still be easily retrofitted in place after installation, such as additional current limiting functions and internal/external conversion options. The soft starter can operate continuously online without bypass. The soft starter sets up a separate control relay for bypass and fault. All parameters of the soft starter are set by the three knob potometers and one uncode switch on the panel for intuitive accuracy. Can be widely used in textiles, metallurgy, petrochemicals, water treatment, shipping, transportation, medicine, food processing, mining and machinery and equipment industries.