ABB 软起动器PSS系列；PSSL
Soft starter (soft starter) is a new motor control device which integrates motor soft start, soft stop and multiple protection functions. It is called Soft Starter abroad. Its main composition is a three phase anti parallel thyristor connected to the power supply and the controlled motor and its electronic control circuit. Using different methods to control the conduction angle of the three phase anti parallel thyristor and make the input of the controlled motor.
Voltage varies according to different requirements, and different functions can be realized. The soft starter and the frequency converter are two completely different uses. Frequency converter is used for speed control. The output not only changes the voltage but also changes the frequency. 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 frequency converter has all the soft starter functions, but its price is much more expensive than the soft starter and the structure is much more complex. The motor soft starter is used on the soft starter is connected between the power supply and controlled motor, control the turn-on angle of thyristor, the motor input voltage from zero to a preset function increased gradually, until the start end, with full voltage motor, namely soft start, soft start in the process of motor starting torque increased speed is gradually increasing.
The soft start device uses a three phase reverse parallel thyristor as a voltage regulator to connect it to the power of the motor and the stator of the motor. This kind of circuit is a three-phase fully controlled bridge rectifier circuit. When starting the motor with soft starter, the output voltage of the thyristor increases gradually, and the motor accelerates gradually until the thyristor is fully conductive. The motor operates on the mechanical characteristics of the rated voltage, achieving smooth start, reducing starting current and avoiding starting over current tripping. When the motor reaches the rated speed, the startup process end, soft starter thyristor automatic bypass contactor with substituted completion pipe, provide the rated voltage of the normal operation of the motor, to reduce the heat loss of the thyristor soft starter, prolong the service life, improve the work efficiency, but also to avoid network harmonic pollution. The soft starter also provides soft parking function. The soft parking process is opposite to the soft start process. The voltage gradually decreases, and the revolution gradually decreases to zero, avoiding the torque impact caused by free parking.
No shock current
When the soft starter starts the motor, the starting current of the motor is increased from zero linear to the set value by increasing the conduction angle of the thyristor gradually. No impact on the motor, improve the reliability of power supply, smooth start, reduce the impact torque on the load machinery and prolong the service life of the machine.