1, according to voltage classification: high voltage soft starter, low voltage soft starter;
2, according to the classification of media: solid soft starter, liquid resistance soft starter;
3, according to the control principle: electronic soft starter, electromagnetic soft starter;
4, according to the operation mode: Online soft starter, bypass soft starter;
5, according to the load: standard soft starter, heavy-duty soft starter.
The difference between the soft starting and the traditional decompression starting is:
1. No impact current. When starting the motor, the starting current of the motor rises linearly from zero to the setting value by gradually increasing the conduction angle of the thyristor.
2. Constant current starting. The soft starter can introduce the current closed loop control, so that the motor keeps constant current in the starting process, and ensures the smooth starting of the motor. According to the load characteristics and power grid relay protection, can be freely adjusted to the optimum level without starting current. It is suitable for heavy load and needs to overcome larger static friction starting occasion.
Voltage double ramp starting: during starting, the output torque of the motor increases with the voltage,
Soft starter (Figure 3)
Soft starter (Figure 3)
When starting, an initial starting voltage Us is provided, and the Us is transferred to the static friction torque of the load according to the adjustable load, so that the load can start rotating immediately and Us. Then the output voltage starts from Us and increases with a certain slope (the slope is adjustable), and the motor continues to accelerate. When the output voltage reaches the speed voltage of Ur, the motor basically reaches the rated speed. The soft starter automatically detects the up to speed voltage during the starting process. When the motor reaches the rated speed, the output voltage reaches the rated voltage.
