Difference between soft start and traditional voltage reduction start

Generally, the traditional voltage reduction start ways are: Y-q start, auto voltage reducing start, reactor start etc. These start methods are all step voltage reduction start which have obvious shortcomings, namely occur secondary current impact in starting process. The differences between soft start and the traditional to start ways are:

1) No surge current, during motor starts, the soft starter increase the thyristor conduction angle gradually to make the motor current rises from zero to the set value in linear.

2) Constant current start, soft starters can be applied current closed-loop control to make the motor current keep constant during starting to ensure smooth start.

3) Adjusting optimized starting current in stepless free according to the load characteristic and the power grid protection characteristic.