Direct starting full pressure when the starting torque is about 2 times of the rated torque, so the torque suddenly in the static mechanical equipment, will accelerate the gear wear even fight tooth and accelerate the abrasion of the belt or even pull off the belt, accelerate the wind leaf fatigue or even broken blades etc..
The torque of soft starting will not exceed the rated torque, and the disadvantages can be overcome completely.
When the starting, the harm of only a certain degree of decrease; when the soft start, the harm has almost completely disappeared; independent power supply transformer direct starting only eased in the power grid voltage fluctuations, and other aspects of the hazard still exists.
Ultra large motors are of high value and play a central role in production. One of its faults will cause great economic loss, and it is necessary to adopt perfect protection. For example, we cannot expect a motor on its insulation everywhere are exactly the same, may at some point there is a weak link, it can pass the test, but in a long time under the impact of the weak link will gradually emerge first, to shorten the life span. If we take soft start, it can greatly extend the service life of the motor, which of the two schemes is cost-effective This is obvious.
