Why Choose a Soft Starter?
As we all know, the direct starting current of motor is 4-7 times rated current, the motors with a low power (generally lower than 7.5kW) have few influences on power grid and are allowed to start directly, but the large motors with high power (rated current 100A) have the instantaneous current of hundred of amperes and are not allowed to start directly because such high current has a high impact on power grid and can influence the normal work of other loads on the same power grid.
The situation is common. For example, when a large load starts, the bulb suddenly darkens. We sometimes have a similar situation at home such as open the TV, sometimes will suddenly dark the bulb. The starting current of load is too high and unfavorable for the insulation of machine winding, so large motor should adopt soft start. Soft start means the voltage at the initial stage of starting is lower than rated voltage.
The common soft start includes start of soft starter and stepdown start of autoformer. Stepdown start of autoformer means that 60%-80% of rated voltage is provided for motor at the beginning of starting of motor to make it operate, and when motor operates, provide the rated voltage for it, which is simple soft start process. And soft starter is more advanced than stepdown start of autoformer although they have the same principle. ATO soft starters are available with 10 hp to 300 hp power capacity which increase their voltage gradually from 0 to rated voltage for motor, so their starting are more smooth, have better effects and least impact and damages to power grid and winding and are better than stepdown start of autoformers. Those are the advantages of ATO soft starters in industrial application. Why not choose a soft starter on ATO.com?