A soft starter is a solid-state system or device that protects AC electric motors from damage caused by sudden influxes of power by limiting the large initial inrush of current associated with motor startup . They provide a gentle ramp up to full speed and are used only at startup (and stop, if equipped). https://youtu.be/FReoy8R_EMA Specifications: Brand: ABB Model Name/Number: PSR3-600-70 Voltage: 415V AC Frequency: 50Hz Dimensions (W x D x H): 45 x 140 x 114 mm Weight: 0.4 Kg Communication: Filed Bus Plug Terminal Type: Screw Terminals Connecting Capacity Main Circuit: Rigid 1/2x0.75 to 2.5 mm2 Tightening Torque: Main Circuit 1 Nxm, Supply Circuit 1 Nxm, Control Circuit 1 Nxm Operating Temperature: n -25 to +60 degrees C Rated Operational Voltage: 208 ... 600 V AC Rated Control Supply Voltage (U s ): 100 ... 240 V AC Rated Control Circuit Voltage (U c ): 24 V DC Rated Frequency (f): 50/60 Hz Main Circuit 50 / 60 Hz Rated Operational Power - In-Line Connection (Pe): (230 V) 0.75 kW (400 V) 1.5 kW (500 V) 2.2 kW Rated Operational Current - In-Line Connection (Ie): 3.9 A Package Include: 1 x ABB Soft Starter PSR3-600-70 Lotted