Soft starter for motor starting duty
The ABB 1SFA895016R7000 is a PSTB470 soft starter rated for 470 A inline (Ie) and 814 A inside-delta connection, delivering 250 kW at 400 V in inline configuration or 450 kW inside-delta. The 24 VDC control circuit powers the logic, and the 0–120 second ramp time lets you tune acceleration for pump, fan, or conveyor starts without mechanical shock. Built-in electronic overload protection eliminates the need for a separate thermal relay — one device handles both starting and running protection.
The 470 A inline rating covers most 250 kW motor loads at 400 V — that's a standard IEC frame size for medium-voltage soft starts. The inside-delta connection nearly doubles the current capacity to 814 A (450 kW) by placing the thyristors in the motor delta legs rather than the line, which is useful when the motor's full-load current exceeds the inline rating but the line current stays lower. The 24 VDC control voltage is the common PLC-level signal; verify your cabinet's 24 V supply can deliver the inrush for the coil. The 0–120 s ramp range handles soft starts for high-inertia loads like centrifuges or long conveyors, while the 30–70 % initial torque setting lets you set the breakaway torque just above load friction.
Main circuit terminals are bars with a 10.5 mm hole diameter — expect M10 or 3/8" bolted connections for the power cables. Control circuit wiring accepts 1 x 2.5 mm² rigid conductors, torqued to 0.5 N·m. The unit includes run, fault, bypass, and overload signal relays for status feedback to the PLC. Communication is via a standard FieldBusPlug — no built-in fieldbus protocol; the plug accepts a separate communication module if network integration is needed. The IP00 rating on the main terminals means the soft starter is intended for enclosure mounting; it is not a standalone outdoor unit.