Rated for the load, not just the line
The 1SFA895018R7020: The ABB PSTB720 softstarter carries a 720 A rated operational current in-line connection (Ie), good for a 400 kW motor at 400 V. Wired inside-delta, it handles 1247 A — 710 kW at 400 V — because the starter sees phase current, not line current. That inside-delta rating is the one to size for a heavy pump or conveyor start where the motor FLA pushes past 700 A. Ramp time is adjustable from 0 to 120 seconds, with initial voltage during start settable 30–70 % and a step-down voltage ramp from 100 down to 30 %. That range covers soft starting high-inertia loads (centrifuges, long conveyors) where a gradual torque ramp prevents mechanical shock.
Main circuit terminals are bars with a 12.5 mm hole diameter — expect lug connections, not wire ferrules. Control circuit terminals tighten to 0.5 N·m and accept 1 x 2.5 mm² rigid. The supply circuit also takes 1 x 2.5 mm² rigid. Ambient operating temperature 0 to +50 °C; main terminals are IP00 per IEC 60529 and IEC 60947-1, so the starter needs to live inside a panel or enclosure. Communication is via a standard FieldBusPlug — no onboard Ethernet or serial; the plug accepts a fieldbus module (PROFIBUS, DeviceNet, etc.) for network control. Analog output 0–10 V for speed or current feedback to a PLC or drive display.
Protection and signaling
Built-in electronic overload protection with current limit adjustable 1.5–7× Ie. Starting capacity is 3× Ie for 15 seconds. Service factor 115 %. Separate fault, run, bypass, and overload signal relays (each yes) give discrete dry-contact feedback for the PLC or annunciator. Red LED for fault, yellow for protection indication. Switch for inside-delta connection is included on the unit — no external contactor reconfiguration needed when wiring the motor in delta. Rated control supply voltage 100–250 V AC; control circuit also accepts 24 V DC for the logic section.