Rated for the motor load, not just the bus
The ABB PSTB570 soft starter (1SFA895017R7000) is rated 570 A in-line connection, delivering 315 kW at 400 V — that is the continuous motor current it handles without bypass. Wired inside-delta, it manages 987 A and 540 kW at 400 V, which is the configuration for larger motors where the starter sees only phase current. Control is 24 V DC, so it integrates directly with a standard PLC or safety relay output without an interposing interface. The unit carries built-in electronic overload protection (I²t model) and a current limit function adjustable from 1.5 to 7× Ie, so you can set the stall protection to match the motor's thermal damage curve. Ramp time is configurable 0 to 120 seconds, with initial voltage during start from 30 to 70 % and a step-down voltage special ramp from 100 to 30 % — enough shaping for high-inertia loads like centrifuges or crushers.
Fieldbus and signal feedback
Communication is via the standard FieldBusPlug — ABB's modular connector that accepts PROFIBUS, DeviceNet, or CANopen inserts depending on the network card fitted. The starter reports run, fault, bypass, and overload status through dedicated signal relays, plus a 0–10 V analog output for current or ramp tracking. A red LED indicates a fault condition; a yellow LED signals protection activation.
This is not an NRND or end-of-life line. For a critical-spare holding on a legacy install, this is one you can still buy new without chasing surplus.
Termination and environment
Main circuit terminals are bars with a 12.5 mm hole diameter — expect M10 or M12 hardware for cable lugs. Control circuit terminals accept 1 x 2.5 mm² rigid and tighten to 0.5 N·m. The main terminals are IP00 per IEC 60529, so the starter requires enclosure mounting for anything beyond a clean, dry panel. Operating ambient is 0 to +50 °C with a 115 % service factor for occasional overload.