PSTX37 — fieldbus-ready soft starter with auto phase sequence
The ABB 1SFA898104R7000 is a PSTX37 soft starter rated for 208 to 600 V AC at 50/60 Hz, with a built-in electronic overload and auto phase sequence detection that protects the motor during commissioning — no separate phase monitor needed. Ramp time is adjustable from 1 to 120 seconds, covering most induction-motor start profiles from low-inertia fans to high-inertia conveyors. Control supply is 100 to 250 V AC; the control circuit itself runs on 24 V DC, so the PLC or safety relay can drive it directly without an interposing relay. The main terminals accept cable clamp connections with an 8.5 mm hole and a tightening torque of 8 N·m.
Protection and warnings — what is covered
This soft starter includes built-in electronic overload protection with dual overload curves — separate settings for start and run — plus earth fault / ground fault protection, locked rotor protection, phase reversal protection, overvoltage and undervoltage protection, and voltage imbalance protection. It also accepts PTC thermistor inputs for direct motor temperature monitoring. Warning outputs cover current imbalance, underload, electronic overload time-to-trip, end-of-life, faulty fan, locked rotor, motor runtime limit, overvoltage, phase loss (standby), power factor underload, short circuit (limp mode), THD(U) harmonic distortion, thyristor overload, undervoltage, and voltage imbalance. Three signal relays (run, fault, bypass, overload) provide dry-contact status to the controller.
Fieldbus and analog interface
The PSTX37 supports Modbus-RTU, Modbus-TCP, Ethernet/IP, EtherCAT, DeviceNet, CANopen, Profibus, Profinet, BACnet-IP, and BACnet-MSTP — one unit covers nearly any plant-floor network without a separate gateway. Analog outputs are configurable for 0–10 V, 0–20 mA, or 4–20 mA, so the starter can feed a drive speed reference or a remote SCADA indication.
No last-time-buy or end-of-life notice applies.