What this PST50 soft starter delivers
The 1SFA895005R7000: Built-in electronic overload protection (adjustable 1.5-7x Ie) eliminates the need for a separate overload relay, saving DIN-rail space and wiring time. The ramp time is adjustable from 0 to 120 seconds, with initial voltage during start settable between 30-70%, and a step-down voltage special ramp from 100-30% for gentle deceleration on pumps or conveyors. Four signal relays are built in — run, fault, bypass, and overload — each providing a dry contact for the PLC or annunciator. A red LED indicates a fault condition; a yellow LED signals protection activation. The FieldBusPlug (standard) communication interface allows direct connection to a fieldbus network without an extra gateway module.
Screw terminals on the control circuit (1 x 2.5 mm² rigid) and main circuit (1 x 10-95 mm² rigid) match standard panel wiring practices. Tightening torque for the control circuit is 0.5 N·m — a common value for spring-clamp or screw terminals on PLC and relay outputs. The main terminals carry an IP10 degree of protection per IEC 60529 and IEC 60947-1, meaning they are finger-safe against accidental contact but not sealed against moisture — mount in a clean, dry enclosure. The inside-delta connection switch is built in, so you don't need external contactors for that wiring topology. This is the configuration that delivers the higher 85 A / 45 kW rating — useful for larger motors where the in-line rating would be undersized.