What this SIRIUS soft starter delivers
It handles three-phase induction motors across 50 to 60 Hz, using thyristor-based voltage ramp control to limit inrush current during start-up. The integrated bypass contact system switches the thyristors out once the motor is at speed, eliminating heat dissipation from the power semiconductors during run — a key difference from a straight solid-state starter.
The 50 A rating holds up to 40 °C ambient. Above that, derate to 45 A at 50 °C and 40 A at 60 °C. Maximum operating temperature is 60 °C; storage range is -25 to +80 °C.
Motor protection and control features
Built-in motor overload protection and intrinsic device protection are standard. The adjustable current limitation lets you set the start current between 8% and 100% of the motor FLA — useful for soft-starting conveyors or pumps where a hard start would jerk the load. An external reset input and a fault display (with display) simplify remote diagnostics. The inside-delta circuit wiring option reduces the current through the thyristors by about 42%, letting a smaller soft starter handle a given motor — check if your motor's terminal box supports six-wire delta connection before specifying this mode.
Mounts via screw fixing on a vertical surface, rotatable ±90° and tiltable ±22.5° front-to-back. Clearance requirements: 100 mm above, 75 mm below, 5 mm to the side — tight side clearance helps in a crowded panel. Main circuit terminals are box lugs accepting 2x (10 AWG to 1/0) using both clamping points, or 10 AWG to 1/0 using front or back clamping point singly. Stranded wire range is 2x (4 to 50 mm²). Auxiliary and control circuits use spring-loaded terminals for 2x (24 to 16 AWG). Solid wire for aux circuits is 2x (0.25 to 1.5 mm²). Maximum motor cable length is 500 m — long enough for most plant-floor runs, but watch voltage drop at full load.