What this SIRIUS soft starter delivers
That's the headline number, but the real-world current drops to 62 A at 50 °C and 60 A at 60 °C — so if your panel runs hot, you're sizing off the 60 A figure, not the 72 A. Rated insulation voltage is 600 V, operating frequency is 50 to 60 Hz, and the control supply is 24 V at both 50 and 60 Hz. It uses thyristor stacks for the ramp and an integrated bypass contactor that closes once the motor is up to speed. That bypass means the thyristors only dissipate heat during the start — no continuous heat sink load in run state, which simplifies panel ventilation.
Mounting and wiring reality
Mounting is screw-fix or snap-on onto a DIN rail. The unit is 55 mm wide, 160 mm high, and 170 mm deep — that's a standard S2 footprint. Clearance requirements: 60 mm above, 40 mm below, 30 mm at the sides. If you're packing it into a tight enclosure, those gaps are real — you can't cheat the airflow or the bend radius on the power cables. Main circuit terminals are screw-type, accepting 2x stranded from 1.5 to 25 mm² or 2x solid from 0.5 to 2.5 mm². Auxiliary contacts take 2x conductors from 20 to 14 AWG. The maximum motor cable length is 300 m — relevant if you're feeding a motor at the far end of a plant.
Environmental and operating limits
Storage range is -40 to +80 °C. Mounting position is flexible: with an additional fan you can rotate the unit ±90° on a vertical surface or tilt ±22.5° front-to-back; without the fan, rotation is limited to ±10° and tilt to ±10°. Minimum load is 20% of the rated current — useful to know if you're starting a lightly loaded pump or fan that might not pull enough current for the soft starter to regulate properly.