Integrator's Note — SIRIUS 3RT1044-3AK60-1AA0
The Siemens 3RT1044-3AK60-1AA0 is a SIRIUS power contactor in the size S3 frame, rated for motor switching at 37 kW on a 500 V AC-3 supply — that's the headline figure for conveyor, pump, or fan duty where the load is inductive and the switching frequency is moderate. Coil is dual-frequency rated: 110 V at 50 Hz and 120 V at 60 Hz, with an operating range of 0.8 to 1.1 times the rated voltage at either frequency — so it holds in during brownout conditions down to about 88 V at 50 Hz. Screw-type terminals on the main circuit accept 2x (10 to 50 mm²) stranded cable; auxiliary contacts are rated 10 A at 24 V, stepping down to 0.3 A at 220 V — enough for PLC-level signal switching but watch the DC derating curve if you're breaking inductive DC loads.
Side-by-side mounting is permitted, which keeps the panel width tight; the 70 mm width per unit means a row of four occupies 280 mm of rail space. IP20 on the front with cover or box terminal; the terminal area itself is IP00 — standard for screw-clamp contactors, but plan for a finger-safe cover if the panel is live during maintenance.
At AC-3 duty the maximum switching rate is 1000 cycles per hour, so it handles frequent start-stop cycles on a conveyor without exceeding the thermal limit of the coil.
AC-3 (motor starting) rating is 37 kW at 500 V and 18.6 kW at 690 V — the lower voltage yields higher current capacity, so size the contactor for the line voltage you actually have. AC-1 (resistive heating) maximum switching rate is 1000 cycles per hour; AC-4 (plugging/inching) drops to 300 cycles per hour — the inrush and breaking duty on AC-4 generates more arc energy, so the contactor needs longer cool-down between operations. Auxiliary contact ratings span 10 A at 24 V down to 0.3 A at 220 V, with a 30 W limit at 1000 V — fine for signaling a PLC input or driving a small relay, but not for direct motor control.