SIRIUS S0 power contactor, 48 VDC coil
The Siemens 3RT1026-1BW44 is a SIRIUS-branded power contactor in frame size S0, designed for switching motor loads in industrial control panels. It is rated for 11 kW at AC-2 duty at 400 V, and carries a 15.5 A rated operational current at AC-4 at 400 V — the AC-4 figure governs reversing or inching applications where the contactor makes and breaks stalled rotor current, so that is the number to size against for plugging or jogging duty. The coil is rated 48 VDC, with a closing and holding power of 5.4 W. The DC coil holds continuously at rated voltage; verify your control transformer or power supply can deliver the inrush without droop below the dropout threshold. Mounting is screw and snap-on onto 35 mm standard mounting rail per DIN EN 50022. The 45 mm wide body fits a standard 45 mm slot on the rail, and side-by-side mounting is permitted without derating for the thermal current — a real space saver in dense panels.
Environmental and lifecycle
Ambient temperature range during operation is -25 to +60 °C, with a pollution degree of 3 (conductive pollution or dry non-conductive pollution that becomes conductive due to condensation). This is typical for industrial environments but means the contactor should be mounted in a clean, dry enclosure if condensation is expected. The mechanical service life is typically 10,000,000 switching cycles. Electrical life depends on the load and switching frequency; the AC-1 maximum operational current is 10 A, which covers resistive loads like heaters.