What it is and what it does
The Siemens SIRIUS 3RT6028-1AQ00 is a S0-size power contactor, part of the SIRIUS family, designed for switching motor loads in industrial control panels. It is rated for AC-3e duty up to 690 V, delivering 27.5 kW at 400 V and 47.5 kW at 690 V at 60 °C — these are the real-world motor-switching numbers that govern fit for a conveyor, pump, or fan circuit. The contactor uses screw-type terminals for both main and auxiliary circuits, and mounts via screw or snap-on onto a 35 mm DIN rail per DIN EN 50022. The S0 frame size and 45 mm width mean it fits standard panel layouts without surprises.
Key ratings and what they mean for fit
The AC-3e rated switching frequency of 750 cycles per hour is the practical limit for motor starting under load — exceed it and the contactor overheats. The AC-1 resistive rating allows 1,000 cycles per hour, useful for heater banks or lighting. The mechanical life of 10 million operations means the coil and armature will outlast most panel rebuild cycles. Rated insulation voltage of 690 V and a pollution degree of 3 (conductive pollution, typical in industrial enclosures) confirm this contactor is specified for ungrounded IT systems and harsh environments. The operating temperature range of -25 to +60 °C covers most indoor panel conditions without derating. The coil draws 6 A at 24 V rated value, 1 A at 110 V, and 0.3 A at 220 V — these are the inrush and hold currents the PLC output or control transformer must supply. The 0.25 power factor at 50 Hz matters for sizing the control transformer VA.
Mounting and integration
Mounts on 35 mm DIN rail per DIN EN 50022, with screw or snap-on fastening. Side-by-side mounting is permitted, so you can gang multiple contactors without spacing — useful for compact motor control centers. The mounting position allows +/-180° rotation on a vertical surface and +/-22.5° tilt, giving flexibility in tight enclosures. Terminals accept 2x (0.5 to 1.5 mm²) or 2x (0.75 to 2.5 mm²) solid or stranded wire, or 2x (16 to 12) / 2x (14 to 8) AWG. The minimum permissible conductor cross-section at both 40 °C and 60 °C is 10 mm², which sets the minimum wire size for the main circuit.
Lifecycle and sourcing reality
The lifecycle stage is marked as current, meaning Siemens continues to manufacture this order code. It is not subject to a last-time-buy or phase-out notice. For a BOM line that calls out 3RT6028-1AQ00, this part is the direct, in-production fit — no substitution needed.