The Siemens 3RF2430-1AB45 is a SIRIUS solid-state contactor designed for zero-point switching of resistive and lightly inductive loads in AC circuits. It is a two-phase controlled device, meaning it switches two of the three phases in a three-phase system, which is standard for many heater and lighting applications where the third phase can be left connected or switched separately. Rated at 30 A in AC-51 duty (resistive load category per IEC 60947-4-3), it handles a supply voltage range of 48 to 600 V AC at 50/60 Hz. The UL 508 rating is 22 A, which is the value to use for North American panel designs. The minimum operational current is 500 mA, so it is not suited for very low-current signal switching below that threshold. The I²t value is 7200 A²s, which defines the short-time withstand capability for fuse coordination.
Dimensions are 74.5 mm wide, 100 mm high, and 119.5 mm deep, which is a compact footprint for a 30 A solid-state contactor. Side-by-side mounting is permitted, which helps density in a control panel. Main circuit terminals accept 1.5 to 6 mm² solid or stranded wire (AWG 14-10 for two conductors). Control circuit terminals accept 0.5 to 2.5 mm² solid (1x) or 0.5 to 1.0 mm² (2x). All terminals are screw-type, so a screwdriver is needed for termination.
Electrical characteristics and thermal management
Power dissipation is 61 W in the hot operating state (at rated AC current), and standby power is 0.9 W without load. Control current at DC rated value is 30 mA (22 mA at DC). The ON-delay time is 1 ms plus a maximum of one half-wave, which is typical for zero-point switching — the load turns on at the next zero crossing after the control signal is applied.