The Siemens 3RB3046-2UW1 is a SIRIUS solid-state overload relay, size S3, designed to protect motors against overload and phase failure in 50-60 Hz AC circuits. Its CLASS 20E trip class means it allows a 20-second cold-start acceleration before tripping — a good fit for conveyors, pumps, and fans with moderate inertia. The electronic overload release gives accurate, drift-free protection without the heating hysteresis of a bimetal relay.
The auxiliary switch is integrated and rated for switching at various control voltages: 2 A at 24 V, 4 A at 120 V, 3 A at 230 V — these are the contact ratings for the signaling contact, not the main power path. The main circuit uses straight-through transformers, meaning the motor leads pass directly through the relay body without looping; this keeps wiring clean and avoids extra bending radius in the panel.
Mounts in any position — stand-alone installation on a flat panel or DIN rail. Dimensions: 70 mm wide, 106 mm high, 124 mm deep. That 124 mm depth means it sticks out a bit from the rail; check clearance to the enclosure door or adjacent devices. Vibration resistance: 1-6 Hz at 15 mm amplitude, 6-500 Hz at 20 m/s², 10 cycles — solid for industrial panels on machine frames. Shock resistance: 8g / 11 ms for the signaling contact in tripped position, 15g / 11 ms for the relay body.