The Siemens 3RB2066-2MF2 is a SIRIUS solid-state overload relay rated for 630 A operational current with a CLASS 20E trip characteristic. It's designed for motor protection in industrial control panels, typically mounted directly to a contactor or as a standalone unit using the M10 main contact fastening. The auxiliary switch is integrated, and the relay handles AC motors from 132 to 400 kW at 500 V / 50 Hz.
Mounts in any position via contactor mounting or standalone installation. The 155 mm depth, 120 mm width, and 119 mm height fit standard panel layouts. Main current circuit uses busbar connection; solid or stranded wire 2x (0.25... 1.5 mm²) for the control terminals. Rated impulse withstand voltage 1 000 V for AC-3e duty. Thermal current rating 630 A. Vibration resistance per IEC 60068-2-27: 15g / 11 ms shock, signaling contact in tripped position rated 8g / 11 ms.
Operating frequency 50... 60 Hz. Storage and transport temperature range -40 to +80 °C. The relay is designed for global use with voltage ratings covering 24 V (2 A), 120 V (4 A), 230 V (3 A), and others across the auxiliary contact set.