Siemens SIRIUS 3RB3113-4PE0 Solid-State Overload Relay, S00,

It mounts directly onto a contactor, saving DIN-rail space in the panel. The relay offers adjustable trip classes CLASS 5E, 10E, 20E, and 30E, which means you can match the trip curve to the motor's thermal capacity and starting characteristics — a fast trip for pumps, a slower one for high-inertia loads like fans or conveyors. The thermal current rating is 4 A, with a rated voltage of 690 V. Termination is via spring-loaded terminals on the main current circuit, accepting 2x (0.25... 1.5 mm²) solid or stranded wire. The signaling contact (for message "tripped") is rated at 2 A at 24 V, 4 A at 120 V, and 3 A at 230 V, so it can drive a PLC input or a local indicator directly.

The adjustable trip class is the main selection parameter here. A CLASS 5E trip means the relay will trip within 5 seconds at 7.2x the current setting — use this for motors that start unloaded or have short acceleration times. CLASS 30E gives you 30 seconds at the same multiple, needed for high-inertia loads like centrifuges or large fans. The trip current setting range is defined by the condition IMotor > lower current setting value and IMotor < upper current setting value x 3.5, so the relay can handle motors with a starting inrush up to 3.5 times the set current without nuisance tripping during start. The thermal current rating of 4 A at both 480 V and 600 V rated value tells you the relay's continuous current-carrying capacity is 4 A regardless of line voltage in that range — the voltage rating of 690 V is the insulation withstand, not the continuous current limit. The power dissipation per pole is only 0.03 W, so heat buildup in a tightly packed panel is negligible. Storage and transport range is -40 to +80 °C. Vibration resistance is specified to 1-6 Hz at 15 mm amplitude and 6-500 Hz at 20 m/s² for 10 cycles; shock resistance is 15g for 11 ms, so it holds up on a machine subject to normal industrial vibration.

Mounting is via contactor mounting — the relay clips directly onto the front of a Siemens SIRIUS contactor in size S00. The mounting position is any. The spring-loaded terminals on the main current circuit accept 2x (0.25... 1.5 mm²) solid or stranded wire — no screw tightening needed, which speeds up wiring. The screwdriver shaft diameter for the signaling contact terminals is 5 to 6 mm, with a Pozidriv PZ 2 tip. Dimensions are 45 mm wide, 72 mm high, and 90 mm deep, fitting the S00 footprint.