The Siemens 3RB3026-1PE0 is a SIRIUS solid-state overload relay — an electronic overload protection device for motor circuits, designed to mount directly onto a contactor (contactor mounting). It is rated for a thermal current of 4 A and a rated insulation voltage of 690 V, with a CLASS 10E trip class, meaning it will trip within 10 seconds at 7.2× the current setting, protecting motors against sustained overloads without nuisance tripping on startup inrush.
The 4 A thermal current (Ith) is the continuous current the relay can carry under normal conditions — this is the rating you match to the motor FLA. The 690 V rated value covers most low-voltage motor circuits up to 600 V class. The CLASS 10E trip curve is standard for standard-start induction motors; it allows the motor to accelerate without tripping but still protects against locked-rotor or sustained overload. The S0 frame size is compact: 45 mm wide, 109 mm high, 85 mm deep. It mounts directly onto a contactor (contactor mounting), saving DIN-rail space in a panel. The spring-loaded terminals accept 2× (0.25–1.5 mm²) solid or stranded wire, or a single 10 mm² stranded — enough for the 4 A circuit without needing ferrules for smaller gauges. The auxiliary switch is integrated (design of the auxiliary switch: integrated) and provides a signal contact rated for 4 A at 120 V, 3 A at 230 V, 2 A at 24 V — enough to drive a PLC input or indicator lamp. The note for message "tripped" indicates the auxiliary contact position when the relay has tripped.
This relay is sized for motor control centers and individual motor starters in the SIRIUS system. It clips onto a SIRIUS contactor (contactor mounting) — no separate DIN-rail footprint needed. Vibration resistance is 1–6 Hz at 15 mm amplitude, 6–500 Hz at 20 m/s² for 10 cycles; shock resistance is 15g for 11 ms on the main body, 9g for 11 ms on the signaling contact in tripped position — robust enough for most industrial environments. Storage and transport range is -40 to +80 °C.