SIRIUS solid-state overload relay, size S0, 40 A
The Siemens 3RB3026-1VB0 is a SIRIUS solid-state overload relay in size S0, rated for a thermal current of 40 A and Trip Class 10E. The integrated auxiliary switch provides signaling contacts rated at 2 A at 24 V, 4 A at 120 V, and 3 A at 230 V, among other voltage points. The note on this relay reads "for message 'tripped'" — meaning the auxiliary contact position signals the tripped state, not a pre-trip warning.
Trip Class 10E and thermal current rating
The 40 A thermal current rating (Ith) applies at both 480 V and 600 V rated values, so it handles continuous current up to 40 A in the main circuit without derating for voltage up to 690 V. Per-pole power dissipation is 1 W, which helps when calculating enclosure heat rise.
Size S0 is the compact frame for overload relays up to 40 A. Fastening method is contactor mounting — it clips directly onto the matching SIRIUS contactor, no DIN rail adapter needed. Mounting position is any orientation. The screw terminals accept 1x (0.5 to 4 mm²) solid or 2x (0.5 to 2.5 mm²) stranded per clamp; main circuit terminals accept 2x 10 mm² stranded. Screwdriver spec: Pozidriv PZ2 tip, shaft diameter 5–6 mm. Dimensions: 45 mm wide, 87 mm high, 84 mm deep — fits standard panel layouts.
Storage and transport range is -40 to +80 °C. Shock resistance: 15g for 11 ms on the main body; the signaling contact in tripped position withstands 9g for 11 ms. Vibration resistance per IEC 60068-2-27: 1–6 Hz at 15 mm amplitude, 6–500 Hz at 20 m/s², 10 cycles per axis.