What it is and what it does
The Siemens 3RU2116-1AJ0 is a SIRIUS thermal overload relay in the S00 frame size, Trip Class 10, for standard-duty induction motor starts. It mounts directly onto a contactor (contactor mounting, any position) and uses a thermal bimetallic release that compensates for ambient temperature changes across -40 to +60 °C, so the trip point stays accurate whether the panel is in a heated plant or a cold warehouse. Rated insulation voltage is 690 V, with motor power ratings of 0.55 kW at 400 V and 0.75 kW at 500 V — sized for small three-phase motors in conveyor, fan, or pump duty.
Key ratings and what they mean for fit
Trip Class 10 is for motor starts that clear within 10 seconds. The auxiliary switch is integrated and carries the tripped signal — the Note field reads "for message 'Tripped'" — so it can be wired into a PLC input or a status lamp to indicate the relay has operated. The main current circuit uses ring cable lug connections (M3 screws), and the screwdriver spec is Pozidriv PZ2 with a 5–6 mm shaft diameter — no special tooling needed in the panel shop. Dimensions are 76 mm high × 45 mm wide × 70 mm deep, fitting the S00 footprint.
Compliance and documentation
Substance prohibited as of 10/01/2009. MTTF under high-demand rate is 2,280 years.