Thermal Overload Relay, SIRIUS 3RU2 Series, Motor Protection Relay, Variant CB0 - 3RU2116-0CB0

Product Description

Siemens 3RU2116-0CB0 Thermal Overload Relay – Compact Motor Protection for Low Current Applications

The Siemens 3RU2116-0CB0 Thermal Overload Relay is part of the trusted SIRIUS 3RU2 Series, engineered to provide reliable overload and phase-failure protection for three-phase motors. With an adjustable current setting range of 0.18A to 0.25A, this relay is ideal for protecting low-current motors used in industrial automation, machine tools, control panels, conveyors, pumps, and HVAC applications. It is designed for direct mounting on Siemens S00 contactors, enabling compact and efficient motor starter assemblies.

The relay utilizes a proven thermal bimetal tripping mechanism that continuously monitors motor current and accurately reflects motor heating characteristics. When an overload condition occurs, the relay trips before excessive heat can damage motor windings or insulation, helping extend motor life and improve system reliability. The inverse-time tripping characteristic ensures dependable protection while minimizing nuisance trips.

Featuring a Class 10 trip characteristic, the 3RU2116-0CB0 is suitable for motors with normal starting conditions. It provides rapid protection against overload conditions while allowing normal motor starting currents to pass without interruption.

The relay offers an adjustable current range of 0.18–0.25A, allowing precise matching to the motor’s full-load current requirements. Accurate adjustment improves protection performance, reduces downtime, and helps optimize motor efficiency.

A key advantage of the Siemens 3RU2116-0CB0 is its integrated phase-failure and phase-asymmetry protection. In the event of phase loss, the relay responds quickly to prevent motor overheating and winding damage, improving safety and operational reliability.

The relay features screw terminal connections for both main and auxiliary circuits, ensuring secure wiring and easy installation. Standard auxiliary contacts include 1 Normally Open (NO) and 1 Normally Closed (NC) contact for signaling, alarm functions, PLC interfacing, and motor control applications.

For operational flexibility, the 3RU2116-0CB0 includes manual and automatic reset functions, a STOP button, TEST function, and switch position indicator, simplifying commissioning, maintenance, and troubleshooting.

Built according to international industrial standards, the relay offers 690V insulation voltage, 6kV impulse withstand voltage, and IP20 protection, making it suitable for demanding industrial environments and long-term operation.