Thermal overload relays, For contactor mounting - Class 10 - Screw Terminals - 3MU7110-0BA0

Product Description

Siemens 3MU7110-0BA0 Thermal Overload Relay – Class 10 Protection for Low Current Motors

The Siemens 3MU7110-0BA0 Thermal Overload Relay is a compact and highly reliable motor protection device from the SINOVA 3MU7 Series, specifically engineered to protect low-current three-phase motors against overload and phase-failure conditions. With an adjustable current setting range of 0.16A to 0.25A and a Class 10 tripping characteristic, this thermal overload relay provides dependable motor protection for industrial control systems, automation equipment, small motors, and machine-building applications. It is designed for direct mounting on Siemens 3MT7 contactors (Size 0, Size 1, and Size 2), creating a compact and efficient motor starter assembly.

The relay operates using a proven thermal bimetal mechanism that continuously monitors motor current and accurately reflects motor heating characteristics. When sustained overload conditions occur, the relay trips before excessive heat can damage motor windings or insulation. This inverse-time protection principle helps maximize motor life, reduce maintenance costs, and improve overall system reliability.

Featuring a Class 10 trip characteristic, the 3MU7110-0BA0 is ideal for motors operating under normal starting conditions. It allows standard motor startup currents while providing rapid response to overload conditions. This makes it suitable for small pumps, fans, conveyors, instrumentation systems, control panels, OEM machinery, and industrial automation applications.

The adjustable 0.16A to 0.25A current range enables precise matching to the motor's full-load current requirements. The relay has a rated operational current (Ie) of 0.25A, ensuring accurate protection for sensitive low-current motors and control applications.

A key safety feature of the Siemens 3MU7110-0BA0 Thermal Overload Relay is its integrated phase-failure sensitivity. In the event of a phase loss, the relay accelerates tripping to reduce motor heating and prevent winding damage. This advanced protection significantly enhances operational safety and motor reliability in industrial environments.

Designed for seamless integration with Siemens 3MT7 contactors, the relay features durable screw terminal connections for both the main and auxiliary circuits. These terminals ensure secure wiring, simplified installation, and reliable long-term performance. The relay also supports both manual and automatic reset functions, allowing users to choose the most suitable reset method for their application.

The relay incorporates 1 Normally Open (NO) and 1 Normally Closed (NC) auxiliary contacts for overload trip indication, alarm signaling, PLC interfacing, and motor control circuits. These contacts improve system monitoring and simplify integration into industrial control panels.

Built according to IEC 60947-4-1 standards, the 3MU7110-0BA0 offers 690V insulation voltage, 6kV impulse withstand voltage, IP20 front protection, and dependable operation in demanding industrial environments. It is widely used in manufacturing plants, machine-building projects, HVAC systems, water treatment facilities, and industrial automation installations requiring precise motor protection.