Description

The ABB TA25DU3.1 is a thermal overload relay from ABB’s TA-DU series, providing motor overload protection with a current setting range of 2.4–3.1 A. Designed for direct mounting onto compatible ABB A9 to A30 contactors, this relay monitors the current flowing through the motor circuit and initiates a trip if the current exceeds the set value for a time period determined by the thermal model built into the relay. This thermal replica accurately simulates the heating of the motor windings, providing reliable protection against overload conditions that would otherwise lead to premature motor failure through insulation degradation.

The TA25DU3.1 complies with IEC 60947-4-1 and provides Class 10A tripping characteristics, appropriate for standard squirrel cage induction motors. The adjustable current setting dial covers the range from 2.4 to 3.1 A, enabling precise calibration to the motor’s nameplate full-load current. A built-in trip indicator provides local fault indication, and a manual or automatic reset button allows the relay to be reset after a protective operation. Phase failure sensitivity is incorporated as standard, ensuring the relay responds to single-phasing conditions that would cause a conventional three-phase thermal relay to underrespond due to the reduction in average current.

The TA25DU3.1 mounts directly onto compatible ABB A9 to A30 contactors, forming a compact and co-ordinated motor starter assembly. Auxiliary contacts are available to provide trip feedback signals to PLCs, SCADA systems, or remote alarm circuits. The relay is used in motor control panels across a wide range of applications including pump drives, fan starters, conveyor systems, and industrial machinery throughout Ireland and Europe, providing reliable thermal protection for three-phase induction motors operating within the 2.4–3.1 A current range.