ABB TF42-4.2 Thermal Overload Relay

ABB TF42-4.2 Thermal Overload Relay is a compact, three-pole motor-protection device designed to guard the main circuit in ABB control gear and three-phase motor applications. It carries a fixed full-load current rating of 4.2 A, making it suitable for protecting small to mid-size motors when paired with ABB contactors in the TF42 family. Each pole presents approximately 102 mΩ of winding resistance and typical heat loss of 1.0–1.8 W, and the relay is specified for use with 480/600 V AC systems, aligning with ABB protection schemes for reliable overload protection in industrial motor circuits. The TF42-4.2 variant is sold under part number 1SAZ721201R1035 and is described as an economical electromechanical protection device for the main circuit. Designed for straightforward integration with ABB protection gear, it provides predictable overload protection for three-phase motors, with installation options that suit standard industrial environments and motor-control panels, and it requires no separate control supply.