It protects a 3-phase motor by monitoring current through its three main poles and tripping a contactor when the load exceeds the setpoint long enough to risk winding damage. The adjustable current response range is 0.22–0.32 A, and the trip characteristic follows Class 10 — meaning it must trip within 10 seconds at 7.2× the set current, a standard for standard-start induction motors that don't need an extended acceleration curve.
Main and auxiliary circuits both use screw-type terminals; the main terminals accept 2× (0.5–1.5 mm²) solid or stranded, or 2× (0.75–2.5 mm²) finely stranded with ferrule. Torque them to 0.8–1.2 N·m.
The 0.22–0.32 A adjustment range is the critical spec: it matches the full-load current of the motor you're protecting. If the motor nameplate says 0.28 A FLA, this relay covers it. The relay is rated for an operating voltage of 690 V at 50–60 Hz, so it's suited for 400 V and 480 V systems with headroom.