The ABB 1SAZ321201R2003 is a TA75DU‑42M thermal overload relay designed to protect three‑phase motors and electrical equipment from overload and phase fault conditions. This electromechanical device is mounted in series with a contactor and continuously monitors the motor load. When the current exceeds the set range or a phase failure occurs, the relay trips to disconnect the motor, helping prevent damage. It features adjustable current setting, temperature compensation, and both trip and signal contacts for control or indication circuits, and can be configured for manual or automatic reset depending on application needs.