Moeller Z5-70 SK3 3 Pole Thermal Overload Relay

The Moeller Z5-70 SK3 thermal overload relay is a 3-pole protection device designed to guard three-phase motors by interrupting current when excess heat is detected. It offers an adjustable current range of 50–70 A and a 250 A rating, and provides one normally open (1NO) and one normally closed (1NC) auxiliary contact. This configuration is intended for use with Moeller Z5-70 SK3 motor starters in industrial automation, delivering reliable overload protection while enabling basic signaling of a trip condition via the auxiliary contacts. The 3-pole design ensures full phase coverage for standard three-phase circuits, helping prevent motor damage and unplanned downtime. Three-pole overload relays monitor each phase to prevent winding damage, and the auxiliary contacts can be wired to interlock a starter circuit or feed a control input when a trip occurs.