What it is and what the ratings mean
The Siemens 3RB1065-2KG0 is an electronic overload relay rated for 200...540 A, Class 20, meaning it provides motor overload protection with a trip curve that allows starting inrush without nuisance tripping — Class 20 is the standard for most general-purpose induction motors on conveyors, pumps, and fans. The 200-540 A range covers large-frame motors typical in heavy rotating equipment; the relay mounts directly on a 3RT106 contactor or can be installed individually with connecting bars included.
Deployment context
This relay is sized for panel integration with a 3RT106 contactor or as a standalone unit. The connecting bars are included, so no extra buswork is needed for the contactor mount. Manual reset means an operator must physically clear the trip — standard for unattended or hazardous-zone machinery where automatic restart is not allowed.