Overview
The Siemens 3RB2383-4AA1 is a 3-pole evaluation unit for full motor protection, designed for stand-alone installation across contactor sizes S00 through S12. It offers adjustable trip classes 5, 10, 20, and 30, and uses screw-type terminals for the auxiliary circuit. Rated for a switching current of 630 A, the unit provides bistable (latching) operation, meaning it holds its trip state even after a power loss — useful for fault indication on unattended machinery.
This evaluation unit monitors motor current and trips on overload, short-circuit, or phase imbalance. The adjustable trip class (5, 10, 20, or 30) sets the thermal memory curve — class 10 for standard motor start, class 20 or 30 for high-inertia loads like fans or crushers. The 3-pole design covers three-phase motors up to the 630 A switching current rating.
Applications
The 3RB2383-4AA1 is used in motor control centers, pump panels, conveyor drives, and HVAC equipment where a standalone overload relay with adjustable trip class is needed. Its bistable trip memory makes it suitable for remote or unmanned sites where fault persistence must be visible after a power cycle. Compatible with contactor sizes S00 through S12, it fits into existing Siemens motor starter assemblies or as a direct replacement in retrofit panels.