Siemens Industrial Controls 3RB2056-1FW2 Overload Relay

For large-scale motor protection in demanding industrial environments, the Siemens 3RB2056-1FW2 Solid State Overload Relay provides technical precision that traditional thermal units can't match. Engineered for SIRIUS Size S6 contactors, this high-performance monitoring device features a broad 50-200 Amp adjustable range, making it a versatile choice for safeguarding heavy-duty three-phase motors. Unlike bi-metal alternatives, this electronic overload relay utilizes pass-through current transformers (straight-through CTs) for current sensing, effectively reducing heat generation and power loss within the control cabinet. The architecture supports both direct mounting to a contactor and stand-alone installation on a 1000V AC circuit, offering flexibility for retrofits or new panel builds. Designed for Class 10 tripping characteristics, it ensures rapid response to phase failure, unbalance, and sustained overcurrent conditions. For the field technician, the integration of screw terminals on the auxiliary circuit, along with selectable manual or automatic reset modes, streamlines commissioning and minimizes downtime during fault recovery.

• Enhanced Thermal Stability: The solid-state design eliminates the need for external cooling and internal bi-metal heating, improving cabinet longevity.
• Precision Current Adjustment: A wide 50A to 200A range allows for fine-tuning based on the specific motor Full Load Amperage (FLA).
• Universal Compatibility: Specifically optimized for Siemens 3RT105 series contactors but adaptable for stand-alone DIN rail or surface mounting.
• Phase Loss Protection: Integrated monitoring detects phase asymmetry and failure faster than standard thermal relays to prevent motor winding damage.

Can the 3RB2056-1FW2 be used with a 1-Phase load?
No, this specific solid-state model is designed exclusively for 3-phase sinusoidal 50/60 Hz networks. For single-phase AC or DC applications, a thermal relay like the 3RU series is required.

What is the benefit of the straight-through transformer design?
The pass-through design allows primary cables to be routed directly through the relay housing. This reduces the number of electrical connection points, lowering the risk of high-resistance terminations and simplifying high-current wiring.

How do I reset the relay after a trip event?
The unit features a blue reset button that can be configured for Manual or Automatic operation. In automatic mode, the relay typically requires a 3-minute recovery period to ensure the electronics and motor circuit have sufficiently stabilized.

Disclaimer: While we strive for 100% accuracy, product data and specifications are subject to change. Please contact our team to confirm compatibility or technical details before purchasing.