SIRIUS 3US Thermal Overload Relay for Reliable Motor Overload Protection – 3US5500-2D8K

🔹 Siemens SIRIUS 3US Thermal Overload Relay – 3US5500-2D8K (Motor Protection Relay)

🔹 Product Description

The Siemens 3US5500-2D8K is a thermal overload relay from the SIRIUS 3US series, designed for reliable protection of electric motors in medium-current industrial applications. It safeguards motors from overload, phase failure, and overheating, ensuring stable and safe operation in continuous-duty environments.

This model belongs to the 3US5500 frame range, commonly used in contactor-mounted motor starter systems for industrial machinery such as pumps, compressors, conveyors, HVAC systems, and general automation equipment. It is typically integrated with Siemens contactors for modular motor protection in control panels.

The relay works on a bimetal thermal principle, where motor current flows through heater elements that heat up bimetal strips. When the temperature exceeds the preset threshold for a sustained period, the strip bends and triggers the trip mechanism, disconnecting the motor to prevent damage. This provides inverse-time overload protection, meaning higher overload results in faster tripping.

Based on Siemens SIRIUS design principles, this relay is engineered for accurate current adjustment and phase-loss protection, making it suitable for industrial motor protection in demanding environments.

🔹 Key Features

• Genuine Siemens SIRIUS 3US series thermal overload relay
• Model: 3US5500-2D8K
• Designed for medium-current motor protection applications
• Bimetal thermal overload protection technology
• Protection against overload and phase failure
• Suitable for industrial motor starter systems
• Compatible with Siemens contactor-based assemblies
• Reliable inverse-time tripping mechanism
• Phase-loss sensitivity for enhanced motor safety
• Industrial-grade durability and long service life