🔹 Siemens SIRIUS 3US Thermal Overload Relay – 3US5000-1A8K (Motor Protection Relay)
🔹 Product Description
The Siemens 3US5000-1A8K is a thermal overload relay from the SIRIUS 3US series, designed for reliable protection of low-to-medium current electric motors. It protects motors from overload, phase failure, and excessive heating, ensuring safe operation and preventing motor damage in industrial and commercial applications.
This model is part of the 3US5000 frame range, commonly used in compact motor starter assemblies for pumps, small machinery, HVAC systems, conveyors, and control panels. It is typically mounted with compatible Siemens contactors in modular starter configurations.
The relay operates on a bimetal thermal principle, where motor current generates heat in the heater elements. When the current exceeds the set value for a sustained period, the bimetal strip bends and activates the trip mechanism, disconnecting the motor circuit to prevent overheating.
Based on available Siemens 3US series data, this model belongs to a higher current variant within the 3US family (commonly around 6.3–10 A or similar adjustable class depending on configuration) and includes phase-failure protection, ensuring safer motor operation under abnormal supply conditions.
🔹 Key Features
• Genuine Siemens SIRIUS 3US series thermal overload relay
• Model: 3US5000-1A8K
• Designed for low-to-medium current motor protection
• Bimetal thermal overload protection system
• Protection against overload and phase failure
• Suitable for compact motor starter systems
• Compatible with Siemens contactor-based assemblies
• Reliable inverse-time tripping mechanism
• Phase loss sensitivity for improved motor safety
• Industrial-grade durability and long service life
| Parameter | Specification |
|---|---|
| Product Series | Siemens SIRIUS 3US |
| Model Number | 3US5000-1A8K |
| Product Type | Thermal Overload Relay |
| Protection Type | Overload + Phase Failure Protection |
| Operating Principle | Bimetal Thermal Mechanism |
| Current Range | ~6.3 – 10 A (typical class for 3US5000 variants) |
| Mounting Type | Contactor Mounted |
| Application | Motor Protection / Industrial Control Panels |
| Brand | Siemens |
No reviews yet.