🔹 Siemens Thermal Overload Relay – 3UA52002B (3UA Series, Variant B)
The Siemens 3UA52002B is a thermal overload relay from the 3UA Series designed to protect three-phase induction motors from overload, phase failure, and sustained overcurrent conditions. It works on a bimetallic thermal mechanism, where motor current heats a bimetal strip; if the current exceeds the set value for a certain time, the strip bends and trips the relay, disconnecting the motor circuit.
This relay is typically used with Siemens contactors in motor starter assemblies, providing dependable and economical protection for industrial motors. It helps prevent overheating, winding damage, and unexpected motor failure caused by electrical faults.
The 3UA52002B is typically in the 12.5–20 A current setting range, making it suitable for medium-duty industrial motors used in pumps, compressors, conveyors, HVAC systems, and general automation applications.
• Genuine Siemens 3UA Series thermal overload relay
• Model Number: 3UA52002B
• Bimetallic overload protection system
• Adjustable current range (12.5–20 A)
• Protection against overload and phase failure
• Trip-free mechanism for safe operation
• Temperature compensated for stable performance
• Suitable for three-phase motor protection
• Compact contactor-mounted design
• Industrial-grade durability and reliability
| Parameter | Specification |
|---|---|
| Product Series | Siemens 3UA Series |
| Model Number | 3UA52002B |
| Product Type | Thermal Overload Relay |
| Protection Type | Overload + Phase Failure Protection |
| Operating Principle | Bimetal Thermal Mechanism |
| Current Range | 12.5 – 20 A |
| Mounting Type | Contactor Mounted / Plug-in |
| Application | Motor Protection |
| Compatible Contactors | Typically Siemens 3TF32 / 3TF33 / 3TF42 (range dependent) |
| Trip Class | Class 10 |
| Brand | Siemens |
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