🔹 Siemens Thermal Overload Relay – 3UA55002A (3UA Series, Variant A)
The Siemens 3UA55002A 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 operates using a bimetallic thermal sensing system, where excess current heats the bimetal strip, causing it to bend and activate the trip mechanism, disconnecting the motor circuit to prevent damage.
This relay is typically used with Siemens contactors in motor starter assemblies, ensuring reliable and economical protection for industrial motors operating in continuous duty. It helps prevent overheating, winding damage, and unexpected breakdowns due to electrical faults.
The 3UA55002A corresponds to a higher current frame range (typically around 20–32 A setting range), making it suitable for medium-to-heavy duty motors used in industrial automation systems.
• Genuine Siemens 3UA Series thermal overload relay
• Model Number: 3UA55002A
• Bimetallic overload protection system
• Adjustable current setting (approx. 20–32 A range)
• Protection against overload and phase failure
• Trip-free safety mechanism
• Temperature compensated operation for stable performance
• Suitable for three-phase motor protection
• Contactor-mounted compact design
• Industrial-grade reliability and long service life
| Parameter | Specification |
|---|---|
| Product Series | Siemens 3UA Series |
| Model Number | 3UA55002A |
| Product Type | Thermal Overload Relay |
| Protection Type | Overload + Phase Failure Protection |
| Operating Principle | Bimetal Thermal Mechanism |
| Current Range | ~20 – 32 A (typical frame range) |
| Mounting Type | Contactor Mounted / Plug-in |
| Application | Motor Protection |
| Compatible Contactors | Typically Siemens 3TF40 / 3TF41 / 3TF50 series (range dependent) |
| Brand | Siemens |
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