🔹 Siemens SIRIUS Thermistor Motor Protection Relay – 3UW5102-1K (Temperature Monitoring Relay)
🔹 Product Description
The Siemens 3UW5102-1K is a thermistor motor protection relay (PTC-based temperature monitoring device) from the Siemens SIRIUS protection system, designed for direct motor temperature monitoring and advanced thermal protection.
Unlike standard thermal overload relays (which respond to current), this relay works with PTC thermistors installed directly inside motor windings, allowing it to detect actual motor temperature in real time. This ensures high-precision protection against overheating, especially in conditions where current-based protection alone is not sufficient.
It is widely used in industrial motors, compressors, pumps, HVAC systems, conveyors, and frequency inverter-driven motors, where overheating can occur due to low speed operation, frequent start/stop cycles, or poor cooling conditions.
The relay continuously monitors the resistance of PTC sensors embedded in the motor windings. When the temperature exceeds the rated threshold, the resistance increases sharply and the relay triggers a trip signal, disconnecting the motor or activating an alarm circuit.
This makes it suitable for critical motor safety applications where early detection of thermal stress is required.
🔹 Key Features
• Genuine Siemens SIRIUS thermistor motor protection relay
• Model: 3UW5102-1K
• Works with PTC thermistors embedded in motor windings
• Direct temperature-based motor protection (not current-based)
• Fast response to overheating conditions
• Suitable for inverter-driven and heavy-duty motors
• Adjustable sensitivity depending on sensor configuration
• Reliable protection during overload, low-speed operation, and poor cooling
• High safety reliability for industrial motor systems
• Compact DIN rail mounting design (SIRIUS control panel compatible)
| Parameter | Specification |
|---|---|
| Product Series | Siemens SIRIUS 3UW |
| Model Number | 3UW5102-1K |
| Product Type | Thermistor Motor Protection Relay |
| Protection Method | PTC temperature sensing |
| Application | Motor winding temperature monitoring |
| Sensor Type | PTC thermistors (DIN 44081 / 44082 compatible) |
| Function | Overtemperature protection + alarm/trip output |
| Mounting Type | DIN rail (control panel installation) |
| Use Case | Motors, compressors, pumps, HVAC, drives |
| Brand | Siemens |
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