🔹 Siemens SIRIUS Thermistor Motor Protection Relay – 3UW5102-1A (Motor Temperature Monitoring Relay)
🔹 Product Description
The Siemens 3UW5102-1A is a thermistor motor protection relay from the Siemens SIRIUS protection system, designed for direct motor temperature monitoring using PTC sensors. It provides highly reliable protection against motor overheating by continuously measuring the actual winding temperature, rather than relying on current alone.
This relay is used in applications where motors are exposed to high thermal stress, variable speed operation, frequent start/stop cycles, or poor cooling conditions. It works with PTC thermistors embedded inside the motor windings, ensuring early detection of abnormal temperature rise and preventing insulation damage or motor burnout.
The device continuously monitors the resistance of the PTC sensors. When the motor temperature exceeds the safe limit, the resistance increases sharply and the relay triggers a trip or alarm output, disconnecting or protecting the motor circuit.
It is widely used in industrial automation systems, compressors, pumps, HVAC systems, conveyors, and inverter-driven motors, where precise thermal protection is required.
According to Siemens SIRIUS 3UW/3RN thermistor protection principles, this type of relay provides direct temperature-based protection (IEC 60947-8 compliant concept), making it more accurate than traditional thermal overload relays in critical applications.
🔹 Key Features
• Genuine Siemens SIRIUS thermistor motor protection relay
• Model: 3UW5102-1A
• 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
• Provides alarm and/or trip output on overtemperature
• Detects motor winding temperature rise in real time
• Reliable protection under low-speed and poor cooling conditions
• Compact DIN rail mounting for control panels
| Parameter | Specification |
|---|---|
| Product Series | Siemens SIRIUS 3UW |
| Model Number | 3UW5102-1A |
| Product Type | Thermistor Motor Protection Relay |
| Protection Method | PTC thermistor-based temperature monitoring |
| Sensor Type | PTC thermistors (motor winding embedded) |
| Function | Overtemperature protection (alarm/trip) |
| Application | Motor winding temperature monitoring |
| Suitable For | Pumps, compressors, HVAC, VFD motors |
| Mounting Type | DIN rail (panel installation) |
| Brand | Siemens |
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