Basler Electric BE3‑47N/27‑3A4N2 Voltage Relay

The Basler Electric BE3‑47N/27‑3A4N2 (part number 9320400101) is a microprocessor‑based voltage relay that combines two independent protection functions: negative‑sequence overvoltage (ANSI 47N) and undervoltage (ANSI 27). This dual‑function relay provides comprehensive voltage protection for motors, generators, and transformers in a single compact unit. Its digital accuracy and programmable settings enable precise coordination with system requirements, making it ideal for modern industrial and utility power systems.

Protection Functions

The negative‑sequence voltage element (47N) monitors voltage imbalance, which can cause rotor heating and motor damage. The pickup and time delay are independently adjustable. The undervoltage element (27) protects against voltage sags that can lead to motor stalling, contactor dropout, or generator instability. Both elements feature inverse‑time or definite‑time characteristics, selectable by the user. The relay also includes a built‑in alarm and trip output for each function.

User Interface and Programming

A front‑panel LCD display shows measured voltages, status, and settings. Four pushbuttons allow navigation and parameter adjustment. The relay stores settings in non‑volatile memory. Communication via RS‑485 Modbus RTU enables remote monitoring and control. LED indicators show the status of each protection element and relay health.

Technical Specifications

Input voltage: 100‑480 VAC, 50/60 Hz, three‑phase. Pickup accuracy: ±1% of setting. Time delay: 0.05‑10 seconds (adjustable). Output contacts: 2 Form C (trip and alarm), rated 5 A at 250 VAC. Power supply: 24‑250 VDC or 120‑240 VAC. Operating temperature: –30°C to +70°C. Enclosure: IP30, panel‑mount. Compliance with IEEE C37.90 and IEC 60255.

Applications

This relay is used in motor control centers, generator protection panels, and transformer monitoring systems. It provides primary protection against voltage unbalance and undervoltage in critical industrial processes. It can also be used as backup protection for larger generator sets.

Installation and Commissioning

Mount the relay in a standard panel cutout. Connect three‑phase voltage inputs and control power. Commissioning involves setting the pickup levels and time delays for both functions, then verifying with a test set. The relay includes a self‑test mode for quick functional checks.

Reliability and Quality

Basler Electric’s BE3‑47N/27‑3A4N2 is built with industrial‑grade components and conformal coating. It undergoes rigorous testing for temperature, humidity, and surge immunity. The relay is backed by Basler’s technical support and warranty.

Conclusion

The Basler Electric BE3‑47N/27‑3A4N2 voltage relay (9320400101) offers versatile, precise voltage protection in a compact design. Its dual functionality and programmable features make it a valuable asset for protecting electrical equipment from voltage‑related faults.