Basler Electric BE3‑25‑1A1N4 Synch Check Relay

The Basler Electric BE3‑25 (part number 9319100100) is a microprocessor‑based synchronism‑check relay designed to ensure safe paralleling of two AC sources. It monitors voltage magnitude, phase angle, and frequency difference between the sources and issues a permissive signal only when all parameters are within preset limits. The relay is suitable for generator paralleling, bus tie transfer, and network interconnection applications.

Measurement and Settings

The BE3‑25 measures both three‑phase voltages and compares them. It offers independently adjustable settings for voltage match (1‑20% of nominal), phase angle (1‑30 degrees), and slip frequency (0.05‑1.0 Hz). A dwell timer (0.1‑10 seconds) ensures stability before allowing closure. The relay also supports live‑line/dead‑line logic for automatic transfer schemes, permitting closure when one side is de‑energized.

User Interface

A front‑panel LCD display shows measured values and settings. Four pushbuttons allow navigation and parameter adjustment. LED indicators show source presence, synchronism status, and relay health. An RS‑232 port enables communication with a PC for configuration and monitoring.

Technical Specifications

Voltage input: 100‑480 VAC, 50/60 Hz. Accuracy: ±1% for voltage, ±0.5 degree for phase. Output contacts: 2 Form C, 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. Meets IEEE C37.90 and IEC 60255.

Applications

Used in utility substations, industrial cogeneration, and marine power systems, the BE3‑25 ensures safe paralleling of generators with the grid or with each other. It is also employed in automatic bus transfer schemes to maintain supply continuity.

Installation and Commissioning

Mount the relay in a standard panel cutout. Connect voltage inputs from both sources. Set the parameters via the front panel or software. Commissioning involves verifying measurement accuracy and testing the permissive output under various conditions.

Reliability and Quality

Built to Basler Electric’s high standards, the BE3‑25 features self‑diagnostics and watchdog timers. Its solid‑state design and non‑volatile memory guarantee long‑term performance.

Conclusion

The Basler Electric BE3‑25‑1A1N4 sync check relay offers advanced, flexible, and reliable synchronism checking for modern power systems. Its precise control and robust construction make it an indispensable tool for safe source paralleling.