Basler Electric BE1-50/51B-235 Overcurrent Relay
The Basler Electric BE1-50/51B-235 is a solid-state overcurrent relay that provides both instantaneous (50) and time-delayed (51) phase overcurrent protection. It is designed for feeder, motor, and generator protection applications where fast fault clearing and selective coordination are required. The relay features a wide range of pickup settings, multiple time-current characteristic curves, and a compact panel-mount design.
Key Features
Combined instantaneous and time overcurrent elements
Adjustable instantaneous pickup from 2 to 80 A (for 5 A CT secondary)
Adjustable time overcurrent pickup from 0.5 to 20 A
Selectable inverse, very inverse, and extremely inverse time curves
Time dial adjustable for coordination
High-accuracy current measurement with thermal compensation
Output contacts for trip and alarm
LED indicators for pickup and trip
Self-test and calibration test points
Technical Specifications
The relay accepts 5 A or 1 A CT secondary inputs, 50/60 Hz. Instantaneous pickup accuracy is ±5 percent. Time overcurrent pickup accuracy is ±3 percent. Time dial settings range from 0.1 to 10. Auxiliary power is 120/240 VAC or 24 to 125 VDC. Operating temperature is -20 to +65 degrees Celsius. The relay meets ANSI C37.90 and IEC 60255 standards.
Protection Functions
The instantaneous element provides high-speed tripping for severe faults near the relay location. The time-delayed element provides backup protection with coordination capability for downstream devices. The inverse-time characteristics ensure proper grading with fuses and other relays.
Installation and Configuration
Panel mounting with rear terminals. Configuration involves setting the pickup values, time dial, and curve selection using DIP switches and potentiometers. The relay includes a target indicator that locks on trip to assist in fault analysis.
Applications
Widely used in industrial distribution feeders, generator backup protection, motor protection, and transformer protection. It is also applied in marine and offshore systems where overcurrent protection is required.
Reliability
Proven solid-state design with high surge withstand capability. The relay is manufactured under ISO 9001 and has type approvals for industrial environments.
Conclusion
Basler Electric BE1-50/51B-235 overcurrent relay delivers reliable, selectable, and accurate overcurrent protection with both instantaneous and time-delayed elements. Its flexibility and ruggedness make it a preferred choice for power system protection.
