Basler Electric BE1‑59 Over Voltage Relay

The Basler Electric BE1‑59 is a solid‑state overvoltage relay that protects electrical power equipment from sustained overvoltage conditions. It continuously monitors single‑phase or three‑phase AC voltages and operates when the voltage exceeds a preset threshold for a selected time delay. The relay is commonly used on generators, transformers, capacitor banks, and distribution feeders to prevent insulation degradation, core saturation, and equipment damage. Its precise measurement and adjustable settings ensure selective coordination with other protection devices.

Measurement and Settings

The relay measures true RMS voltage and compares it to an adjustable pickup setting, typically from 1 to 300 VAC. The time delay is adjustable from 0.1 to 10 seconds, allowing coordination with downstream devices. A front‑panel potentiometer sets the pickup level, and a separate dial adjusts the time delay. The relay includes a target indicator with manual reset for trip identification, and a test pushbutton for functional verification.

Design and Construction

The BE1‑59 is housed in a rugged metal enclosure suitable for panel mounting. It features solid‑state circuitry with high immunity to transients and harmonics, preventing nuisance tripping. The relay is available with one or two output contacts (Form C) rated 5 A at 250 VAC. An integral power supply accepts a wide range of AC or DC control voltages, simplifying installation in various panels.

Technical Specifications

Input voltage: 1‑300 VAC, 50/60 Hz. Pickup accuracy: ±2% of setting. Time delay accuracy: ±3% or 50 ms. Output contacts: 1 or 2 Form C (depending on model), 5 A at 250 VAC. Power supply: 24‑250 VDC or 120‑240 VAC. Burden:<5 VA. Operating temperature: –20°C to +65°C. Compliance with ANSI/IEEE C37.90 and IEC 60255.

Applications

This relay is used in generator protection to prevent over‑excitation, in transformer protection to avoid core saturation, and in feeder protection to detect voltage regulator failures. It can also be applied in capacitor bank protection to prevent overvoltage damage. The BE1‑59 is often coordinated with undervoltage relays for complete voltage protection.

Installation and Commissioning

Mount the relay in a panel cutout. Connect the voltage sensing leads and control power. Commissioning involves setting the pickup and time delay, then testing with a variable AC source to verify trip accuracy. The relay includes a test jack for secondary injection. Regular calibration is recommended to maintain accuracy.

Reliability and Quality

Basler Electric’s BE1‑59 is built with high‑quality components and conformal coating for environmental resistance. It is factory calibrated and tested for surge, ESD, and temperature extremes. The relay has a long service life and is backed by Basler’s technical support.

Conclusion

The Basler Electric BE1‑59 overvoltage relay is a reliable, accurate, and versatile protection device that ensures the safety and longevity of power system equipment. Its adjustable settings and robust construction make it a trusted choice for engineers worldwide.