Basler BE1‑27 Under Voltage Relay

The Basler BE1‑27 is a solid‑state under voltage relay designed to protect electrical equipment from damaging low voltage conditions. This model, with configuration BE127 A3EC1JA0N5F, provides reliable detection of voltage drops and initiates tripping or alarm signals when the voltage falls below a preset threshold. It is widely used in generator sets, motor control centers, and industrial power distribution systems.

Key Features

The relay features adjustable voltage pickup setpoint and independent time delay. It includes high‑accuracy voltage sensing with hysteresis to prevent chattering. The unit provides both instantaneous and time‑delayed output contacts. Front‑panel LEDs indicate power, voltage status, and trip conditions. The relay is housed in a robust enclosure for panel mounting.

Technical Specifications

Input voltage: 120 or 240 VAC, 50/60 Hz. Voltage pickup range: 80‑120% of nominal (adjustable). Time delay: 0.1‑10 seconds (adjustable). Trip accuracy: ±1% of setpoint. Output contact rating: 5 A at 250 VAC resistive. Operating temperature: -20°C to +55°C. Auxiliary supply: 120/240 VAC or 48/125 VDC.

Operating Principles

The relay continuously monitors the input voltage. When the voltage drops below the pickup setpoint, the timing circuit initiates. If the voltage remains below the threshold for the entire time delay, the output relay is energized. The hysteresis prevents nuisance tripping during momentary fluctuations.

Applications

This relay is used for undervoltage protection of motors, generators, and sensitive electronic loads. It is also employed in automatic transfer schemes and generator starting controls to prevent operation during low voltage conditions.

Installation and Configuration

Mount the relay in a standard panel cutout. Connect the voltage inputs and output circuits. Adjust the pickup setpoint and time delay using front‑panel knobs. A calibration check with a variable voltage source is recommended.

Maintenance and Reliability

Solid‑state design ensures high reliability with minimal maintenance. Periodic testing verifies trip accuracy. Routine inspection of connections is sufficient.

Conclusion

The Basler BE1‑27 under voltage relay offers dependable undervoltage protection with flexible settings, ensuring safe operation of electrical equipment.