Basler Electric BE1‑24 Volts Per Hertz Relay

The Basler Electric BE1‑24 (style A1E F1J D1S0F) is a solid‑state volts‑per‑hertz (V/Hz) relay designed to protect generators, transformers, and other power system equipment from overexcitation. Overexcitation occurs when the voltage‑to‑frequency ratio exceeds the designed capability of the equipment, typically during overvoltage conditions or underfrequency events. This can cause core saturation, excessive magnetizing current, and thermal damage. The BE1‑24 measures the V/Hz ratio and trips when the ratio exceeds a preset threshold, ensuring safe operation of critical assets.

Operating Principle

The relay continuously monitors the system voltage and frequency, calculating the V/Hz ratio in real time. When the ratio exceeds the adjustable pickup setting (typically 1.05 to 1.25 per unit) for a selected time delay (0.1 to 10 seconds), the relay operates its output contacts. The relay includes a built‑in inverse‑time characteristic option that allows coordination with generator or transformer overexcitation capability curves. A target indicator records trip events for post‑fault analysis.

Key Features

Front‑panel potentiometers allow adjustment of pickup level and time delay. LED indicators show V/Hz status and trip conditions. A test pushbutton enables functional verification. Output contacts: 2 Form C (SPDT) – one for trip and one for alarm – each rated 5 A at 250 VAC. The relay is housed in a rugged metal enclosure suitable for panel mounting and operates from a wide range of DC or AC control voltages.

Technical Specifications

Input voltage: 100‑480 VAC, 50/60 Hz. Pickup range: 1.05‑1.25 per unit (adjustable). Time delay: 0.1‑10 seconds, adjustable. Accuracy: ±2% of setting. Output contacts: 2 SPDT, 5 A at 250 VAC. Power supply: 24‑250 VDC or 120‑240 VAC. Burden:<5 VA. Operating temperature: –20°C to +65°C. Meets ANSI/IEEE C37.90 surge withstand.

Applications

The BE1‑24 is used on large generators, step‑up transformers, and excitation systems. It provides protection against overexcitation during start‑up, load rejection, and system disturbances. It is essential for preventing core saturation and insulation damage in critical power equipment.

Installation and Commissioning

Mount the relay in a standard panel cutout. Connect voltage sensing leads from the generator or transformer terminals. Commissioning involves setting the pickup and time delay values, then testing with a variable voltage and frequency source to verify trip accuracy. The relay includes a built‑in test jack for signal injection.

Reliability and Quality

Basler Electric’s BE1‑24 is built with solid‑state technology and conformal coating for environmental resilience. It is factory calibrated and requires minimal maintenance. The relay has a long service life and proven performance in critical applications.

Conclusion

The Basler Electric BE1‑24 volts‑per‑hertz relay (A1E F1J D1S0F) is a precise, reliable, and easy‑to‑use protection device for overexcitation conditions. Its adjustable settings and robust construction make it an essential component in generator and transformer protection schemes.