Basler Electric BE1-50 – High‑Speed Instantaneous Overcurrent Relay

The Basler Electric BE1-50 (style G4EA1RG0N0F) is a solid‑state instantaneous overcurrent relay designed to provide fast, reliable tripping for severe fault conditions. It operates without intentional time delay, making it ideal for protecting generators, transformers, feeders, and busbars from high‑magnitude faults that require immediate clearance.

Design and Operation

The relay continuously monitors phase currents via standard current transformer inputs. When the current exceeds the user‑adjustable pickup setting, the relay trips instantaneously, typically within one cycle (16 ms at 60 Hz). The BE1-50 features a target indicator that latches on trip for fault diagnosis, and a manual reset pushbutton. Its solid‑state design eliminates moving parts, ensuring fast response and long life.

• Current inputs: 1 A or 5 A nominal (field‑selectable)

• Pickup range: 1–40 A (in 0.1 A steps)

• Operating time: < 20 ms for 2× pickup

• Accuracy: ±3% of setting

• Output contacts: 2 Form‑C relays, 5 A at 250 V AC

• Power supply: 120/240 V AC or 125/250 V DC

• LED indicators: power and trip status

• Mounting: standard draw‑out case

• Operating temperature: –20 °C to +65 °C

Application Areas

This relay is commonly deployed as primary protection for feeders, motor branches, and transformer primaries. It is also used as a backup for generator differential protection, clearing severe phase‑to‑phase or phase‑to‑ground faults. Its instantaneous characteristic ensures coordination with downstream time‑overcurrent relays, providing selective tripping.

Installation and Configuration

The BE1-50 mounts in a standard panel cutout with front‑accessible controls. The pickup value is set using a rotary switch, and a test jack allows secondary injection testing. The relay includes a seal‑in feature to maintain trip indication until manually reset.

Reliability and Compliance

Manufactured with high‑grade components and protected against transients, the BE1-50 complies with IEEE C37.90 and IEC 60255 standards. Its robust construction ensures dependable operation in harsh substation environments.

In summary, the Basler Electric BE1‑50 instantaneous overcurrent relay provides ultra‑fast fault detection and tripping, essential for minimising damage to power system equipment.