Basler Electric BE1-851H5B3S0N Overcurrent Relay

Basler Electric BE1-851H5B3S0N Overcurrent Relay is a three‑phase, microprocessor‑based protection relay in the BE1 family that provides time and instantaneous overcurrent protection for feeders, transformers, motors, and generators. This variant uses 5 A current transformers and is powered from 24 VDC, aligning with the H5B3S0N style configuration. The relay implements standard BE1 protection elements, including time overcurrent blocks (51P, 51N, 51Q) and an instantaneous element (50), with multiple signaling outputs (OUT1–OUT5 are normally open, and OUTA can be Form A or B depending on style) to drive trips and alarms. The S0N suffix indicates an S1‑type case with an alarm output and ASCII protocol communication via RS‑485, enabling remote monitoring while the BE1‑851 front‑panel interface supports local setup and status checks. Typical applications include protecting feeders and transformer banks in substations, safeguarding generator circuits, and coordinating motor feeder protection where fast response and configurable signaling are required. This model is designed for retrofit and upgrade scenarios, offering a compact, programmable alternative to electromechanical relays while preserving familiar protection logic and flexible communication options.