UFC921A101 3BHE024855R0101

UFC921A101 3BHE024855R0101 is an ABB Unitrol 5000 Excitation System Control Board (also referred to as ABB 3BHE024855R0101 INT-2 Varnished Control Board, Generator Excitation Regulation Circuit Board), a core control component designed for ABB’s Unitrol 5000 static excitation systems used in synchronous generator voltage and reactive power regulation.

The UFC921A101 3BHE024855R0101 module is a high-performance varnished INT-2 control board developed by ABB, specifically engineered for the Unitrol 5000 self-shunt static excitation system—one of the most widely used excitation systems for synchronous generators. Its primary function is to control the excitation current of the generator through a silicon-controlled rectifier (SCR) bridge, enabling precise regulation of the generator’s terminal voltage and reactive power output to ensure stable grid integration and power generation performance.

Featuring a rugged, varnished circuit board design, the module provides enhanced protection against moisture, dust, and chemical contaminants, making it suitable for harsh industrial environments in power plants and generator facilities. It integrates analog/digital signal processing, communication, and control logic to interface with the excitation transformer, automatic voltage regulator (AVR), SCR bridge, and de-excitation unit of the excitation system. The module also supports seamless integration with ABB AC 800F PLCs and industrial automation systems via Modbus, Profibus, and Profinet protocols, enabling real-time monitoring and control of the excitation system.

Widely applied in power generation (thermal, hydro, gas turbines) and industrial generator systems, the UFC921A101 3BHE024855R0101 plays a critical role in maintaining generator voltage stability, optimizing reactive power control, and ensuring reliable operation of synchronous generators in grid-connected and standalone modes.