ABB 3BHE024855R0101 UFC921A101 Excitation Control Unit Board for Unitrol Excitation System

Description

ABB 3BHE024855R0101 UFC921A101 Excitation Control Unit Board for Unitrol Excitation System

Product Details

The UFC921A101, material number 3BHE024855R0101, is a core control board for ABB Unitrol generator excitation systems. Origin: Switzerland. Lifecycle status: EOL discontinued, no brand‑new OEM supply; market supplies are NOS surplus and fully tested refurbished units for power plant maintenance.

This board executes excitation regulation logic, analog signal sampling, pulse generation for thyristor firing, and serial communication with upper‑level control. It handles generator voltage, current sampling, implements automatic voltage regulation (AVR), manual excitation control, limit protection functions. Powered by rack backplane, operating temperature ‑20℃ ~ +70℃. Conformal‑coated PCB variant available for harsh cabinet environment. Multiple hardware revisions exist; revision must match original unit during replacement. Weight approx 1.25 kg. It is widely deployed on thermal‑power, hydro‑power synchronous generator excitation cabinets.

UFC921A101 3BHE024855R0101

Applications

‑ Thermal‑power plant generator Unitrol excitation system spare‑part replacement ‑ Hydro‑power station synchronous generator excitation control cabinet ‑ Cogeneration plant and industrial backup generator excitation system maintenance ‑ Metallurgy large‑capacity generator set retrofit projects ‑ Power‑plant AVR automatic voltage‑regulation loop hardware ‑ Spare‑inventory for power‑plant electrical maintenance department ‑ Upgrade and component swap for legacy ABB Unitrol excitation racks

Related Series Models (6+)

1. UFC921A102 (3BHE024855R0102)
2. UFC911A101
3. 3BHE025541R0101 UFC092AE01
4. 3BHE032025R0101
5. UNITROL 1000 excitation series accessories
6. 3BHE019719R0101
7. UFC718AE01

Key Features

1. Dedicated main control board for ABB Unitrol excitation system, undertakes AVR automatic voltage‑regulation algorithm execution.
2. Completes generator voltage and current analog sampling, generates SCR thyristor firing pulses for excitation power unit.
3. Integrated multiple protection functions: over‑excitation, under‑excitation, over‑current monitoring and limit logic.
4. Supports auto / manual dual excitation control mode switching for generator‑set commissioning and grid‑parallel operation.
5. Serial communication interface for parameter configuration, fault log upload with host HMI system.
6. Conformal‑coated PCB option, adapts to high‑humidity, dusty power‑plant cabinet environment.
7. Multiple hardware revisions; strict revision verification required before field replacement to avoid incompatibility.
8. Manufactured in Switzerland, CE certified, EOL obsolete, only NOS or fully‑tested refurbished spare‑parts available.

Main Functions

1. Realize generator automatic voltage regulation (AVR), stabilize generator terminal voltage under varying load conditions.
2. Sample generator voltage, current and excitation‑loop analog signals, complete closed‑loop calculation.
3. Output trigger pulses to control thyristor rectifier bridge, adjust excitation current of synchronous generator rotor.
4. Implement excitation‑system limit and protection logic: over‑excitation, under‑excitation, loss‑of‑excitation interlock alarm.
5. Support auto/manual mode switching, convenient for unit commissioning and grid‑connected parallel operation.
6. Store excitation‑system configuration parameters and fault event logs for maintenance traceability.
7. Communicate with upper‑level monitoring system, upload operating status and receive remote parameter modification commands.
8. Serve as core algorithm and pulse‑generation control board inside ABB Unitrol generator excitation cabinet.