This original ABB dedicated power conversion and auxiliary control module is matched for UNITROL excitation system and AC800PEC high-power drive control rack, manufactured in Sweden with full three-proof conformal coating on PCB to resist cabinet internal damp, dust and corrosive gas erosion. It adopts standard plug-in backplane installation structure, serving as onboard DC-DC power supply and auxiliary signal processing unit for the whole control cabinet, converting input DC power into stable multi-path working voltage for core control boards and peripheral I/O modules. Original mass production has been discontinued and supplied solely as aftermarket industrial spare parts for power plant and heavy industry renovation projects.

3BHE is unified fixed part code of ABB’s excitation & medium voltage drive dedicated PCB spare parts series.023681 stands for exclusive internal hardware development serial number defined by ABB R&D department for UCD224 hardware platform.R0103 indicates the third revised official production hardware version with fixed factory internal circuit configuration.UCD224A103 is the standard commercial ordering model corresponding to this part number.

Main input power range DC18V~36V, rated standard input DC24V; main adjustable output voltage 24VDC, rated output current maximum 5A, conversion efficiency up to 94%~95% under rated load. Operating ambient temperature -40℃~+85℃, storage temperature -45℃~+90℃, relative humidity 5%RH~95%RH without condensation. Internal isolation withstand voltage 1200VAC between input and output circuit, cabinet installation protection grade IP20, complies with IEC61000 EMC anti-interference standard and CE, UL industrial certification standards. Net weight approx 0.19kg, overall dimension 76.2mm×45.7mm×30.5mm.

Rear gold-finger connector is inserted into rack backplane bus to complete power output and auxiliary status signal interaction with backplane bus. Front terminal wiring terminals are reserved for external main DC power input and branch power distribution wiring for peripheral modules. Multiple onboard LED indicator lights display input power status, output overload warning and internal fault state for field inspection. No independent external fieldbus communication port is configured, only reserved factory internal debugging test pads on PCB for offline parameter calibration and hardware detection.

Realize high-efficiency DC-DC voltage transformation of cabinet input DC power, supply stable rated working power to main control unit, I/O acquisition boards and auxiliary signal circuits inside excitation or drive cabinet. Built-in overvoltage, overcurrent, short-circuit and overtemperature protection logic to automatically cut off output power when abnormal load occurs for protecting subsequent control components. Real-time collect internal operating status data and upload fault alarm signals to main controller via backplane bus once protection action is triggered. Partial onboard auxiliary signal filtering and anti-interference processing for small-signal loops of adjacent modules is also integrated.

Mainly installed inside UNITROL series excitation control cabinets for synchronous generator units of thermal power plants, hydropower stations and gas-fired power stations. Widely configured in high-power synchronous motor drive control cabinets of petrochemical high-pressure compressors, mine main exhaust fans and cement rotary kiln heavy-duty equipment, matched with AC800PEC distributed automation control rack system.

Cut off the overall cabinet main power supply before disassembly inspection or routine maintenance, keep power cut for over 30 minutes to release residual capacitance energy and avoid static damage to internal power chips. Conduct quarterly maintenance to clean dust on PCB surface and gold-finger contact positions with dry soft brush, regularly check and fasten all external wiring terminal screws to prevent poor contact caused by loose wiring. When system prompts power supply fault or partial module abnormal power-off alarm, check external input circuit and rear rack backplane firstly before module replacement. Unauthorized disassembly of original internal power components and arbitrary circuit modification are strictly forbidden; replace complete new module after permanent internal hardware damage is confirmed by professional testing.