FUJI EP Series Drive Boards EP-3965A-C2

Technical Dossier

Product Details And Specifications

FUJI EP Series Technical Notes

The FUJI EP Series represents a core family of power drive boards and control sub-assemblies deployed across heavy industrial sectors globally, including petrochemical refineries, nuclear power auxiliary systems, steel rolling mills, and large-scale chemical processing plants. Manufactured by Fuji Electric Co., Ltd. (Japan), EP Series boards serve as functional sub-components within FUJI FRENIC and G-series variable frequency drive (VFD) platforms. Their role spans gate drive signal conditioning, DC bus voltage regulation, power transistor protection, and feedback interface between the control card and the IGBT/IPM power stack. The EP-3965A-C2 specifically functions as a power drive board within mid-range FUJI inverter assemblies, providing isolated gate drive outputs and fault detection logic for the main switching devices.

Installed base data indicates EP Series boards remain active in facilities commissioned between the late 1990s and mid-2010s. Given the 15–25 year operational lifespan typical of heavy industrial drive systems, demand for EP Series spare parts remains structurally sustained even as the series approaches end-of-production status.

The Evolution of EP Series Architecture

The FUJI EP Series evolved in parallel with the FRENIC5000 G7/P7 and FRENIC-Multi drive platforms. Early-generation EP boards (circa 1998–2004) used through-hole component construction with discrete optocoupler arrays for gate isolation. Mid-generation variants (2004–2010) transitioned to surface-mount technology (SMT), integrating hybrid gate driver ICs and onboard current sensing resistors. Late-generation EP boards introduced enhanced EMC filtering and compatibility with IGBT modules rated at higher switching frequencies (up to 15 kHz carrier).

Compatibility across sub-generations is not guaranteed. Boards are keyed to specific drive frame sizes and IGBT module types. Substitution requires verification of: connector pinout revision, gate resistor values, DC bus voltage rating (typically 400 V or 690 V class), and firmware-dependent fault threshold calibration. Cross-referencing the drive's nameplate data against the EP board part number suffix (e.g., -C2, -C3) is mandatory before replacement.

EP Series Full Catalog & Functionalities (SKU List)

The following SKUs represent verified EP Series power drive and control board part numbers associated with FUJI Electric inverter platforms. Each entry reflects a distinct functional role within the drive assembly.

EP-3965A-C2: Power drive board for mid-frame FUJI inverter; isolated gate drive outputs, IGBT fault detection.
EP-3964A: Gate drive interface board; compatible with 400 V class FRENIC5000 G7 series.
EP-3966A: High-voltage drive board variant; rated for 690 V class applications in heavy industrial frames.
EP-3967A: Dual-channel gate drive board; used in parallel IGBT configurations for high-current output stages.
EP-3968A: Power supply sub-board; generates isolated auxiliary voltages for gate drive and control logic.
EP-3970A: Current feedback board; interfaces Hall-effect sensors with the main control card.
EP-3971A: Snubber and protection board; integrates RC snubber networks and overvoltage clamp circuits.
EP-3972A: Fan control and thermal management board; monitors heatsink NTC thermistors and controls cooling fans.
EP-3973A: Communication interface sub-board; supports RS-485 and early PROFIBUS-DP physical layer connections.
EP-3974A: Analog I/O expansion board; provides additional 0–10 V and 4–20 mA signal conditioning channels.
EP-3975A: Digital I/O interface board; 16-point optocoupler-isolated DI/DO for external interlock wiring.
EP-3976A: Brake chopper drive board; controls dynamic braking IGBT and monitors braking resistor temperature.
EP-3977A: Rectifier gate drive board; used in active front-end (AFE) regenerative drive configurations.
EP-3978A: Encoder feedback interface board; supports incremental encoders up to 1024 PPR for closed-loop vector control.
EP-3979A: Keypad and display interface board; connects operator panel to main control logic via flat-flex cable.
EP-3980A: EMC filter interface board; integrates common-mode choke connections and Y-capacitor switching for compliance modes.