Content last revised on August 28, 2026
Fuji Electric 6RI75G-120 Three-Phase Diode Bridge Rectifier Module
The Fuji Electric 6RI75G-120 delivers resilient three-phase rectification, combining glass-passivated diode chips with high electrical isolation to protect industrial power conversion stages against line surges and harsh ambient conditions.
Top Specs: 1200V VRRM | 75A IO (at TC = 93°C) | 2500V AC Isolation Voltage (1 min).
Key Benefits: Glass-passivated passivation ensures superior moisture resistance; electrically isolated baseplate simplifies multi-module heatsink mounting.
How does the 6RI75G-120 handle input line fluctuations in 400V–480V industrial networks? Its 1200V repetitive peak reverse voltage rating provides a 2.5x voltage headroom, suppressing standard utility transients without premature avalanche breakdown. For 400V AC industrial motor drives requiring reliable input rectification, this 1200V 75A diode module represents the best fit solution.
Key Parameter Overview
Functional Grouping of Maximum Ratings and Electrical Characteristics
| Functional Category | Parameter | Symbol | Test Conditions | Ratings / Value | Unit |
|---|---|---|---|---|---|
| Voltage & Current Limits | Repetitive Peak Reverse Voltage | VRRM | Tj = -40°C to +150°C | 1200 | V |
| Non-Repetitive Peak Reverse Voltage | VRSM | Sine wave 10ms | 1300 | V | |
| Average Output Rectified Current | IO | 3-Phase full wave, 50/60Hz, TC = 93°C | 75 | A | |
| Surge Forward Current | IFSM | 10ms half-sine, rated load initial condition | 750 | A | |
| Electrical & Conduction | Forward Voltage Drop | VFM | IFM = 75A, Tj = 25°C | 1.25 (max) | V |
| Reverse Leakage Current | IRRM | VR = VRRM, Tj = 150°C | 10 (max) | mA | |
| Thermal & Isolation | Thermal Resistance (Junction-to-Case) | Rth(j-c) | Per diode chip, DC operation | 0.38 | °C/W |
| Operating Junction Temperature | Tj | Continuous operation | -40 to +150 | °C | |
| Dielectric Isolation Voltage | Visol | AC 1 min, between terminals and baseplate | 2500 | V |
Download the 6RI75G-120 datasheet for detailed specifications and performance curves.
Application Scenarios & Value
Front-End Rectification in Heavy-Duty Power Conversion
In three-phase industrial equipment, the front-end rectifier module acts as the electrical breakwater, absorbing aggressive grid transients while maintaining a steady DC link for downstream switching stages. Engineers designing front-end rectification for Variable Frequency Drives (VFDs), UPS (Uninterruptible Power Supply) units, and industrial battery chargers frequently encounter high thermal stress caused by sudden load cycling.
The Fuji Electric 6RI75G-120 features an integrated six-diode bridge configuration housed in a compact insulated module. Its 75A continuous output rating at a case temperature of 93°C ensures that industrial motor drives running from 380V–480V three-phase lines can supply heavy torque demands without exceeding internal junction limits.
When starting large inductive loads such as conveyor belts or industrial compressors, high inrush charging currents flow into the DC bus filter capacitors. The 6RI75G-120 addresses this challenge with a surge current rating (IFSM) of 750A (10ms half-sine). This robust withstand capability eliminates the risk of diode rupture during initial soft-start resistor bypass operations.
For systems operating under higher continuous current loads, the related 6RI100E-080 provides an increased current rating of 100A, while the SKKD100/16 offers alternative module packaging for modular rectifier assemblies.
Technical & Design Deep Dive
Glass Passivation and Thermal Interface Dynamics
The longevity of a rectifier in demanding environments depends heavily on surface stabilization of the semiconductor die. The Fuji Electric 6RI75G-120 employs a proprietary zinc-oxide glass-passivation process on each diode chip. Much like an impenetrable ceramic shield protecting exposed metallic structures against oxidation, this glass barrier hermetically seals the P-N junction against moisture, chemical vapors, and ionic contaminants found in industrial plants.
Thermal management is supported by a copper baseplate that maintains an electrical isolation rating of 2500V AC. The internal junction-to-case thermal resistance (Rth(j-c)) is rated at 0.38°C/W per element. By isolating the internal circuit from the baseplate, system designers can mount multiple 6RI75G-120 units or adjacent inverter blocks on a single common heatsink. This significantly reduces assembly volume and overall enclosure footprints.
To ensure system integrity, designers should balance thermal interface resistance through proper thermal grease application, as outlined in our guide on why thermal resistance matters in power module thermal design. For matching downstream inverter switches, explore our technical breakdown of IGBT module operation and system topologies.
What is the primary advantage of glass passivation in the 6RI75G-120? Superior junction stability and ultra-low leakage current under high operating temperatures.
Why is baseplate isolation essential for three-phase bridges? It enables direct shared heatsink mounting without individual insulating mica pads.
Frequently Asked Questions
Engineering Inquiries & Selection Criteria
How does the 1200V VRRM rating of the 6RI75G-120 ensure reliability in 400V/480V three-phase systems?
A standard 400V AC three-phase supply generates a nominal DC bus voltage of approximately 565V, with peak line voltages reaching around 680V during allowable +10% grid tolerances. The 1200V VRRM rating provides more than 500V of surge margin, ensuring that standard commutation notches, inductive kickback, and utility fluctuations do not drive the diode elements into destructive breakdown.
What mounting and heatsink precautions are recommended for the 6RI75G-120?
To maintain the specified Rth(j-c) of 0.38°C/W, the module baseplate should be mounted on a smooth heatsink surface (flatness within 50 µm) with a thin, uniform layer of thermal interface material (TIM). Tighten the M5 mounting screws evenly in alternating sequence to a recommended torque of 3.0 N·m to avoid mechanical stress on the internal ceramic substrate.
For inventory availability, technical specifications, and bulk inquiries on the Fuji Electric 6RI75G-120, submit your request to our technical sales team for immediate dispatch and volume quotation.
