Heavy-Duty Motor Braking Solution

The Fuji BU220-4E Dynamic Braking Unit Kit is a crucial external component for high-capacity Fuji 400V Variable Frequency Drives (VFDs). This unit, often replacing the older BU220-4C, manages and dissipates the large amounts of regenerative energy produced by 200kW to 220 kW AC motors during rapid deceleration, ensuring controlled stops and protecting the VFD from dangerous overvoltage faults.

The BU220-4E is the main switching component and must be combined with a correctly-sized external Braking Resistor (DB) for proper operation.

Key Features

High Power Capacity: Rated for large motors up to 220 kW (~300 HP) in the 400V class.
VFD Protection: Prevents DC bus overvoltage trips during rapid braking or high-inertia load stops.
Direct Replacement: Compatible with most Fuji FRENIC-MEGA, FRENIC-ACE, and other 400V VFD series.
Robust Design: Built for industrial environments, rated to activate at approximately 740V DC.

Technical Specifications & Resistor Pairing

The BU220-4E unit is the same, but the required resistor is rated for different power dissipation (wattage) depending on the drive's duty cycle. The nominal resistance value is the same for both applications but the Resistor Model differs due to wattage/size.

Application (Motor Power)	-	BU Unit Model	Required Resistor Model	Resistance Value (Ohms)
kW	-	BU220-4E
kW	-	BU220-4E

Always verify the specific resistor Wattage (W) with the drive selection guide to match your required duty cycle.

Outline Dimensions (BU Unit Only)

Verify clearances for your control panel using the nominal dimensions below (all measurements in millimeters and kilograms).

Component	Width (mm)	Height (mm)	Depth (mm)	Weight (kg)
Braking Unit (BU220-4E)	450	254	160	12.0
-	-

Downloads

Braking Unit Instruction Manual
Braking Resistor Selection Guide

Engineering Tools

Access our dynamic braking and VFD application calculators.

Fuji BU220-4E Dynamic Braking Unit Kit (160kW to 220kW, 400V Class)

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