The Mitsubishi FR-BU2-H15K is a high-duty braking unit designed as an accessory for Mitsubishi’s FREQROL series of variable frequency drives (VFDs). Its primary function is to manage and dissipate regenerative energy that is produced when a motor decelerates rapidly or when controlling an overhauling load. By channeling this excess energy to an external braking resistor (sold separately), the FR-BU2-H15K prevents the inverter’s DC bus voltage from rising to a fault level. This ensures smooth, reliable operation and protects the drive from overvoltage trips. It is an essential component for demanding applications such as cranes, elevators, winders, and high-inertia conveyors, where precise and powerful braking is critical for safety and performance.