An elevator system equipped with a regenerative variable-frequency drive that returns braking energy to the building's electrical grid instead of wasting it as heat.
Full Definition
A regenerative drive (also called a regenerative variable-frequency drive or ReVFD) includes a bidirectional power converter that allows the elevator motor to act as a generator during braking phases. In a traction elevator, whenever a laden car descends or an empty car ascends, the motor decelerates by generating electricity rather than using resistor braking. The generated power is fed back into the building's AC supply grid where it can be used by other electrical loads. Regenerative drives typically recover 20–35% of the elevator's energy consumption, significantly reducing net power draw and operating costs. They also eliminate the heat dissipation from braking resistors, reducing machine room cooling loads. Regenerative drives are a key feature of green building elevators and contribute to LEED, BREEAM, and ISO 25745 energy performance targets.
