A variable-frequency drive integrated within or connected to the elevator door operator that controls door motor speed and torque for smooth precise door motion.
Full Definition
The door inverter (or door drive) is a compact VFD specifically designed for the low-power, high-dynamic door motor application. It receives position and speed references from the door control board, drives the door motor with variable voltage and frequency to execute the programmed velocity profile, and enforces closing force limits by monitoring motor current. Modern door inverters include integral braking resistors, encoder interfaces, and CAN bus communication. They enable soft-start and soft-stop door motion, reducing mechanical wear and improving passenger experience compared to older contactor-switched door motors.
