Square D by Schneider Electric variable speed AC drive is a type of adjustable-speed drive used in electro-mechanical drive systems to control AC motor speed and torque by varying motor input frequency and voltage. VFD is designed to make industrial and commercial machines more ...Square D by Schneider Electric variable speed AC drive is a type of adjustable-speed drive used in electro-mechanical drive systems to control AC motor speed and torque by varying motor input frequency and voltage. VFD is designed to make industrial and commercial machines more efficient while at the same time, simplifying its integration into a single control system architecture.