The Otis Spec 60 was the first generation variable voltage variable frequency (VVVF) elevator system designed by Otis and one of the earliest system using microprocessor based VVVF controllers. It was manufactured in the 1990s by Nippon Otis under a license by Meiden of Japan. The drive is most often configured as a closed loop controller utilising low resolution speed sensors to monitor the speed of the elevator. They were available in 10 different models from 30Amps to 350Amps at 220, 380 or 440VAC.
Main article: List of notable Otis Spec 60 elevator installations