Planetary gear reducers - merely a question of efficiency?

Planetary gear drive technology is wide spread in highly reliable applications from automatic car gears to space shuttle mission. However in the lift business worm gear drives traditionally have a very strong position and due to the highly competitive marketplace up to date technology usually is introduced with delay compared to other industrial fields. This now is expected to change by the requirement for compact drives in machine-roomless lifts. In this paper a technical and commercial comparison of different drive concepts is given, with particular reference to the effects on lift design, energy consumption and control equipment.