Otis Elevator Company

Dietrich E Herrmann

Rido Busse

Willy Adrian

Detlev Abraham

Escalator handrail housing

Pair of escalator control boxes

A variable-frequency, variable-voltage (VVVF) converter is interposed in the line between an AC source and an asynchronous escalator motor. Current to the motor is sensed to determine load in conjunction with a passenger detector and load simulating electronic system and the frequency and voltage of the converter are automatically adjusted in response thereto to control escalator speed. The system includes a converter to supply the asynchronous drive motor of the escalator with variable frequency and an appropriate control circuit for manual or automatic operation of the escalator at different speeds, which is equivalent to different motor frequencies.

Growing community of inventors

Vechelde, Germany

Dietrich E Herrmann