Otis Elevator Company

Richard Markus

Ralph S Stripling

Dietmar Thaler

Stefan Spannhake

Oliver Stoxen

Reinhard Henkel

A method of controlling the drive of conveyor installation which includes a drive motor ( ) and a frequency converter ( ) whose output is adjustable, between a load operation and an idle mode, in the form of an escalator ( ) or a moving sidewalk, where: in the load operation mode drive motor ( ) is supplied with a line voltage at an essentially constant line frequency (f ), and in the idle mode with an output voltage of the frequency converter ( ); the line voltage and the frequency converter's output voltage are compared with respect to frequency and phase position; the frequency converter ( ) is set for an output frequency which has a predetermined spacing (&Dgr;f , &Dgr;f ) from the line frequency (f ); a demand to switch modes is signalled by a conveyance signal generator ( ); and at the point in time (t , t ), after a demand to switch modes has been signalled, when the output frequency of the converter ( ) has reached the predetermined frequency spacing (&Dgr;f , &Dgr;f ) from the line frequency (f ), and a predetermined phase spacing has been achieved between the frequency converter's output voltage and the line frequency (f ), a switch-over signal ( ) is emitted to switch the drive motor ( ) between the frequency converter supply and the line supply.

Process for switching between main supply and a frequency inverter and vice versa for an escalator drive

A control system for a passenger conveyor includes a ready-to-operate mode, a standby speed and a nominal speed. A method to operate the passenger conveyor includes the steps of: transitioning the conveyor from ready-to-operate mode to nominal speed using a frequency converter; switching from frequency converter to line power at nominal speed; switching back to frequency converter if no passengers are present and transitioning from nominal to standby speed; and transitioning from standby speed to ready-to-operate mode if a predetermined amount of time passes without a passenger entering the conveyor.

Growing community of inventors

Minden, Germany

Richard Markus