Otis Elevator Company

Brian J Amend

Richard N Fargo

Michael Garfinkel

James P Towey, Jr

K Narasimha Reddy

Donald F Cominelli

William F Brooks

Magnetizing current generated in a linear induction motor driving elevator car doors in elevator systems is optimized. Magnetizing current level is set low for door operation modes requiring lower levels of thrust, such as hold open and hold closed. Magnetizing current level is increased for modes of door operation requiring greater thrust levels, such as closing or opening. Optimization of magnetizing current in linear induction motors reduces overheating and increases energy efficiency.

Optimization of magnetizing current in linear induction motors

An apparatus for detecting weak beams in an beam detection system includes a plurality of emitters for radiating beams of energy, a plurality of detectors for providing detector signals in response to the beams of energy radiated by said plurality of emitters and means for detecting if the beams radiated by said plurality of emitters are weak. If weak beam is detected, the beam is determined inoperative by the obstruction detection system and is not considered in subsequent obstruction detection.

Weak beam detection

An apparatus for detecting obstructions includes a plurality of emitters for radiating beams of energy, a plurality of detectors for providing detector signals in response to the beams of energy radiated by the plurality of emitters and a controller for determining if the beams of energy are obstructed by analyzing the detector signals and implementing a dynamic detection threshold. The controller generates an average beam strength and current beam strength from which said controller means determines if an obstruction is present by determining if the current beam strength is within a predetermined range of the average beam strength.

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Old Lyme, CT, United States of America

Brian J Amend