The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Mar. 23, 1993
Filed:
Jun. 28, 1991
Masamoto Mizuno, Inazawa, JP;
Terumi Hirabayashi, Inazawa, JP;
Masanori Tawada, Inazawa, JP;
Toshiyuki Kodera, Inazawa, JP;
Mitsubishi Denki Kabushiki Kaisha, Tokyo, JP;
Abstract
An elevator door control apparatus includes an alternating current motor for opening and closing an elevator door. An inverter for converts a DC voltage from a first DC power supply into an AC voltage and supplies it to the motor. A first switching device for connects and disconnects the inverter and the motor, and a second switching device connects and disconnects a second DC power supply and the motor. A detection device detects at least one of an abnormality of the first DC power supply and an abnormality of the motor. A control device, at normal times supplies an AC voltage from the inverter to the motor by means of the first switching device and cuts off a DC voltage from the second DC power supply to the motor by means of the second switching device. When the detection device detects an abnormality, the control device cuts off an AC voltage from the inverter to the motor by means of the first switching device and supplies a DC voltage from the second DC power supply to the motor by means of the second switching device so as to cause a braking torque to be generated in the motor.