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:
Jun. 07, 1988
Filed:
Jun. 23, 1986
Masashi Yonemoto, Inazawa, JP;
Abstract
An apparatus for controlling an A-C powered induction motor for an elevator cage, said apparatus comprising a rectifier for converting 3-phase A-C power into D-C electric power, an inverter connected to the rectifier for converting the D-C power into A-C power of variable voltage and variable frequency, a current detector connected to detect input current of the inverter, a power detector for detecting power supplied to the inverter based upon an output of the current detector, a control unit for generating a command signal to control the inverter in accordance with slip of the induction motor as determined by the power supplied to the inverter, and a correcting unit operable responsive to the power detected by the power detector for correcting the slip of the motor to maintain the power supplied to the inverter at predetermined values.