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. 25, 1985
Filed:
Feb. 14, 1984
Masayuki Katto, Aichi, JP;
Mitsubishi Denki Kabushiki Kaisha, Tokyo, JP;
Abstract
An inverter control apparatus comprises a first current level setting unit 5 which sets a protection level for switching elements included in an inverter 1, and a second current level setting unit 7 which sets a current level that prevents a stall torque/slip point from being exceeded and which is determined in association with the load characteristic of an induction motor and the voltage/frequency ratio being delivered by the inverter. The smaller of the two current levels is selected to control the frequency to lower or stop its rise to prevent the slip frequency from being exceeded. Thus, stable operation without stalling or damage to the inverter elements is achieved regardless of the voltage/frequency ratio set to drive the motor or the particular induction motor used.