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:
Nov. 03, 2020
Filed:
Oct. 11, 2018
Fanuc Corporation, Yamanashi, JP;
Sou Saito, Yamanashi, JP;
Tsutomu Shikagawa, Yamanashi, JP;
FANUC CORPORATION, Yamanashi, JP;
Abstract
A motor drive device includes an inverter configured to convert a DC voltage to an AC voltage by switching power devices, a current detector configured to detect a current output from the inverter, a current controller configured to generate a voltage command, a control signal generator configured to control switching of the power devices, a dynamic brake circuit provided with relays and configured to short-circuit an output side terminal of the inverter via resistances, a storage configured to store an initial current value and a first threshold value, and a failure determiner configured to compare a current value and an initial current value after a predetermined time has elapsed since detection of the initial current value, and determine presence or absence of a failure based on a result of comparing a change rate of the current value from the initial current value with the first threshold value.