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:
Jul. 03, 2001
Filed:
Jun. 24, 1999
Takahito Chinomi, Shiga-ken, JP;
Hideo Matsushiro, Kusatsu, JP;
Toshinari Baba, Otsu, JP;
Takehiko Nitta, Kyoto, JP;
Matsushita Electric Industrial Co., Ltd., Osaka, JP;
Abstract
A fan drive device is not affected by variations in the strength of the fan drive motor rotor magnet or the components of the circuit for detecting fan drive motor induction voltage, or by the capacitance of a high capacitance capacitor in a dc supply circuit, and can therefore detect with good precision and without added components the speed of a high voltage, PWM drive fan drive motor when driven by an external force such as the wind. The fan drive device detects fan drive motor speed using a plurality of signals obtained from Hall ICs disposed in the fan drive motor for detecting the rotor magnet position, and prohibits fan drive motor drive when the fan drive motor speed is detected to exceed a specific threshold value.