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. 27, 1999
Filed:
Apr. 15, 1997
Matsushita Electric Industrial Co., Ltd., Osaka, JP;
Abstract
A protection apparatus used in a brushless motor is arranged by a brushless motor; a commutation signal detecting unit for detecting a position of a movable member of the brushless motor; a speed detecting unit for detecting a rotation speed of the movable member of the brushless motor, involving a rotation direction thereof, in response to the detection signal outputted from the commutation signal detecting unit; and a drive circuit for producing a commutation signal used to drive the movable member of the brushless motor in response to the detection signal outputted from the commutation signal detecting unit and for driving the brushless motor based upon the commutation signal. The protection apparatus is further constructed of an output voltage instructing unit for supplying to the drive circuit, an output voltage instruction signal for instructing an output voltage of the drive circuit, which constitutes a drive voltage when the brushless motor is driven; a voltage limit level setting unit for setting an upper limit value of the output voltage of the drive circuit; and a voltage limiter unit for limiting the output signal of the output voltage instructing unit based on the setting value of the voltage limit level setting unit to thereby limit an upper limit value of the output voltage of the drive circuit.