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. 11, 1995
Filed:
May. 31, 1994
Tetsuji Sakurai, Tokyo, JP;
Katsuhiko Kaida, Tokyo, JP;
Kabushiki Kaisha Toshiba, Kawasaki, JP;
Abstract
When a sensorless spindle motor having a rotor and a plurality of coils is started, a CPU outputs phase control signals to an excitation phase switching circuit to forcibly rotate the rotor. The CPU detects based on rotor position signals from a rotor position detecting circuit whether or not the rotor is rotated in the forced rotation. As a result, when the rotor is not rotated, the CPU retries the forced rotation. In each retried forced rotation, the CPU decreases the rotational speed of an excitation phase of each coil. The CPU may also execute the forced rotation after the rotor is aligned to an arbitrary position. When the rotor is not rotated in the forced rotation, the CPU retries the forced rotation. In each retried forced rotation, the CPU changes the excitation start phase.