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:
Jan. 08, 1991
Filed:
Jan. 24, 1990
Matsushita Electric Industrial Co., Ltd., Osaka, JP;
Abstract
In a system for driving a brushless motor having motor drive coils connected to respective drive transistors, voltages induced in the drive coils when the motor is rotating are continuously detected to produce energization switching signals to be applied to the drive transistors, thereby switching over energization of the drive coils, so that the motor can be continuously driven at optimum energization timing regardless of its rotational speed. Further, when a rotational direction command signal is applied to a forward-backward switching circuit to instruct the motor to rotate in the backward rotational direction while the motor is rotating in the forward rotational direction, torque of the opposite direction is produced to change the rotational direction of the motor. Further, separate-excitation timing pulse signals are used to sequentially switch over energization of the motor drive coils when the motor is not rotating or it is rotating at a very low speed, and hence voltages induced in the motor drive coils cannot be detected. As soon as the voltages induced in the drive coils have become able to be detected due to the rotation of the motor, self-excitation timing pulse signals are then used to sequentially switch over energization of the drive coils.