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:
Nov. 10, 1993
Masayoshi Takahashi, Osaka, JP;
Mita Industrial Co., Ltd., , JP;
Abstract
A motor control device capable of obtaining necessary and sufficient torque produced by a motor irrespective of the rotation speed of the motor and capable of preventing overcurrent from being applied to the motor. Pulses having a predetermined pulse width are generated in the period inversely proportional to the number of revolutions of the motor. A current control signal is made effective in a time period during which the pulses are generated, while being made ineffective to use a predetermined reference signal instead in the remaining time period. The current control signal corresponds to current to be supplied to the motor so as to obtain the necessary torque. The predetermined reference signal corresponds to current less than the current corresponding to the current control signal. The ratio of a time period during which the current control signal is made effective is increased at the time of rotation at high speed, while the ratio of a time period during which the reference signal is used is increased at the time of rotation at low speed. Therefore, sufficient current to obtain the necessary torque is supplied to the motor at the time of rotation at high speed. On the other hand, the overcurrent can be prevented from being applied to the motor at the time of rotation at low speed.