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:
Nov. 03, 1987
Filed:
May. 30, 1986
Harry C Hopkins, Williamston, NC (US);
Other;
Abstract
A motor drive circuit controlling the period of each cycle of line voltage which is supplied through an electronic switch to a motor winding. The phase difference between the current through and the voltage across the winding is measured and compared to a reference. The duration of the period of a cycle when the switch is closed and supplies power to the motor winding is varied in relation to the phase comparison so as to maintain an optimal phase angle or power factor for the motor. To eliminate misfiring of the switches in a single phase unit, an a.c. coupled power supply is used to power the control circuits and a varistor is located across the line. Also, fuses are used to protect the circuitry. In a three phase circuit, resistive dividers in current and voltage sensing circuits are matched within 1% of each other to provide proper triggering of the switches of each phase with respect to each other.
Data source: USPTO (United States Patent and Trademark Office) public patent records. Weekly synchronization. How IDiyas builds this profile