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:
May. 23, 1978
Filed:
Sep. 27, 1976
Chandler A Johnson, Sussex, WI (US);
General Electric Company, Erie, PA (US);
Abstract
Circuit apparatus for providing a signal indicative of speed and direction of rotation of a d-c machine is provided which utilizes an a-c tachometer output as the speed signal from the bi-directional d-c machine. The circuit apparatus includes means responsive to the armature terminal voltage and armature current to provide a signal proportional to the counter electromotive force generated in the armature. Polarity circuit means responsive to nulls in the armature current and the signal proportional to the counter electromotive force generates a signal which is a function of the polarity of the counter electromotive force. An absolute value circuit means is provided for receiving the output of an a-c tachometer driven by the d-c machine. The absolute value circuit means includes switch means responsive to the polarity signal for generating an output signal having an absolute value proportional to the output of the tachometer and the speed of the d-c machine and a polarity which is a function of the direction of rotation of the d-c machine.