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. 29, 1988
Filed:
Jan. 06, 1988
J Michael Liptak, Columbia, SC (US);
Square D Company, Palatine, IL (US);
Abstract
An apparatus for measuring the direction of power flow through conductors connecting a load to a source of alternating electric current, the load being capable of generating electric current, and the source of alternating electric current being capable of accepting power flow from the load. The invention comprises at least one wattmeter connected so that the sum of their outputs is proportional to the power flow through the conductors and the sign of the sum of their outputs is indicative of the direction of the power flow. A detector is provided for detecting the sign of the output of the at least one wattmeter. The detector is capable of generating an indicator signal. The indicator signal has a first value when the power flows from the source of alternating electric current into the load and the indicator signal has a second value when power flows from the load into the source of alternating electric current. The wattmeters have at least one switch having contacts that close in response to application of pulsed voltage to the load. At least one sense electric current substantially proportional to the load current flows through the contacts so that the average current flow, including the sign, through the contacts is proportional to the electric power flowing into or out of the load. Also the wattmeters may have at least one switch which closes in response to pulsed current and have a sense electric current proportional to a load voltage.