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. 10, 1988
Filed:
Mar. 31, 1987
Edward C Prather, Hendersonville, NC (US);
Westinghouse Electric Corp., Pittsburgh, PA (US);
Abstract
Motor protection relay is taught in which a microprocessor is utilized in conjunction with a reduced voltage motor starter and the electrical motor system which it operates upon to cause the motor to start in stages. The microprocessor-based system infers a start by the presence of a minimal amount of electrical current flowing in the three-phase system which supplies power to the motor starter and thence to the motor. After the start has been inferred, the microprocessor controlled protection device will issue a transition command for the second stage of the start operation where higher voltage is placed across the motor terminals when the in-rush current has fallen to a predetermined programmable value which approximates full load current, for example. An 'incomplete sequence' feedback line is provided which is supplied from the auxiliary contacts of the low voltage starter to the microprocessor.