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:
Apr. 10, 2018
Filed:
May. 13, 2015
Schweitzer Engineering Laboratories, Inc., Pullman, WA (US);
Subhash C. Patel, West Chester, PA (US);
George E. Alexander, Wallingford, PA (US);
Schweitzer Engineering Laboratories, Inc., Pullman, WA (US);
Abstract
Detection of a locked rotor condition of an electric motor during startup herein uses a virtual speed switch. The methods and systems herein determine whether the motor is in a starting state, and the monitor the motor current to determine if it is greater than a predetermined threshold, and that the motor current decrease exceeds a predetermined threshold after a predetermined amount of time. If the decrease in motor current is not less than a predetermined threshold, then a speed switch bit is set, indicating that the rotor is turning. The methods and systems herein further determine whether a physical speed switch is faulty, and determine a locked rotor condition using the virtual speed switch signal, a physical speed switch signal, and whether the physical speed switch is faulty.