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:
Mar. 13, 2001
Filed:
Oct. 14, 1999
Thord Agne Gustaf Nilson, Tyresö, SE;
Atlas Copco Controls AB, Stockholm, SE;
Abstract
A method for restarting a three-phase synchronous permanent magnet motor in which the rotor is still rotating and in which the motor is connected to a drive unit having a DC-stage with voltage measuring means, a variable voltage and frequency output stage including power switching devices, and a means for determining the current in two of the output phases from the drive unit, wherein the motor with the output stage is momentarily short-circuited, the current magnitudes generated by the motor in the two output phases are measured during the short-circuiting moment, the phase angle generated by the motor during the short-circuiting moment is calculated, the rotor speed is determined, and the drive unit is synchronized with the rotor to enable restarting of the motor.
Data source: USPTO (United States Patent and Trademark Office) public patent records. Weekly synchronization. How IDiyas builds this profile