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:
Jun. 17, 2003
Filed:
Nov. 19, 2001
Dieter Eckardt, Herzogenaurach, DE;
Siemens Aktiengesellschaft, , DE;
Abstract
The invention relates to a method and an apparatus ( ) for determining an operating state of a motor ( ) which is connected to a rigid network ( ) and has a rotation speed sensor. According to the invention, phase voltages (u , u , u ) of the rigid network ( ) which are applied to the connecting terminals (L , L , L ) of the motor ( ) are used to determine its frequency (f ) and amplitude (U ), a measured shaft rotation speed (n) and a number of pole pairs (p) of the motor ( ) are used to determine the slip (s) of the motor ( ) as a function of the determined network frequency (fn), and the mechanical shaft power (P ) is calculated as a function of this slip (s), of the determined amplitude (U ), of an internal voltage (U ) in the motor ( ) and of motor-specific parameters (X , X , X , R , R , R , &sgr;). A method which is independent of power is thus obtained for determining an operating state of a motor ( ), without any need to detect the actual current value.