Patent ID: 6774664
Filing Date: 2004-08-10
Classification: G01R

Abstract:
Method for automated measurement of the ohmic rotor resistance (Rr) of an asynchronous machine controlled via an inverter while being acted upon by a non-rotating field, the method comprisinga. measuring the ohmic stator resistance (Rs), the leakage inductances (L&sgr;s, L&sgr;r) and the main inductance (Lm) of the asynchronous machine, b. applying a testing signal (Usa) consisting of a predetermined direct signal with a superimposed alternating signal to a phase winding (a) of the asynchronous machine, the frequency of the alternating signal corresponding approximately to a nominal slip frequency (fs) of the asynchronous machine, c. measuring the amplitude and the phase (&phgr;) of the phase signal({overscore (I)}sa) resulting from the testing signal, and d. calculating the ohmic rotor resistance (Rr) from the measured values according to steps a) and c).