Patent ID: 6686761
Filing Date: 2004-02-03
Classification: G01R

Abstract:
A method for examining whether the magnetic property of a rotor is good by measuring the electromotive force (emf) of a motor and determining the quality of the motor rotor from the measured back-emf constant, the method comprising:preparing a standard stator that contains at least a driving coil of one phase and at least an induction coil wound thereon; combining a test rotor with the standard stator and providing at least a driving voltage of one phase to the corresponding driving coil on the standard stator using a driver so as to rotate the test rotor; generating a back-emf signal from the test rotor and outputting the back-emf signal through the induction coil; measuring the rotational speed of the motor; computing the back-emf constant of the motor by dividing the back-emf signal by the rotational speed of the motor; and determining the quality of the test rotor by dividing the back-emf constant of the motor by the winding ratio between the driving coil and the induction coil.