Identification of laminated core and winding's physical parameters by stator's modal testings

An accurate prediction of modal characteristics of motor stator is essential in order to design a low vibration motor and to operate it quietly. However, it is difficult to get the physical parameters of laminated core and windings, such as Young's modulus. In this paper, a method to identify the physical parameters of laminated core and windings is proposed based on the modal testing of the motor stators with different conditions. It is shown that the stator windings have a significant effect on modal frequencies of motor stator and cannot be simply treated as an additional mass. In addition, it is found that the generally accepted value of Young's modulus is not valid for a motor with laminations and windings. Comparing the results of 3-D finite element analysis and experimental measurements, the equivalent Young's modulus of the isotropy laminated stator core and the windings are obtained.