The Application Of Eddy Current Testing Of The Motor Core Production Process

The core is the most important part in the motor and its quality will influence the whole performance of the motor. The key to improve the quality of the motor is to control the quality of the core strictly. This includes many kinds of ways, such as design, manufacture, procedure.This paper focuses on the application of nondestructive detection in the motor core manufacture, especially the eddy current detection. Aims at silicon steel sheet testing, measures the characteristic with accuracy in order to improve the efficiency and quality of the core product. Two parts are presented, silicon steel sheet thickness measuring with double eddy-current sensors, and silicon steel sheet magnetic characteristic measurement. The first one can be used in motor core height control, the other can be used in sheet testing.The paper synoptically and comprehensively introduces eddy current theory, equivalent circuit, excitation coils, test circuit and application of the eddy-current sensors. A feasible solution of motor core height control based on silicon steel sheet thickness measuring with double eddy-current sensors is presented. Basic theory of the Least Squares Method is recommended. Various fitting methodologies are applied to achieve a better description of the system output characteristic. The method is proved to be a practical way of implementation with expected precision. A new type device is presented to measurement of the magnetic properties of the single sheet, after a detailed account of the parameter of magnetic characteristic and relevant measurement. It is produced to change the traditional measurement of single sheet testing. The design principle and the parameter analysis of the device has be given, accordingly the equations is presented and proved.