Design and realization of a novel visual educating device for rotating magnetic fields

Principle of rotating magnetic field is very difficult to understand to new learners because the field is in high speed and invisible. In this paper a novel dynamic demonstrating device for rotating magnetic field is designed. With the help of synchro transmitter and phase demodulating technologies, a rotating handle is adopted as speed input to drive the magnetic field rotating at a speed of only several revolutions per second, which enables the operators to observe the relation between synchronous speed of the rotating magnetic field and frequency of stator currents directly and clearly. The device can be used to demonstrate all kinds of powered states of three-phase AC windings, including open circuits of several windings, with or without a neutral line, rotating direction exchanging, and so on, which present the essence and key points of a rotating magnetic field. The device is a good assistant for teaching of some Electrical Engineering courses, such as Electric Machinery and Motors and their Drives.