Effects of conducting shields on the performance of pulsed rotating machines

Conducting shields are often used in pulsed rotating machines to protect th e surrounding electronic devices and humans from exposure to high oscillati ng magnetic fields, These conducting shields are subjected to rotating magn etic fields due to excitation currents in rotor windings, This induces eddy currents, which reduce the magnitude of the operating component of magneti c fields (radial component in drum machine and axial component in disk mach ine), and thus reduce the mutual inductance bet tween rotor and stator wind ings. The eddy currents also induce drag torques on the rotor windings, whi ch results in a degradation of machine performance. In this paper, both dis k and drum pulsed alternators are investigated by the finite element code E MAP3D, The effects of Conducting shields on drag torques and the operating components of the magnetic held are studied, and the results are presented as functions of the gap between the rotor and the shield.