SHIELDING DEVICE FOR METAL OBJECTS SITUATED IN THE NEIGHBOURHOOD OF A HIGH MAGNETIC FIELD GENERATED BY THE ROTOR OF AN ALTERNATOR WITHOUT STATOR

摘要

The protection device comprises two half cages (13, 14) superposed on each other and surrounding the rotor (8) under test. The half cages together constitute a cage with openings between its bars and provided with water cooling in said bars. The cage ensures that the magnetic field generated by a rotor under test with excitation current is stopped within a distance equivalent to the size of the holes between the cage bars. Induced current heating in the cage is kept under control by water cooling, and metal objects outside the cage are substantially protected from the magnetic field by the cage. Air can pass freely through the cage, and the rotor can be observed without removing the cage.