TOROIDAL COIL WITHOUT MAGNETIC CORE COMPRISING TWO SUPERPOSED WINDINGS

摘要

The invention concerns a coil comprising an insulating support (1) and a conductor wire (3) coiled on the support of an initial end (1l) to a terminal end (1F) to form a first winding (5) with contiguous turns (5A). The conductor wire is then coiled on the insulating support (1) of the terminal end (1F) towards the initial end (1l) of the support to form a second winding (7) with contiguous turns (7A) superposed on the first winding (5). The second winding (7) is centred relative to the choking coil centre to compensate the large turn formed by the choking coil itself, thereby protecting the choking coil against stray magnetic fields. Advantageously, a second conductor wire (4) is coiled around the support to form a third winding (9) with turns (9A) superposed on the first and second windings, and for injecting a test current to calibrate the choking coil in laboratory or in situ simply and economically.