OILWELL CASING ELECTRICAL POWER PICK-OFF POINTS

摘要

A power supply apparatus is provided for supplying power and communications within a first piping structure. An external power transfer device (42) is positioned around the first piping structure (24) and is magnetically couple d to an internal power transfer device (44). The internal power transfer devic e (44) is positioned around a second piping structure (26) disposed within the first piping structure (24). A main surface current flowing on the first piping structure (24) induces a first surface current within the external power transfer device (42). The first surface current causes a second surfac e current to be induced within the internal power transfer device (44).