Low magnetic signature motor system
AssigneeQinetiq Limited
InventorsMark Nicholas Keene, Stephen Ralph Takel, Peter George Shaw
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Abstract
A low magnetic signature motor system (1) comprises a plurality of electric motors (2), a first shield (9) and a second shield (13). The electric motors are arranged with their associated magnetic moments (6,7) forming a closed loop such that their net external magnetic field (5) is minimised The first shield comprises a material with a high electrical conductivity and substantially surrounds the electric motors such that the a.c. component of the magnetic field is reduced; and the second shield comprises a material with a high magnetic permeability and substantially surrounds the first shield such that the d.c. magnetic field is reduced.
Claims8
A low magnetic signature motor system, the system comprising a plurality of electric motors, a first shielding means and a second shielding means;
- wherein the electric motors are arranged with their associated magnetic moments forming a closed loop such that their net external magnetic field is minimised;
- wherein the first shielding means comprises a material with a high electrical conductivity and substantially surrounds the electric motors such that the a.c. component of the magnetic field is reduced;
- and wherein the second shielding means comprises a material with a high magnetic permeability and substantially surrounds the first shielding means such that the d.c. magnetic field is reduced.
A system according to any preceding claim, wherein the second shielding means comprises one of mu-metal, iron, steel or nickel.
7 A system according to claim 6, wherein the second shielding means comprises mu-metal.
A low magnetic signature motor system as hereinbefore described with reference to the accompanying drawings.
Dependencies are inferred from the claim text.