Power frequency magnetic field management using a combination of active and passive shielding technology

Power frequency magnetic fields are difficult and expensive to shield, particularly when the fields originate from sources with complicated field patterns. A method is discussed and test data presented which suggests that carefully combining active and passive shielding techniques can produce results which are importantly superior to either technique when used alone. The results are generally consistent with an analysis which considers sources as a superposition of elementary source fields with different order terms.