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Relevance. Rating Newest Oldest. Best Answer: In a generator, residual magnetism, also known as 'remanence' or remanent flux, is due to the hysteresis of the magnetic material in the core. When the current is removed, the magnetic flux often remains at some non-zero value. This is a characteristic phenomenon of ferromagnetic materials.
Inside these motors, permanent magnets bonded to a flux-return ring replace the stator field windings found in shunt motors. A wound armature and mechanical brush commutation system complete the motor. The permanent magnets supply the surrounding field flux, eliminating the need for external field current. This design yields a smaller, lighter, and energy efficient motor. Unlike a shunt wound dc motor, a PM motor is free of interaction between the permanent magnet field and the armature demagnetizing cross field. Shunt wound DC motors experience significant interaction between the armature and the stator. The statorâs low reluctance (high permeability) iron core ultimately weakens the field as the load increases.