Join 60,000+ competitive exam aspirants
or with email
Your Cart
SubtotalтВ╣0
TotalтВ╣0
Examoogle тАв User тАв info@examoogle.com тАв EE-2024-8821
Chapter 1 of 12 тАв Page 1 of 248ЁЯФТ Protected PDF тАв Watermarked
Join 60,000+ competitive exam aspirants
Those magnetic materials are best suited for making armature and transform cores which have ...........permeability and ...........hysteresis loss
High, high
High, low
Low, high
Low, low
High, low
Quick Summary: Magnetic materials for cores must have high permeability to allow easy flux concentration and low hysteresis loss to minimize energy dissipation during rapid magnetic field reversals. Materials like Silicon Steel are typically used for this purpose to ensure efficiency in transformers and rotating machines.
Magnetic materials for cores must have high permeability to allow easy flux concentration and low hysteresis loss to minimize energy dissipation during rapid magnetic field reversals. Materials like Silicon Steel are typically used for this purpose to ensure efficiency in transformers and rotating machines.
WhтАЛ=╬╖Bmax1.6тАЛfV тАФ Steinmetz hysteresis loss formula
╬╝rтАЛ=╬╝0тАЛHBтАЛ тАФ Relative permeability definition
The hysteresis loss in a magnetic material is proportional to the area enclosed by the B-H loop. A material with high permeability and low coercivity results in a 'narrow' B-H loop, reducing the energy wasted as heat (WhтАЛ=тИоHdB) per cycle. Consequently, this keeps the machine operating at maximum efficiency by reducing core losses.
High permeability minimizes the magnetizing current requirement.
Low hysteresis loss is achieved by using soft magnetic materials.
Silicon steel is the industrial standard for transformer cores to keep these parameters optimal.
Eddy current losses are further reduced by using laminated cores.
Improved energy efficiency of the electrical machine
Reduction in core temperature rise during operation
High permeability materials often have lower saturation flux density
Increased manufacturing complexity due to lamination requirements
Power and Distribution Transformers
Armature cores of DC machines and Induction motors
The area of the B-H loop is directly proportional to the hysteresis loss in Joules per cycle.
Option A is incorrect because high hysteresis loss leads to excessive heating; Option C and D are incorrect because low permeability would require much larger magnetizing currents to produce the same flux.
B is correct тАФ Magnetic cores must have high permeability for efficient flux paths and low hysteresis loss to minimize thermal waste.
Always remember: 'Soft' magnetic materials (e.g., Silicon Steel) are for cores (High ╬╝, Low loss), while 'Hard' magnetic materials (e.g., Alnico) are for permanent magnets (High coercivity).