Principle of Water Content Test of Insulating Oil
Collecting Oil Sample from Oil Immersed Electrical Equipment
Causes of Insulating Oil Deterioration
Acidity Test of Transformer Insulating Oil
Magnetic FieldClosely Related Articles
Electrical Engineering Materials
What is an Atom?
Atomic Energy Levels
Classification of Engineering Materials
Classification of Electrical Engineering Materials
Electron Configuration of Atom
Physical Properties of Materials
Mechanical Properties of Engineering Materials
Rutherford Atomic Model
Bohrs Atomic Model
Chemical Properties of Materials
Energy Bands in Crystals
Electrical Properties of Engineering Materials
Fermi Dirac Distribution Function
Magnetic Properties of Engineering Materials
Selection of Material for Engineering Application
Bases of existence of properties in materials
Low Resistivity or High Conductivity of Conducting Material
High Resistivity or Low Conductivity Conducting Material
Factors Effecting the Resistivity of Electrical Materials
Materials used for Heating Elements
Materials used for Precious Works
Materials Used for Transmission Line Conductor
Electrical Stranded Conductors
Materials used for Rheostats
Materials for Lamp Filaments
Classification of Electrical Conducting Material
Applications of Carbon Materials in Electrical Engineering
Selection of Materials Used for Electrical Contacts
Mechanism of Polarization
Dielectric Material as an Electric Field Medium
Electric Arc Furnace
Thermal Conductivity of Metals
Free Electron Theory of Metals
Thomson Plum Pudding Model (1911)
Magnetic Properties of Engineering Materials
- Retentivity or Magnetic Hysteresis
- Coercive force
PermeabilityIt is the property of magnetic material which indicates that how easily the magnetic flux is build up in material. Some time is also called as the magnetic susceptibility of material. It is determined by the ratio of magnetic flux density to magnetizing force producing this magnetic flux density. It is denoted by µ.
Hence, μ = B/H Where, B is the magnetic flux density in material in Wb/m2 H is the magnetizing force of magnetic flux intensity in Wb/ Henry-meter SI unit of magnetic permeability is Henry / meter Permeability of material is also defined as, μ=μ0 μr Where, µ0 is the permeability of air or vacuum, and μ0 = 4π × 10-7 Henry / meter and µr is the relative permeability of material. µr = 1 for air or vacuum. A material selected for magnetic core in electrical machines should have high permeability, so that required magnetic flux can be produced in core by less ampere- turns.
RetentivityWhen a magnetic material is placed in an external magnetic field, its grains get oriented in the direction of magnetic field. Which results in magnetization of material in the direction of external magnetic field. Now, even after removal of external magnetic field, some magnetization exists, which is called residual magnetism. This property of material is called Magnetic retentively of material. A hysteresis loop or B-H cure of a typical magnetic material is shown in figure below. Magnetization Br in below hysteresis loop represents the residual magnetism of material.
Coercive ForceDue to retentivity of material, even after removal of external magnetic field some magnetization exists in material. This magnetism is called residual magnetism of material. To remove this residual magnetization, we have to apply some external magnetic field in opposite direction. This external magnetic motive force (ATs) required to overcome the residual magnetism is called “coercive force” of material. In above hysteresis loop, - Hc represents the coercive force. The material having large value of residual magnetization and coercive force are called magnetically hard materials. The material having very low vale of residual magnetization and coercive force are called magnetically soft materials.
ReluctanceIt is a property of magnetic material which resists to buildup of magnetic flux in material. It is denoted by R. Its unit is “Ampere-turns / Wb”. Reluctance of magnetic material is given by, A magnetic material suitable for core of electrical machines should have low reluctance.
Closely Related Articles Electrical Engineering MaterialsWhat is an Atom?Atomic Energy LevelsClassification of Engineering MaterialsClassification of Electrical Engineering MaterialsElectron Configuration of AtomPhysical Properties of MaterialsMechanical Properties of Engineering MaterialsRutherford Atomic ModelBohrs Atomic Model Chemical Properties of MaterialsEnergy Bands in CrystalsElectrical Properties of Engineering MaterialsFermi Dirac Distribution FunctionThermionic EmissionSelection of Material for Engineering ApplicationBases of existence of properties in materialsQuantum NumbersLow Resistivity or High Conductivity of Conducting MaterialHigh Resistivity or Low Conductivity Conducting MaterialFactors Effecting the Resistivity of Electrical MaterialsMaterials used for Heating ElementsMaterials used for Precious WorksMaterials Used for Transmission Line ConductorElectrical Stranded ConductorsElectrical ConductorMaterials used for RheostatsMaterials for Lamp FilamentsClassification of Electrical Conducting MaterialApplications of Carbon Materials in Electrical EngineeringSelection of Materials Used for Electrical ContactsBimetalsIonic PolarizationPiezoelectricityDielectric MaterialsMechanism of PolarizationDielectric Material as an Electric Field MediumOrientational PolarizationElectric Arc FurnaceThermal Conductivity of MetalsFree Electron Theory of MetalsMagnetostrictionAntiferroelectricityFerroelectric MaterialsElectronic PolarizationFerromagnetic MaterialsMore Related Articles Thomson Plum Pudding Model (1911)New Articles Principle of Water Content Test of Insulating OilCollecting Oil Sample from Oil Immersed Electrical EquipmentCauses of Insulating Oil DeteriorationAcidity Test of Transformer Insulating OilMagnetic Flux