Relation between Magnetic Flux density ( B ) and Magnetic Field Strength ( H )

 

Magnetic flux density ( B )

• It is defined as the magnetic flux per unit area of surface at right angle to the magnetic field. Its unit is weber per meter square

       B = Φ / A

      Where Φ = Flux in weber and

                  A = Surface area

Magnetic field intensity ( H )

• The magnetic field intensity is the force required to maintain magnetic flux and it will produces particular value of magnetic flux. 
• The magnetic field strength is measure of magnetic field produced by electrical current flows through coil. 
• The magnetic flux density is directly proportional to magnetic field intensity.

      B α H

      B = μH

      Where μ = Constant

                 μ = μ₀ μ_r

      Where μ₀ = Permeability of free space

                     = 4π × 10 ^{– 7} weber / ampere - meter

               μ_r  = Relative permeability of the medium

Relative Permeability of different Medium

Medium	Relative Permeability
Air	1
Carbon steel	100
Electrical steel	4000
Super conductor	0

 

You may also like :

Constant Voltage Transformer

Constant Current Transformer

Earthing Transformer

Compare : Salient Pole Alternator – Cylindrical PoleAlternator