Determine the maximum flux density (in T) of a material having eddy current coefficient of 2, the thickness of 4 mm, the volume of 20 cu.meter, which is supplied by the frequency of 50 Hz when the material has eddy current loss of 6 W

• A. 3.34
• B. 1.21
• C. 2.24
• D. 1.94

Answer: (D)

Eddy current losses in the transformer is given by
Eddy current losses = Ke × Bm2 × f2 × V ×t2
Where Ke = Eddy current constant = 2t = thickness of the core = 4 mm = 4 × 10−3V = Volume of material = 20m3Bm = Maximum flux density = ? f = frequency = 50 HzEddy current losses = 6W
Now put the above data in the equation we get
6 = 2 × B2m × (50)2 × (4 × 10-3)2 × 20
B2m = 3.75
Bm = 1.94