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Calculate the loss of energy caused by hysteresis in one hour in 50 kg of iron if the peak density reached is 1.3 Wb/m2 and the frequency is 25 Hz. Assume Steinmetz coefficient as 628 J/m3 and density of iron as 7.8 × 103 kg/m3 . What will be the area of B/H curve of this specimen if 1cm = 12.4AT/m and 1 cm = 0.1 Wb/m2. |
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Answer» Wh = ηB1.6max fV watt; Volume V = 50/(7.8 x 103) = 6.41 x 10-3m3 ∴ Wh = 628 × 1.31.6 × 25 × 6.41 × 10− 3 = 152 J/s Loss in one hour = 153 × 3,600 = 551,300 J As per Steinmetz law, hysteresis loss = ηB1.6max J/m3/cycle Also, hysteresis loss = xy (area of B/H loop) Equating the two, we get 628 × 1.31.6 = 12.5 × 0.1 × loop area ∴ loop area = 628 × 1.31.6/1.25 = 764.3cm2 |
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