A 440 V, 4-pole, 25 kW, dc generator has a wave-connected armature winding with 846 conductors. The mean flux density in the air-gap under the interpoles is 0.5 Wb/m^2 on full load and the radial gap length is 0.3 cm. Number of turns required on each interpole is _________(a) 74(b) 84(c) 64(d) 54The question was asked in an online interview.I would like to ask this question from Commutation Process -1 topic in section Commutation Process & Excitation Methods of DC Machines

A 440 V, 4-pole, 25 kW, dc generator has a wave-connected armature win

1.	A 440 V, 4-pole, 25 kW, dc generator has a wave-connected armature winding with 846 conductors. The mean flux density in the air-gap under the interpoles is 0.5 Wb/m^2 on full load and the radial gap length is 0.3 cm. Number of turns required on each interpole is _________(a) 74(b) 84(c) 64(d) 54The question was asked in an online interview.I would like to ask this question from Commutation Process -1 topic in section Commutation Process & Excitation Methods of DC Machines
Answer» RIGHT answer is (a) 74 For explanation: CORRESPONDING value of ampere-turns for an interpole ATi = ATa (peak) +(Bi/µ0) lgi. = Ia* Z/2AP + (Bi/µ0) lgi. Assuming Ia = Iline Ia = 2510^3/440= 56.82 A. ATi = [(56.82846)/ (224)] +(0.5/4π10^-7 ) 0.3*10^-2 =4198. Ni= 4198/56.82= 74.

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