A 4-pole Dc wound machine is lap wound with 400 conductors. The pole shore is 20 cm long and average flux density over one-pole pitch is 0.4 T, the armature diameter being 30 cm. What is the value of flux/pole?(a) 0.188 Wb(b) 18.88 Wb(c) 0.0188 Wb(d) 1.888 WbThis question was addressed to me during an interview.I want to ask this question from EMF and Torque Production topic in portion Circuit Model, Emf and Torque of DC Machines

A 4-pole Dc wound machine is lap wound with 400 conductors. The pole s

1.	A 4-pole Dc wound machine is lap wound with 400 conductors. The pole shore is 20 cm long and average flux density over one-pole pitch is 0.4 T, the armature diameter being 30 cm. What is the value of flux/pole?(a) 0.188 Wb(b) 18.88 Wb(c) 0.0188 Wb(d) 1.888 WbThis question was addressed to me during an interview.I want to ask this question from EMF and Torque Production topic in portion Circuit Model, Emf and Torque of DC Machines
Answer» Right option is (c) 0.0188 Wb To explain I would say: Flux is DEFINED as flux density for a GIVEN surface AREA. Here, Surface area can be calculated and multiplied with B to GIVE the value of flux. Flux= 2πrlB. now, for calculating flux per pole, DIVIDE it by P=4. So, Flux per pole after substituting all values is equal to 0.0188 Wb.

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