Q. Nature of the flux density wave in the air gap is__________ (for armature current equal to 0)

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Q. In a DC machine, average energy stored in the magnetic field remains constant independent of the armature rotation.

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Q. Emf produced by DC machine, for zero armature current (E1) and non-zero armature current (E2) can be related as__________

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Q. Average coil emf for 20 coil turns (E1) and 40 coil turns (E2), will have ratio E1/E2=____ (assuming all other parameters same for both machines).

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Q. What is the average coil emf generated in a 4-pole DC machine having flux/pole equal to 0.1 wb rotating at 1500 rpm? (No. of coil sides = 100)

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Q. Emf and torque produced in a DC machine are proportional to ________ and _________ respectively.

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Q. What is the value of Np in an average coil emf equation, for 10 armature conductors with 2 parallel paths?

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Q. What is the torque equation in terms of B, Ic, l, Zr (r= mean air gap radius)?

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Q. What is the value of pole pitch (in SI unit) for mean air gap radius= 0.5 mm and P=4?

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Q. 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?

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Q. 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 induced emf?

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Q. Coil torque for 20 kA armature current (T1) and 40 mA armature current (T2), will have ratio T1/T2=____ (assuming all other parameters same for both machines).

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Q. If the no load speed of DC motor is 1300 rpm and full load speed is 1100 rpm, then its voltage regulation is ____________

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Q. If the average coil emf of a DC motor is doubled and flux is halved (keeping other parameters constant) then its shaft speed will become ___________

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Q. A 4-pole wave wound DC motor drawing an armature current of 20 A has provided with 360 armature conductors. If the flux per pole is 0.015 Wb then the torque developed by the armature of motor is _______

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Q. In a DC machine, what is the torque induced beyond the pole shoes?

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Q. For a constant emf, if field current is reduced then the speed of the DC motor will_____

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Q. For an ideal DC machine, which phenomenon will reduce the terminal voltage?

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Q. Product of torque and mechanical angular velocity ω is_____

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Q. Condition for linear magnetization is______

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