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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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. Here, motor is drawing 25 A current at 1500 rpm.

What is the available torque (N-m) at shaft?

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Q. When Ea>Vt machine is said to be operating in which of the following mode?

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Q. When Ea<Vt machine is said to be operating in which of the following mode?

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Q. Simple equation of DC machine operating in generating mode, with non-zero Ra value is________

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Q. Simple equation of DC machine operating in motoring mode, with non-zero Ra value is________

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Q. When torque of the electromagnetic origin is in the opposite direction of rotation of armature, machine is said to be operating in which of the following mode?

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Q. When torque of the electromagnetic origin is in the direction of rotation of armature, machine is said to be operating in which of the following mode?

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Q. What is the armature current for a DC motor if terminal voltage is 255 V and open circuit voltage is equal to 250 V, where armature resistance is 0.05 Ω?

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