Q. Maximum allowable current for a 240-V DC shunt motor is equal to 65 A. Minimum allowable current for same is equal to 40 A. What will be the value of γ?

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Q. For a certain machine having γ = 1.8, we are using starter with 5 steps. What will be the resistance at step 3 if step 2 resistance is equal to 2 Ω?

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Q. Which of the following is the correct formula for calculating step resistance?

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Q. Which of the following starter can sufficiently start the DC series motor?

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Q. The speed of a DC shunt motor can be increased by ______

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Q. What will happen if excitation of DC shunt motor is changed?

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Q. If the speed of a DC shunt motor is increased, the back emf of the motor will ___________

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Q. The speed of a DC shunt motor can be made more than full load speed by __________

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Q. Speed regulation of DC shunt motor is calculated by ratio of difference of full load speed and no-load speed with full load speed.

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Q. Which speeds can be obtained from field control of DC shunt motor?

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Q. No load speed of the DC shunt motor is 1322 rpm while full load speed is 1182 rpm. What will be the speed regulation?

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Q. Speed regulation of a DC shunt motor is equal to 10%, at no load speed of 1400 rpm. What is the full load speed?

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Q. Where will speed-torque characteristics will lie when armature reaction is considered?

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Q. Working range of the speed-torque characteristic, with increasing speed will ___________

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Q. For speed x rpm, we get field current If₁ and for speed y rpm, we get the field current If₂. If y is greater than x then, ________________

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Q. 400-V dc shunt motor takes a current of 5.6 A on no-load and 68.3 A on full-load. Armature reaction weakens the field by 3%. What is the ratio of full-load speed to no-load speed? Given: Ra = 0.18 Ω, brush voltage drop= 2 V, Rf = 200 Ω.

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Q. In which of the following method, effect of armature reaction is more?

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Q. Which of the following DC motor has the poorest speed control?

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Q. In variable speed motor ____________

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Q. The speed of a motor falls from 1200 rpm at no-load to 1050 rpm at rated load. The speed regulation of the motor is ____________

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