Q. Which motor is preferred in highly explosive atmosphere?

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Q. For which of the following operations a DC motor is preferred over an AC motor?

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Q. The armature in DC machines is always placed on rotor because _______

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Q. In a DC machine, rectification provided with commutator is ___________

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Q. Commutator performs rectification so that output of the machine is bi-directional.

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Q. Which of the following method is used to connect commutator segments to armature conductors?

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Q. In D.C. generators, rapid brush ware causes due to _________

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Q. What are the number of the brushes in the lap winding?

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Q. When Copper brushes are used in DC machine?

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Q. In DC generators, current is fed up to the external circuit from armature through _______

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Q. What are the number of the brushes in the wave winding?

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Q. Which conductors are in point of contact with brushes?

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Q. In case of DC machine winding, number of commutator segments is equal to ______

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Q. How total number of brushes in a commutator are determined in a given DC machine?

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Q. In a DC generator the ripples in the direct emf generated can be reduced by________

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Q. The drop in the voltage for which of the following types of brush can be expected to be least?

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Q. What is the requirement of the good commutation?

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Q. How to avoid grooves in the commutation of DC machine with the help of brush?

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Q. Reason behind the rapid wear of brushes is __________

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Q. For both lap and wave windings, what is the number of commutator bars equal to?

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