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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Q. Spacing between the brushes for a 4-pole machine in terms of commutator segments for 12 conductor segments is _____

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Q. Spacing between the brushes for a 4-pole machine in terms of commutator segments is equal to 6. What will be the number of armature slots?

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Q. What is the range of the brush friction coefficients for medium category?

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Q. Specific resistance for a brush is given by _________

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Q. How many poles to be used in DC machine if brushes are placed 4 commutator segments apart for 16 commutator segments?

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Q. DC generators are disconnected/connected from/to the busbars only under the floating condition because ____________

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Q. In PMDC motors we use magnetic material with ___________

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Q. In PMDC magnetic material is placed instead of _____________

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Q. PMDC motors are _________________

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Q. PMDC motor offers ___________

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Q. Which speed control method is employed in PMDC?

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Q. What is the air gap flux density for PMDC motor?

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Q. Which of the following is most favoured choice for PMDC motor?

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