DC Motors Objective Questions and Answers

253. Which of the following components of a D.C. generator plays vital role for providing direct current of a D.C. generator?

254. In a D.C. generator the ripples in the direct e.m.f. generated are reduced by

A. using conductor of annealed copper

B. using commutator with large number of segments

C. using carbon brushes of superios quality

D. using equiliser rings

Discussion

255. In D.C. generators, lap winding is used for

A. high voltage, high current

B. low voltage, high current

C. high voltage, low current

D. low voltage, low current

Discussion

256. Two generators A and B have 6-poles each. Generator A has wave wound armature while generator B has lap wound armature. The ratio of the induced e.m.f. is generator A and B will be

257. D.C. generator varies significantly with the load current?

A. Field copper loss

B. Windage loss

C. Armature copper loss

D. None of the above

Discussion

258. The match between the control method needed and the speed/torque regime is as follows P Field Control, Q Armature Control1. Below base speed2. Above base speed3. Above base torque4. Below base torque

259. motor draws 1.5 A from a supply voltage of 25 V and runs at 1500 rpm. The efficiency of the motor while it is operating on load at 1500 rpm drawing a current of 3.5 A from the motor may result in same source

Electrical Engineering Objective Questions { DC Motors }