[amp_mcq option1=”$$\frac{{\text{E}}}{2}$$” option2=”2E” option3=”generator is E. Now while pole flux remains constant, if the speed of the generator is doubled, the e.m.f. generated will be A. $$\frac{{\text{E}}}{2}$$ B. 2E C. Slightly less than E” option4=”E” correct=”option2″]
D.c. Generators
2. Open circuited armature coil of a D.C. machine is
[amp_mcq option1=”Identified by the scarring of the commutator segment to which open circuited coil is connected” option2=”Indicated by a spark completely around the commutator” option3=”machine is A. Identified by the scarring of the commutator segment to which open circuited coil is connected B. Indicated by a spark completely around the commutator C. Both (A) and (B)” option4=”None of the above” correct=”option2″]
Detailed SolutionOpen circuited armature coil of a D.C. machine is
3. In case of a flat compounded generator
[amp_mcq option1=”Voltage generated is less than the rated voltage” option2=”Generated voltage is proportional to the load on the generator” option3=”Voltage remains constant irrespective of the load” option4=”Speed varies in proportion to the load on the generator” correct=”option3″]
4. D.C. generators are connected to the bus-bars or disconnected from them only under the floating condition
[amp_mcq option1=”To avoid sudden loading of the prime mover” option2=”To avoid mechanical jerk to the shaft” option3=”generators are connected to the bus-bars or disconnected from them only under the floating condition A. To avoid sudden loading of the prime mover B. To avoid mechanical jerk to the shaft C. To avoid burning of switch contacts” option4=”All above” correct=”option4″]
5. If residual magnetism is present in a D.C. generator, the induced e.m.f. at zero speed will be
[amp_mcq option1=”Zero” option2=”Small” option3=”generator, the induced e.m.f. at zero speed will be A. Zero B. Small C. The same as rated voltage” option4=”High” correct=”option2″]