D.c. Generators

$$rac{{ ext{E}}}{2}$$

2E

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. $$rac{{ ext{E}}}{2}$$ B. 2E C. Slightly less than E

E

Identified by the scarring of the commutator segment to which open circuited coil is connected

Indicated by a spark completely around the commutator

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)

None of the above

Voltage generated is less than the rated voltage

Generated voltage is proportional to the load on the generator

Voltage remains constant irrespective of the load

Speed varies in proportion to the load on the generator

To avoid sudden loading of the prime mover

To avoid mechanical jerk to the shaft

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

All above

Zero

Small

generator, the induced e.m.f. at zero speed will be A. Zero B. Small C. The same as rated voltage

High