1. The demagnetising component of armature reaction in a D.C. generator ?

reduces generator e.m.f.

increases armature speed

reduces inter poles flux density

results in sparking trouble

Answer: reduces generator e.m.f.


2. An exciter for a turbo generator is a ?

separately excited generator

shunt generator

series generator

compound generator

Answer: shunt generator


3. In a shunt generator the voltage build up is generally restricted by ?

speed limitation

armature heating

insulation restrictions

saturation of iron

Answer: saturation of iron


4. Which generator would you prefer for feeding long D.C. transmission lines ?

Series generator

Shunt generator

Over compound generator

Flat compound generator

Answer: Over compound generator


5. The open circuit voltage of a compound generator is 250 V. At full load the terminal voltage ?

will be less than 250 V

will always be 250 V

may be greater or less than 250 V

none of the above

Answer: may be greater or less than 250 V


6. ln a DC machine, fractional pitch winding is used ?

to increase the generated voltage

to reduce sparking

to save the copper because of shorter end connections

due to (b) and (c) above

Answer: due to (b) and (c) above


7. Which of the following D.C. generators will be in a position to build up without any residual magnetism in the poles ?

Series generator

Shunt generator

Compound generator

None of the above

Answer: None of the above


8. ln case of D.C. generators, the armature voltage control is considered as suitable if the machine is driven ?

at constant load

at constant current

at constant torque

at constant VA

Answer: at constant torque


9. ln D.C. generators on no-load, the air gap flux distribution in space is ?




flat topped

Answer: flat topped


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

Dummy coils


Eye bolt

Equilizer rings

Answer: Commutator