MULTIPLE CHOICE QUESTIONS
Q.1 The external
characteristic of a shunt generator can be obtained directly from its— characteristic.
(A) internal
(B) open-circuit
(C) load-saturation
(D) performance
Q.2 Load saturation characteristic of a d.c. generator
gives relation between
(A) V and Ia
(B) E and Ia
(C) E0 and If
(D) V and If
Q.3 The slight curvature at the lower end of the O.C.C.
of a self-excited d.c. generator is due to
(A) residual pole flux
(B) high armature speed
(C) magnetic inertia
(D) high field circuit resistance.
Q.4 For the voltage built-up of a self-excited d.c.
generator, which of the following is not an essential condition?
(A) There must be some residual flux
(B) Field winding mmf must aid the residual flux
(C) Total field circuit resistance must be less than the
critical value
(D) Armature speed must be very high.
Q.5 The voltage build-up process of a d.c. generator is
(A) difficult
(B) delayed
(C) cumulative
(D) infinite
Q.6 Which of the following d.c. generator cannot build
up on open-circuit ?
(A) shunt
(B) series
(C) short shunt
(D) long shunt
Q.7 If a self-excited d.c. generator after being
installed, fails to build up on its first trial run, the first thing to do is to
(A) increase the field resistance
(B) check armature insulation
(C) reverse field connections
(D) increase the speed of prime mover.
Q.8 If residual magnetism of a shunt generator is
destroyed accidentally, it may be restored by
connecting its shunt field
(A) to earth
(B) to an a.c. source
(C) in reverse
(D) to a d.c. source.
Q.9 The three factors which cause decrease in the
terminal voltage of a shunt generator are
(A) armature reactances
(B) armature resistance
(C) armature leakages
(D) armature reaction
(E) reduction in field current
Q.10 If field resistance of a d.c. shunt generator is
increased beyond its critical value, the generator
(A) output voltage will exceed its name-plate rating
(B) will not build up
(C) may burn out if loaded to its name-plate rating
(D) power output may exceed its name-plate rating
