DC Generator Objective Type Question Answer

81. Due to armature reaction, the main pole flux of a d.c. generator is

(i) weakened only
(ii) distorted only
(iii) weakened as well as distorted
(iv) none of the above

82. The 0.C.C. of a d.c. generator is also called its ……. characteristic.

(i) magnetic
(ii) internal
(iii) external
(iv) performance

83. The line representing the critical resistance of a d.c. generator ……. its O.C.C.

(i) intersects
(ii) runs parallel to
(iii) just touches
(iv) none of the above

84. Which of the following generator provides approximately constant voltage from no-load to full-load ?

(i) series
(ii) shunt
(iii) flat-compounded
(iv) over-compounded

85. A shunt generator gives its greatest voltage at

(i) no-load
(ii) full-load
(iii) half full-load
(iv) none of the above

86. The level of compounding in a cumulatively compounded d.c. generator is generally adjusted by

(i) changing series field current
(ii) changing shunt field current
(iii) connecting it long-shunt
(iv) connecting it shod-shunt

87. The d.c. generator that has poorest voltage is

(i) shunt generator
(ii) over-compounded generator
(iii) flat-compounded generator
(iv) series generator

88. If P is the number of poles of a generator and N is the armature speed in r.p.m., then frequency of magnetic reversals is

(i) f = NP/120
(ii) f = NP/60
(iii) f = NP/240
(iv) f = NP/30

89. If the value of shunt field resistance of a shunt generator is greater than the critical resistance, the generator will

(i) excite to full voltage
(ii) fail to excite
(iii) excite to one-half of full-voltage
(iv) none of the above

90. The no-load voltage of a generator is 240 V and rated-load voltage is 220 V. The voltage regulation of the generator is

(i) 4.5%
(ii) 11.3%
(iii) 2.8%
(iv) 9.1%

91. The O.C.C. of a d.c. generator is also called its ……. characteristic.

(i) internal
(ii) external
(iii) no-load saturation
(iv) performance

92. The O.C.C. of a d.c. generator

(i) is similar for all types of generators
(ii) is different for different generators
(iii) may be same or different
(iv) none of the above