Solved Question Paper for Lecturer in Electrical Engineering in DTTE, GNCTD conducted by UPSC

81. A 440 𝑉 dc series motor of negligible resistance and with unsaturated magnetic circuit takes 50 𝐴 when running at a certain speed on a given load. If the load torque varies as the cube of the speed, the resistance necessary to reduce the speed by 50 % will be:

(a) 20.5 Ω
(b) 24.0 Ω
(c) 28.5 Ω
(d) 32.0 Ω

Answer: (a)

82. A 220 𝑉 shunt motor has an armature resistance of 0.5 Ω and takes armature current of 40 𝐴 at full load. To raise the speed by 50 % if developed torque is constant, the main flux to be reduced will be:
(a) 49.0 %
(b) 45.0 %
(c) 41.5 %
(d) 37.5 %

Answer: (d)

83. A 3-phase, 6-pole induction motor is connected to a 60 Hz supply. The voltage induced in the rotor bars is 4 𝑉 when the rotor is at standstill. The voltage and frequency induced in the rotor bars at 300 rpm will be:
(a) 3 𝑉 and 45 Hz
(b) 3 𝑉 and 55 Hz
(c) 4 𝑉 and 45 Hz
(d) 4 𝑉 and 55 Hz

Answer: (a)

84. 
Which of the above statements are correct?
(a) 1, 2 and 3
(b) 1 and 2 only
(c) 1 and 3 only
(d) 2 and 3 only

Answer: (b)

85. A 3300 𝑉 , delta-connected motor has a synchronous reactance per phase (delta) of 18 Ω. It operates at a leading power factor of 0.707 when drawing 800 kW from the mains. The excitation emf will be:
(a) 2871 𝑉
(b) 2653 𝑉
(c) 2435 𝑉
(d) 2217 𝑉

Answer: (a)

86. Which of the following are the essential elements of an automatic control system?
1. Controller which normally incorporates power amplification
2. A comparison device or error detector
3. A measuring device

(a) 1 and 2 only
(b) 1 and 3 only
(c) 2 and 3 only
(d) 1, 2 and 3

Answer: (d)

87. In transmission lines, non uniformity of current distribution is caused by:
(a) Hall effect
(b) Proximity effect
(c) Faraday effect
(d) Inductive effect

Answer: (b)

88. The ratio error regarding accuracy of a current transformer depends on:
1. Nominal ratio
2. Secondary current
3. Primary current

(a) 1, 2 and 3
(b) 1 and 2 only
(c) 1 and 3 only
(d) 2 and 3 only

Answer: (a)

89. In power system relays the load shed depends on:
1. Self regulating factor 𝑑𝑑
2. Power deficit in percent 𝐷𝐷
3. System normal frequency 𝑓𝑓𝑠
4. Frequency at any time 𝑓𝑓

(a) 1, 2 and 3 only
(b) 1, 2 and 4 only
(c) 3 and 4 only
(d) 1, 2, 3 and 4

Answer: (d)

90. Which one of the following is not a main block of solid-state relays?
(a) Circuit breakers
(b) Comparators
(c) Time delay units
(d) Level detectors

Answer: (a)

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