Electrical Transformer Multiple choice Question (Electrical Mcqs) and Answer Part 9
Electrical Engineering Objective Question and Answer
161- The kVA delivered by transformer I will be
(A) 55.5
(B) 68.4
(C) 114.4
(D) 144
Answer: (C)
162- The KVA delivered by transformer 2 will be
Answer: (C)
162- The KVA delivered by transformer 2 will be
(A) 185.6
(B) 155.4
(C) 114.4
(D) 100
Answer: (A)
163- A transformer has input voltage of 100 V at 400 Hz. if the number of turns is 375, the peak value of flux will be
Answer: (A)
163- A transformer has input voltage of 100 V at 400 Hz. if the number of turns is 375, the peak value of flux will be
(A) 1.5 μ Wb
(B) 68.4 μ Wb
(C) 114.4 μ Wb
(D) 144 μ Wb
Answer: (C)
164- In a transformer on no load, the input voltage
Answer: (C)
164- In a transformer on no load, the input voltage
(A) leads the magnetizing current by 90°
(B) lags the magnetizing current by 90°
(C) is in phase with magnetizing current
(D) is always at 45° to the magnetizing current
Answer: (A)
Answer: (A)
165- In a transformer the voltage induced in the secondary wingdings
(A) leads the flux by 90°
(B) leads the flux by less than 45°
(C) lags the flux by 90°
(D) lags the flux by less than 45°
Answer: (C)
166- The maximum load that a power transformer can carry is limited by its
Answer: (C)
166- The maximum load that a power transformer can carry is limited by its
(A) voltage ratio
(B) copper loss
(C) temperature rise
(D) dielectric strength of oil
Answer: (A)
167- The losses on a transformer are
1- copper loss 2- Eddy current loss 3- Hysteresis loss
The constant power loss of a transformer loss is given by
Answer: (A)
167- The losses on a transformer are
1- copper loss 2- Eddy current loss 3- Hysteresis loss
The constant power loss of a transformer loss is given by
(A) 1 only
(B) 1 and 2 only
(C) 2 and 3 only
(D) 1 ,2 and 3 only
Answer: (C)
168- For the circuit shown in figure, the primary current will be
Answer: (C)
168- For the circuit shown in figure, the primary current will be
(A) 12.8 A
(B) 8.8 A
(C) 6.4 A
(D) 3.2A
Answer: (C)
169- which of the following test provides the information about regulation, efficiency and heating under load conditions ?
Figure-20
Answer: (C)
169- which of the following test provides the information about regulation, efficiency and heating under load conditions ?
Figure-20
(A)Open circuit test
(B) Short circuit test
(C) Hopkinson's test
(D) Back to back test
Answer: (D)
An open circuit test on a certain transformer produced the following measurements :
Primary voltage 115 V
Secondary voltage 57.5 V
Power 9.5 W
No load primary current 180 mA.
170- the transformer turns ratio is
Fig. 21
Answer: (D)
An open circuit test on a certain transformer produced the following measurements :
Primary voltage 115 V
Secondary voltage 57.5 V
Power 9.5 W
No load primary current 180 mA.
170- the transformer turns ratio is
Fig. 21
(A) Ns : Np :: 1 : 2
(B) Ns : Np :: 2:1
(C) Ns : Np :: 2:3
(D) Ns : Np :: 3:2
Answer: (A)
Question 171 to 176 refer to figure below :
The transformer shown in figure has an alternating input of 100 V. The number of turns on each winding are
Np = 375 , Ns1 = 750 , Ns2 = 500 and Ns3 = 75
171- The output ES1 will be
Answer: (A)
Question 171 to 176 refer to figure below :
The transformer shown in figure has an alternating input of 100 V. The number of turns on each winding are
Np = 375 , Ns1 = 750 , Ns2 = 500 and Ns3 = 75
171- The output ES1 will be
(A) 200 V
(B) 133 V
(C) 20 V
(D) 353 V
Answer: (B)
172- The output voltage ES2 will be
Answer: (B)
172- The output voltage ES2 will be
(A) 200 V
(B) 133 V
(C) 20 V
(D) 353 V
Answer: (B)
173- The output voltage Es3 will be
Answer: (B)
173- The output voltage Es3 will be
(A) 10 V
(B) 20 V
(C) 40 V
(D) 80 V
Answer: (B)
174- The total output voltage if all three secondary winding were connected series-aiding, will be
Answer: (B)
174- The total output voltage if all three secondary winding were connected series-aiding, will be
(A) 200 V
(B) 200 x 133 x 20 V
(C) 353 V
(D) 353 √2 V
Answer: (C)
175- if three secondary windings have load as Rs1 = 1 K Ω .Rs2= 500 Ω and Rs3 = 100 Ω , assuming transformer to be 100% efficient , the maximum current will flow through
Answer: (B)
176- In the above case the total primary current will be
Answer: (C)
175- if three secondary windings have load as Rs1 = 1 K Ω .Rs2= 500 Ω and Rs3 = 100 Ω , assuming transformer to be 100% efficient , the maximum current will flow through
(A) Rs1
(B) Rs2
(C) Rs3
Answer: (B)
176- In the above case the total primary current will be
(A) 400 mA
(B) 666 mA
(C) 705 mA
(D) 795 mA
Answer: (D)
Question 177 and 178 refer to data given below :
An iron-core transformer has a primary inductance of 0.2 H, a secondary inductance of 50 mH, and a turn ratio of 2:1. The winding resistance are measured as Rp = 2 ohms and Rs = 1 ohm.
Answer: (D)
Question 177 and 178 refer to data given below :
An iron-core transformer has a primary inductance of 0.2 H, a secondary inductance of 50 mH, and a turn ratio of 2:1. The winding resistance are measured as Rp = 2 ohms and Rs = 1 ohm.
177- The load voltage for a resistor load of 8 ohms and an input of 16 V at 1 kHz will be
(A) 12.8 V
(B) 8.2 V
(C) 6.4 V
(D) 3.2 V
Answer: (C)
178- Under no load condition the secondary voltage will be
Answer: (C)
178- Under no load condition the secondary voltage will be
(A) 6.4 V
(B) 12 V
(C) 10 V
(D) 8 V
Answer: (D)
Question 179 , 180 refer to figures below :
179- In low frequency range, in case of an iron-core transformer, the output voltage will vary as shown in
Answer: (D)
Question 179 , 180 refer to figures below :
179- In low frequency range, in case of an iron-core transformer, the output voltage will vary as shown in
(A) figure A
(B) figure B
(C) figure C
(D) figure D
Answer: (C)
180- The response of iron core transformer in high frequency range will be as shown in
Answer: (C)
180- The response of iron core transformer in high frequency range will be as shown in
(A) figure A
(B) figure B
(C) figure C
(D) figure D
Answer: (B)
Answer: (B)
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