TRANSFORMERS MCQs SET 13

TRANSFORMERS MCQs SET 13

1. A shell-type transformer has __________
a) High eddy current losses
b) Reduced magnetic leakage
c) Negligible hysteresis losses
d) Cannot be determined 

Answer: b

2. During open circuit test (OC) of a transformer _____________
a) primary is supplied rated kVA
b) primary is supplied full-load current
c) primary is supplied current at reduced voltage
d) primary is supplied rated voltage
 

Answer: d

3. Open circuit test on transformers is conducted so as to get ______________
a) Hysteresis losses
b) Copper losses
c) Core losses
d) Eddy current losses
 

Answer: c

4. Why OC test is performed on LV side?
a) Simple construction
b) Less voltage is required and parameters can be transformed to HV side
c) It’ll not give losses ig conducted on HV side
d) HV side does not have connections for voltage
 

Answer: b

5. In OC test all the power supplied is utilised for ______
a) Core losses
b) Iron losses
c) Windage losses
d) Cannot be determined
 

Answer: b

6. How shunt branch component Gi is calculated?
a) Po/v12
b) V1/Io
c) Io/ V2
d) Any of the above
 

Explanation: Shunt branch resistance inverse is denoted by Gi. This Gi can be calculated by the power drop taking place in the resistance divided by square of the voltage applied across the resistor. Current by voltage will give net admittance.

7. Which of the following statements is/are correct statements?
a) EMF per turn in LV winding is more than EMF per turn in LV winding
b) EMF per turn in LV winding is less than EMF per turn in LV winding
c) EMF per turn in HV winding is equal to EMF per turn in LV winding
d) Can’t comment
 

Answer: c

8. If the applied voltage of a transformer is increased by 50% and the frequency is reduced by 50%, the maximum flux density will _____________
a) Changes to three times the original value
b) Changes to 1.5 times the original value
c) Changes to 0.5 times the original value
d) Remains the same as the original value
 

Answer: a

9. The total core loss can be termed as ____________
a) Eddy current loss
b) Hysteresis loss
c) Copper loss
d) Magnetic loss
 

Answer: d

10. 2 KVA, 230 V, 50 Hz single phase transformer has an eddy current loss of 40 watts. The eddy current loss when the transformer is excited by a dc source of same voltage will be ___________
a) Equal to 40W
b) Less than 40W
c) More than 40W
d) Zero watts
 

Answer: d