Transformers Multiple Choice Questions & Answers (MCQs) on “Transformer Construction (Winding)”.
1. In the transformer which of the following winding has got more cross-sectional area?
a) Copper winding
b) Steel winding
c) Aluminium winding
d) Iron winding
Answer: a
Clarification: The wire used for carrying current in a transformer winding is either copper or aluminium. While aluminium wire is lighter and less expensive than copper wire, a larger cross-sectional area of conductor must be used to carry the same amount of current as with copper.
2. Primary winding of a transformer ______________
a) Is always a high voltage winding
b) Is always a low voltage winding
c) Could either be a low voltage or high voltage winding
d) Cannot be determined
Answer: c
Clarification: Primary winding used in a transformer, can be at higher or lower voltage potential, depending on the number of turns with secondary winding. For step up and step-down transformers primary winding will be at lower and higher potential respectively.
3. Which winding has more number of turns?
a) Low voltage winding
b) High voltage winding
c) Primary winding
d) Secondary winding
Answer: b
Clarification: High voltage winding always has a large number of turns, as voltage is directly proportional to the number of turns. If large numbered winding is present on primary side then the transformer is step down transformer.
4. Part of the transformer which undergoes most damage from overheating is ___________
a) Iron core
b) Copper winding
c) Winding insulation
d) Frame or case
Answer: c
Clarification: Copper windings carry current through them. The heat loss producing in any winding carrying current is proportional to the square of the current passing through it multiplied with resistance. For large transformers, current is very high, so heating causes most of the damage to insulation material.
5. If a transformer is continuously operated the maximum temperature rise will occur in ___________
a) Core
b) Windings
c) Tank
d) Cannot be determined
Answer: b
Clarification: Copper windings carry currents in a transformer. The loss in form of heat in copper winding carrying current is proportional to the square of the current passing through them multiplied by the resistance of the winding. This loss is dissipated in heat and corresponding temperature rise.
6. If secondary number of turns are higher then, transformer is called _________
a) Step-down
b) Step-up
c) One-one
d) Autotransformer
Answer: b
Clarification: When secondary number of turns are higher compare to primary, voltage induced in secondary windings will obviously high. Thus, this transformer is used for stepping up the output voltage by keeping frequency constant.
7. If primary number of turns are higher then, transformer is called _________
a) Step-down
b) Step-up
c) One-one
d) Autotransformer
Answer: a
Clarification: When primary number of turns are higher compare to secondary, voltage induced in secondary windings will obviously low compare to primary. Thus, this transformer is used for stepping down the output voltage by keeping frequency constant.
8. If a transformer is having equal number of turns at primary and secondary then transformer is called as _______________
a) Step-down
b) Step-up
c) One-one
d) Autotransformer