Transformers MCQs (Part-12)

What is the primary function of a power transformer?

A To step down voltage for residential use
B To step up or step down high-voltage levels for power transmission
C To regulate the current in the system
D To prevent transformer overheating

Which test is used to determine the efficiency of a transformer under load?

A Short-circuit test
B Open-circuit test
C Load test
D Insulation test

What does the equivalent circuit of a transformer represent?

A The physical construction of the transformer
B The electrical properties of the transformer in a simplified form
C The cooling system of the transformer
D The safety mechanisms in the transformer

What is the primary cause of impedance in a transformer?

A The resistance of the windings
B The magnetizing current
C The leakage flux
D The turns ratio

What is the effect of harmonics on transformer operation?

A They increase the efficiency of the transformer
B They cause heating and increased losses
C They improve voltage regulation
D They reduce the transformer’s operational lifespan

What is the purpose of an insulation resistance test on a transformer?

A To measure core losses
B To test the transformer’s insulation system
C To check the impedance of the transformer
D To evaluate the load capacity of the transformer

What is the role of a short-circuit test in transformer testing?

A To measure core losses
B To measure copper losses
C To check the insulation resistance
D To measure the efficiency of the transformer

What is an earthing transformer used for?

A To step up voltage in a distribution system
B To provide a neutral point for grounding in an ungrounded system
C To step down voltage for residential use
D To reduce transformer size

Which of the following is a fault commonly found in transformers?

A Voltage regulation
B Overload fault
C Insulation breakdown
D All of the above

What is the role of a load test in transformer performance evaluation?

A To assess the transformer’s performance under actual load conditions
B To measure core losses
C To determine the copper losses
D To measure the efficiency of insulation

What is the effect of harmonics on transformer operation?

A They improve transformer efficiency
B They cause heating and increased losses
C They improve voltage regulation
D They have no effect on transformer operation

What is the function of an isolation transformer?

A To electrically isolate the primary and secondary circuits
B To step up or step down voltage
C To regulate voltage
D To measure current

What is the main advantage of parallel operation of transformers?

A It increases the overall system capacity and reliability
B It reduces voltage fluctuation
C It decreases transformer losses
D It steps up voltage

What is the typical efficiency range of modern transformers?

A 50-60%
B 70-80%
C 80-90%
D 90-98%

What is the function of the primary winding in a transformer?

A To generate magnetic flux
B To regulate voltage output
C To provide insulation
D To dissipate heat

What is the typical application of a distribution transformer?

A To step down voltage for residential and commercial use
B To step up voltage for transmission
C To regulate voltage in industrial applications
D To isolate electrical circuits

What is the purpose of the insulation resistance test in transformers?

A To test the condition of the transformer’s insulation
B To measure the transformer’s impedance
C To measure the core loss
D To test the transformer’s efficiency

What is the typical frequency of transformers used in the power grid?

A 50 Hz or 60 Hz
B 100 Hz
C 200 Hz
D 500 Hz

What is the role of the secondary winding in a transformer?

A To generate magnetic flux
B To supply power to the load
C To regulate the voltage output
D To dissipate heat

What is the primary purpose of a voltage regulator transformer?

A To maintain a constant voltage under varying load conditions
B To step up voltage for long-distance transmission
C To regulate the transformer’s temperature
D To reduce current in the system