Transformers: Interactive Learning Quizzes for Electrical Engineering

Question 1

Explain the negative impacts of harmonics on transformer performance and describe specific techniques used to minimize their effects.

Accepted Answer

Passive LC filters can effectively remove harmonics from the input supply.

Answer

Harmonics have no significant impact on transformer performance and do not require mitigation techniques.

Answer

Oversizing the transformer can fully compensate for the adverse effects of harmonics on its operation.

Answer

Delta-connected transformers are inherently immune to the effects of harmonics.

Question 2

In power distribution systems, which transformer type is commonly utilized?

Accepted Answer

Power transformer

Answer

Autotransformer

Answer

Instrument transformer

Answer

Isolation transformer

Question 3

Laminated silicon steel is typically the material of choice for the core of a transformer due to:

Accepted Answer

Excellent magnetic properties

Answer

High electrical conductivity

Answer

Low cost

Answer

Light weight

Question 4

The relationship between the number of primary and secondary turns in a transformer is defined by:

Accepted Answer

Turns ratio

Answer

Voltage ratio

Answer

Current ratio

Answer

Impedance ratio

Question 5

Which test method is employed to determine the insulation resistance of a transformer?

Accepted Answer

Megger test

Answer

Hi-pot test

Answer

Turn ratio test

Answer

Polarity test

Question 6

The primary function of a Buchholz relay in a transformer is to detect the presence of:

Accepted Answer

Excessive gas accumulation

Answer

Overheating

Answer

Overcurrent

Answer

Under-voltage

Question 7

Which of the following is a key advantage of utilizing autotransformers?

Accepted Answer

Reduced copper requirement

Answer

Enhanced voltage regulation

Answer

Increased isolation

Answer

Lower efficiency

Question 8

The regulation of a transformer is expressed as:

Accepted Answer

Percentage change in secondary voltage from no-load to full-load

Answer

Percentage change in primary current from no-load to full-load

Answer

Percentage change in power factor from no-load to full-load

Answer

Percentage change in efficiency from no-load to full-load

Question 9

Incorrect oil level in a transformer can lead to increased:

Accepted Answer

Noise levels

Answer

Insulation resistance

Answer

Efficiency

Answer

Power factor

Question 10

Which of the following is NOT a function of a transformer?

Accepted Answer

Power generation

Answer

Voltage transformation

Answer

Current transformation

Answer

Impedance matching

Question 11

The core of a transformer is primarily made of:

Accepted Answer

Laminated steel

Answer

Copper

Answer

Aluminium

Answer

Silicon

Question 12

The ratio of the number of turns on the primary winding to the number of turns on the secondary winding is known as the:

Accepted Answer

Turns ratio

Answer

Voltage ratio

Answer

Current ratio

Answer

Impedance ratio

Question 13

For high-voltage transmission over extended distances, which type of transformer is typically used?

Accepted Answer

Step-up transformer

Answer

Step-down transformer

Answer

Autotransformer

Answer

Isolation transformer

Question 14

What is the term for the insulation between the windings in a transformer?

Accepted Answer

Inter-winding insulation

Answer

Primary insulation

Answer

Secondary insulation

Answer

Core insulation

Question 15

Which test is commonly used to determine the insulation resistance of a transformer?

Accepted Answer

Megger test

Answer

Breakdown test

Answer

Hipot test

Answer

Continuity test

Question 16

The primary purpose of a transformer is to:

Accepted Answer

Step up or step down voltage levels

Answer

Convert AC voltage to DC voltage

Answer

Isolate circuits electrically

Answer

Store electrical energy

Question 17

Laminated cores are primarily used in which type of transformer?

Accepted Answer

Power transformer

Answer

Distribution transformer

Answer

Autotransformer

Answer

Isolation transformer

Question 18

The main purpose of a cooling system in a transformer is to:

Accepted Answer

Prevent overheating caused by energy loss

Answer

Enhance insulation properties

Answer

Reduce electromagnetic interference

Answer

Improve voltage regulation

Question 19

To determine the efficiency of a transformer, which test is conducted?

Accepted Answer

Load test

Answer

Open-circuit test

Answer

Short-circuit test

Answer

Insulation resistance test

Question 20

An autotransformer is used primarily for:

Accepted Answer

Providing variable AC voltage output

Answer

Isolating circuits

Answer

Significant voltage stepping up or down

Answer

Converting AC to DC

Question 21

Which safety measure is essential during transformer maintenance?

Accepted Answer

Use insulated tools

Answer

Work without supervision

Answer

Touch the transformer windings directly

Question 22

The primary purpose of laminating the transformer core is to:

Accepted Answer

Minimize eddy current losses

Answer

Maximize magnetic flux density

Answer

Enhance insulation properties

Answer

Improve heat dissipation

Question 23

The ideal transformer turns ratio is defined as:

Accepted Answer

Primary turns divided by Secondary turns

Answer

Secondary turns divided by Primary turns

Answer

Primary voltage divided by Secondary voltage

Answer

Primary current divided by Secondary current

Question 24

Which of the following is NOT a major application of transformers in electrical engineering?

Accepted Answer

Energy storage

Answer

Voltage regulation

Answer

Power distribution

Answer

Electrical isolation

Question 25

Increasing the primary voltage of a transformer will result in:

Accepted Answer

An increase in secondary voltage

Answer

A decrease in secondary voltage

Answer

An increase in primary current

Answer

A decrease in primary current

Question 26

What is the primary function of a transformer's core?

Accepted Answer

Provide a magnetic flux path

Answer

Conduct electric current

Answer

Insulate the windings

Answer

Dissipate heat

Question 27

Which of the following is a result of increasing the turns ratio of a transformer?

Accepted Answer

Increased voltage, decreased current

Answer

Decreased voltage, increased current

Answer

Increased current, decreased voltage

Answer

No change in voltage or current

Question 28

What is the primary purpose of a transformer's cooling system?

Accepted Answer

Maintain optimal operating temperature

Answer

Reduce noise

Answer

Increase efficiency

Question 29

Which of the following is a characteristic of a three-phase transformer?

Accepted Answer

Three primary and three secondary windings

Answer

Two primary and two secondary windings

Answer

One primary and three secondary windings

Answer

Three primary and one secondary winding

Question 30

What is the main purpose of a step-up transformer?

Accepted Answer

Increase voltage, decrease current

Answer

Decrease voltage, increase current

Answer

Maintain voltage and current

Answer

Change alternating current to direct current

Question 31

Which material is commonly used for transformer windings?

Accepted Answer

Copper

Answer

Aluminum

Answer

Steel

Answer

Ceramic

Question 32

The primary function of a transformer is to:

Accepted Answer

Change AC voltage levels

Answer

Store energy

Answer

Convert AC to DC

Answer

Filter out harmonics

Question 33

In a transformer, the ratio of secondary voltage to primary voltage is determined by the:

Accepted Answer

Turns ratio

Answer

Current value

Answer

Power factor

Answer

Resistance

Question 34

Which type of transformer core is commonly used in power distribution systems due to its low losses?

Accepted Answer

Laminated steel core

Answer

Solid iron core

Answer

Ferrite core

Answer

Air core

Question 35

The primary purpose of oil insulation in a transformer is to:

Accepted Answer

Provide thermal conduction and electrical insulation

Answer

Enhance magnetic flux

Answer

Reduce humming noise

Question 36

A key advantage of using step-up transformers is:

Accepted Answer

Reducing energy losses during transmission

Answer

Improving motor torque at low speeds

Answer

Increasing the power factor of the system

Answer

Lowering the voltage regulation

Question 37

A transformer with a turns ratio of 3:1 will have a secondary voltage that is:

Accepted Answer

Three times the primary voltage

Answer

Quarter of the primary voltage

Answer

Equal to the primary voltage

Answer

Half of the primary voltage

Question 38

The typical efficiency range of a transformer is approximately:

Accepted Answer

95-98%

Answer

20-40%

Answer

Below 10%

Answer

50-70%