Electrical Transformers: Construction and Operation - Online Learning Quizzes

Question 1

What is the main purpose of an electrical transformer?

Accepted Answer

To move electrical energy between circuits while changing the voltage

Answer

To create electricity

Answer

To change AC to DC

Answer

To keep electrical circuits safe from too much power

Question 2

Which of the following is the fundamental function of an electrical transformer?

Accepted Answer

To elevate or lower voltage

Answer

To change electrical energy into mechanical energy

Answer

To provide electrical isolation

Answer

To regulate current flow

Question 3

What is the designation for the transformer windings that receive electrical power?

Accepted Answer

Primary windings

Answer

Secondary windings

Answer

Core windings

Answer

Flux windings

Question 4

Which material is predominantly used to construct the core of a transformer?

Accepted Answer

Iron

Answer

Copper

Answer

Aluminum

Answer

Silicon

Question 5

Which of the following is not a type of transformer connection configuration?

Accepted Answer

Parallel

Answer

Delta-delta

Answer

Wye-wye

Answer

Delta-wye

Question 6

What is the purpose of laminations in a transformer core?

Accepted Answer

To minimize eddy current losses

Answer

To increase magnetic flux density

Answer

To enhance transformer efficiency

Answer

To improve voltage regulation

Question 7

Which characteristic is associated with a step-up transformer?

Accepted Answer

Increases voltage and decreases current

Answer

Decreases voltage and increases current

Answer

Maintains the same voltage and current ratio

Answer

Converts AC to DC

Question 8

Which type of transformer primarily serves to isolate electrical circuits from each other?

Accepted Answer

Isolation transformer

Answer

Autotransformer

Answer

Power transformer

Answer

Distribution transformer

Question 9

What phenomenon occurs when the core of a transformer reaches magnetic saturation?

Accepted Answer

Saturation

Answer

Eddy currents

Answer

Hysteresis

Answer

Core loss

Question 10

In a transformer, the ratio of the number of turns in the primary winding to the number of turns in the secondary winding determines the transformer's:

Accepted Answer

Turns ratio

Answer

Power factor

Answer

Current rating

Answer

Insulation resistance

Question 11

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

Accepted Answer

To increase voltage, decreasing current

Answer

To decrease voltage, increasing current

Answer

To regulate voltage and current simultaneously

Answer

To convert alternating current (AC) to direct current (DC)

Question 12

In a step-down transformer, which coil has more turns?

Accepted Answer

Secondary coil

Answer

Primary coil

Answer

Both coils have an equal number of turns

Answer

The answer depends on transformer design

Question 13

What type of material is commonly used for transformer cores?

Accepted Answer

Laminated steel

Answer

Solid copper

Answer

Ferrite

Answer

Aluminum

Question 14

What dual purpose does the oil serve in oil-filled transformers?

Accepted Answer

Insulation and cooling

Answer

Conduction of electricity

Answer

Improving efficiency and reducing noise

Answer

Reducing noise and increasing efficiency

Question 15

Why is proper grounding essential in transformer installations?

Accepted Answer

Ensuring safety during fault conditions

Answer

Enhancing transformer efficiency

Answer

Reducing transformer noise

Answer

Not applicable to transformer installations

Question 16

Explain the purpose and operation of autotransformers. Discuss their advantages and disadvantages compared to conventional transformers.

Accepted Answer

Autotransformers can step up or step down voltage, are more economical than conventional transformers, and are not electrically isolated.

Answer

Autotransformers can only step down voltage, are more expensive than conventional transformers, and are electrically isolated.

Answer

Autotransformers can only step up voltage, are less efficient than conventional transformers, and are electrically isolated.

Question 17

How does the load connected to a transformer affect its efficiency?

Accepted Answer

Heavier loads decrease efficiency.

Answer

Heavier loads increase efficiency.

Answer

Load has no impact on efficiency.

Question 18

What determines the turns ratio in a step-up transformer?

Accepted Answer

Ratio of primary voltage to secondary voltage

Answer

Ratio of secondary current to primary current

Answer

Core material used in the transformer

Answer

Frequency of the AC supply

Question 19

Which type of core is typically utilized in distribution transformers?

Accepted Answer

Laminated core

Answer

Wound core

Answer

Toroidal core

Answer

Amorphous core

Question 20

What is the dual purpose of the oil in an oil-filled transformer?

Accepted Answer

Both insulation and cooling

Answer

Insulation

Answer

Cooling

Answer

Neither of the above

Question 21

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

Accepted Answer

To decrease voltage

Answer

To increase voltage

Answer

To change frequency

Answer

To isolate circuits

Question 22

What is the key distinction between an ideal transformer and a real-world transformer?

Accepted Answer

Ideal transformers have no losses, unlike real-world transformers.

Answer

Real-world transformers have a higher turns ratio than ideal transformers.

Answer

Ideal transformers can operate at any frequency, unlike real-world transformers that have frequency limitations.

Answer

Ideal transformers are unaffected by temperature, unlike real-world transformers.

Question 23

To evaluate the integrity of transformer winding insulation, which testing method is recommended?

Accepted Answer

Polarization index test

Answer

Continuity test

Answer

Dielectric strength test

Answer

Capacitance test

Question 24

In a transformer, which component facilitates the transfer of energy from the primary to the secondary winding?

Accepted Answer

Windings

Answer

Core

Answer

Insulation

Answer

Yoke

Question 25

What is the primary reason for laminating the transformer core?

Accepted Answer

Reduce eddy current losses

Answer

Enhance magnetic flux density

Answer

Increase mechanical strength

Answer

Improve heat dissipation

Question 26

The ratio of primary winding turns to secondary winding turns in a transformer is known as:

Accepted Answer

Turns ratio

Answer

Voltage ratio

Answer

Flux density ratio

Answer

Ampere-turn ratio

Question 27

What is the primary purpose of a conservator tank in an oil-immersed transformer?

Accepted Answer

Accommodate oil volume variations due to temperature changes

Answer

Provide a reservoir for spare oil

Answer

Isolate the transformer from the surrounding environment

Answer

Enhance heat dissipation

Question 28

Electrical transformers primarily serve which purpose in electrical circuits?

Accepted Answer

Altering voltage levels

Answer

Converting AC to DC

Answer

Controlling current flow

Answer

Storing electrical energy

Question 29

In a step-up transformer, the ratio of primary to secondary coil turns is:

Accepted Answer

Greater than 1

Answer

Less than 1

Answer

Equal to 1

Answer

Cannot be determined

Question 30

Which type of transformer is used to reduce the voltage level in an electrical circuit?

Accepted Answer

Step-down transformer

Answer

Step-up transformer

Answer

Isolation transformer

Answer

Autotransformer

Question 31

The material separating the primary and secondary coils of a transformer is known as:

Accepted Answer

Insulation

Answer

Core

Answer

Winding

Answer

Laminations

Question 32

Which advantage is offered by laminated steel cores in transformers?

Accepted Answer

Reduced eddy current losses

Answer

Increased hysteresis losses

Answer

Enhanced insulation

Answer

Higher magnetic saturation

Question 33

What is the purpose of the tap changer on a transformer?

Accepted Answer

Adjusting the voltage ratio

Answer

Changing the phase angle

Answer

Isolating the transformer

Answer

Regulating the current

Question 34

The term for the ratio of output power to input power in a transformer is:

Accepted Answer

Efficiency

Answer

Power factor

Answer

Regulation

Answer

Turns ratio

Question 35

In electrical transformer work, which safety measure is paramount?

Accepted Answer

Donning proper Personal Protective Equipment (PPE)

Answer

Utilizing equipment with known faults

Answer

Ignoring cautionary labels on transformers

Answer

Working alone without a qualified partner

Question 36

How does a tap changer contribute to voltage regulation in a transformer?

Accepted Answer

By adjusting the turns ratio between the primary and secondary windings

Answer

By controlling the current flow through the transformer

Answer

By changing the operating frequency of the transformer

Answer

By protecting the transformer from overloads

Question 37

Identify the component that is NOT typically found in an electrical transformer.

Accepted Answer

Capacitor

Answer

Primary winding

Answer

Magnetic core

Answer

Secondary winding

Question 38

What is the primary function of the magnetic core in a transformer?

Accepted Answer

To provide a low reluctance path for magnetic flux

Answer

To insulate the windings

Answer

To regulate voltage

Answer

To store energy

Question 39

Which type of transformer is employed to increase the voltage level in a circuit?

Accepted Answer

Step-up transformer

Answer

Autotransformer

Answer

Step-down transformer

Answer

Isolation transformer

Question 40

How is the voltage transformation ratio of a transformer related to the turns ratio?

Accepted Answer

The voltage ratio is directly proportional to the turns ratio.

Answer

The voltage ratio is inversely proportional to the turns ratio.

Answer

The voltage ratio is equal to the turns ratio.

Answer

The voltage ratio is independent of the turns ratio.

Question 41

When the load on a transformer increases, what happens to the secondary voltage?

Accepted Answer

It decreases.

Answer

It fluctuates randomly.

Answer

It remains the same.

Answer

It increases.

Question 42

What is the theoretical maximum efficiency of an ideal transformer?

Accepted Answer

100%

Answer

90%

Answer

50%

Answer

75%

Question 43

Why is laminated steel commonly used in the construction of transformer cores?

Accepted Answer

To reduce eddy current losses

Answer

To increase magnetic flux density

Answer

To reduce hysteresis losses

Answer

To improve insulation

Question 44

What is the primary function of an electrical transformer?

Accepted Answer

To transfer electrical energy from one circuit to another while modifying its voltage or current

Answer

To generate electrical energy

Answer

To store electrical energy

Question 45

In a step-up transformer, the voltage on the secondary side is:

Accepted Answer

Higher than the voltage on the primary side

Answer

Not related to the voltage on the primary side

Answer

Lower than the voltage on the primary side

Question 46

Which type of transformer is used to reduce the voltage of an electrical circuit?

Accepted Answer

Step-down transformer

Answer

Step-up transformer

Answer

Isolation transformer

Question 47

Which material is commonly used to construct transformer cores because of its magnetic properties?

Accepted Answer

Laminated steel

Answer

Copper

Answer

Plastic

Answer

Aluminum

Question 48

Which factors affect the efficiency of a transformer?

Accepted Answer

Core losses and copper losses

Answer

Capacitance only

Answer

Inductance only

Answer

Neither core losses nor copper losses

Question 49

What is a primary safety concern associated with electrical transformers?

Accepted Answer

High voltage

Answer

Non-flammable materials

Answer

Low operating temperatures

Answer

Low current

Question 50

The magnetic field created in the core of a transformer is:

Accepted Answer

Alternating

Answer

Direct

Answer

Static

Answer

Non-existent

Question 51

Neglecting losses, the power transferred from the primary to the secondary side of a transformer is:

Accepted Answer

Equal

Answer

Greater on the primary side

Answer

Not related to the power on the other side

Answer

Greater on the secondary side