Two transformers are connected in parallel, one has twice the internal impedance of the other,

The lower impedance transformer will overload.

The higher-impedance transformer will carry Jess than half the load of the lower-impedance transformer.

The lower impedance transformer will carry more than twice as much load as the higher impedance transformer.

The lower impedance transformer will overload.

The higher impedance transformer will short circuit.

Transformers Quiz Questions And Answers

1.

The following Connection is a Delta Connection.
- A.
  
  True
- B.
  
  False
Correct Answer
A. True

Explanation
The given statement is true because a Delta Connection is a type of electrical connection used in three-phase systems. In this configuration, the three phases are connected in a triangular shape, resembling the Greek letter delta (Δ). This connection is commonly used in power distribution systems and provides a balanced load across all three phases.

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2.

The industrial use transformer that normally has 240v or 480v primary and a 120 v secondary is called a(n) ____ transformer.
- A.
  
  Auto
- B.
  
  Distribution
- C.
  
  Isolation
- D.
  
  Control
Correct Answer
D. Control

Explanation
The industrial use transformer that normally has a 240v or 480v primary and a 120v secondary is called a control transformer. Control transformers are commonly used in industrial applications to provide the necessary voltage for control circuits, such as motor control or lighting control. These transformers are designed to step down the high primary voltage to a lower secondary voltage, allowing for safe and efficient operation of control systems.

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3.

What is the best way to verify the connection of three single-phase transformers?
- A.
  
  With a growler
- B.
  
  With a megger
- C.
  
  With a voltmeter
- D.
  
  With ammeter
Correct Answer
B. With a megger

Explanation
The best way to verify the connection of three single-phase transformers is with a megger. A megger is a specialized instrument used to measure insulation resistance. By using a megger, we can check the insulation between the windings and the transformer's core. This helps ensure that there are no faults or issues with the transformer's connections, ensuring safe and efficient operation. A growler is used to detect faults in the windings, a voltmeter measures voltage, and an ammeter measures current, but neither of these options specifically verify the connection of the transformers.

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4.

An open delta connection is made using ____ single-phase transformers.
- A.
  
  One
- B.
  
  Two
- C.
  
  Three
- D.
  
  Four
Correct Answer
B. Two

Explanation
An open delta connection is made using two single-phase transformers. In an open delta configuration, two transformers are used to create a three-phase system. This is done by connecting two primary windings in parallel and one secondary winding in series. The open delta connection is used when one transformer fails, allowing the system to continue operating with reduced capacity. By using two single-phase transformers, the open delta connection provides a cost-effective solution for three-phase power distribution.

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5.

The following is a Delta connection.
- A.
  
  True
- B.
  
  False
Correct Answer
B. False

Explanation
The given statement is "The following is a Delta connection." The correct answer is False. This means that the following is not a Delta connection. However, without any additional context or information, it is not possible to provide a more specific explanation.

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6.

If a transformer fails one of the following tests, which test will indicate a complete transformer failure?
- A.
  
  Load test
- B.
  
  Non-load test
- C.
  
  Power factor
- D.
  
  Dielectric
Correct Answer
D. Dielectric

Explanation
The dielectric test is used to measure the insulation strength of a transformer. If a transformer fails this test, it indicates a complete failure of the insulation system, which is crucial for the safe and efficient operation of the transformer. The dielectric test checks for any breakdown or weakness in the insulation, which could lead to short circuits or other electrical faults. Therefore, if the transformer fails the dielectric test, it means that it cannot be used and needs to be replaced or repaired.

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7.

The magnetizing inrush current in a transformer is rich in:
- A.
  
  3rd harmonics
- B.
  
  5th harmonics
- C.
  
  7th harmonics
- D.
  
  2nd harmonics
Correct Answer
D. 2nd harmonics

Explanation
The magnetizing inrush current in a transformer is rich in 2nd harmonics. This means that when the transformer is energized, the current waveform contains a significant amount of harmonic energy at twice the fundamental frequency. This is due to the non-linear behavior of the transformer core during the magnetization process. The presence of 2nd harmonics in the inrush current can have implications for the design and protection of the transformer and the surrounding electrical system.

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8.

A transformer that does not isolate the output from the input is called a(n) ____ transformer.
- A.
  
  Distribution
- B.
  
  Auto
- C.
  
  Control
- D.
  
  Isolation
Correct Answer
B. Auto

Explanation
An auto transformer is a type of transformer that does not provide complete isolation between the input and output. Instead, it uses a single winding with taps at different points to step up or step down the voltage. This design allows for a more compact and efficient transformer, but it does not provide the same level of isolation as a traditional transformer with separate windings.

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9.

Two transformers are connected in parallel, one has twice the internal impedance of the other,
- A.
  
  The higher-impedance transformer will carry Jess than half the load of the lower-impedance transformer.
- B.
  
  The lower impedance transformer will carry more than twice as much load as the higher impedance transformer.
- C.
  
  The lower impedance transformer will overload.
- D.
  
  The higher impedance transformer will short circuit.
Correct Answer
C. The lower impedance transformer will overload.

Explanation
The lower impedance transformer will overload because it has a lower internal impedance, which means it has less resistance to the flow of current. As a result, it will carry more load than the higher impedance transformer, which can lead to an overload situation.

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10.

One winding of the transformer is short-circuited, and a voltmeter, ammeter, and wattmeter are connected in the circuit of the other winding. A small voltage is applied to and regulated to that values of current from 50% to 125% of the rated current of the winding are obtained. The above is part of the description for a test of a transformer:
- A.
  
  Exciting current
- B.
  
  Hysteresis
- C.
  
  Iron Loss
- D.
  
  Impedance
Correct Answer
D. Impedance

Explanation
The description states that a small voltage is applied and regulated to obtain current values ranging from 50% to 125% of the rated current. This indicates that the test is measuring the impedance of the transformer. Impedance is a measure of the opposition to the flow of current in an electrical circuit, and it is affected by factors such as resistance, inductance, and capacitance. By measuring the current at different voltage levels, the impedance of the transformer can be determined.

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Transformers Quiz Questions And Answers

The following Connection is a Delta Connection.

The industrial use transformer that normally has 240v or 480v primary and a 120 v secondary is called a(n) ____ transformer.

What is the best way to verify the connection of three single-phase transformers?

An open delta connection is made using ____ single-phase transformers.

The following is a Delta connection.

If a transformer fails one of the following tests, which test will indicate a complete transformer failure?

The magnetizing inrush current in a transformer is rich in:

A transformer that does not isolate the output from the input is called a(n) ____ transformer.

Two transformers are connected in parallel, one has twice the internal impedance of the other,