Transformer Maintenance Quiz
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Questions and Answers

What is the primary function of an oil conservator in a transformer?

  • To facilitate the filling and draining of oil
  • To allow for gas detection during operation
  • To increase the oil level at high temperatures
  • To maintain a constant oil level and minimize air contact (correct)

    • Which method is considered more efficient for cooling larger transformers?

  • Radiator cooling
  • Air cooling
  • Water cooling
  • Oil cooling (correct)

    • What role do pressure relief devices play in transformer tanks?

  • They facilitate the filling process of the oil tank
  • They monitor the oil quality and purity
  • They enhance oil circulation within the tank
  • They prevent internal pressure from becoming excessive (correct)

    • What must be determined first when calculating the cooling tubes for a transformer?

    <p>Total heat load generated by the transformer</p> Signup and view all the answers

    What is the main purpose of using gaskets and seals in transformer tanks?

    <p>To maintain the tank's airtightness and prevent leaks</p> Signup and view all the answers

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

    <p>To receive electrical power from the source</p> Signup and view all the answers

    How does the number of turns in the secondary winding affect a transformer?

    <p>It affects the voltage transformation ratio</p> Signup and view all the answers

    What distinguishes a three-phase transformer from a single-phase transformer?

    <p>It has three primary and three secondary windings</p> Signup and view all the answers

    In which situation would an auto-transformer be preferred over a conventional transformer?

    <p>When compact size and cost-effectiveness are essential</p> Signup and view all the answers

    What is the main advantage of using concentric winding arrangements in transformers?

    <p>Provides better insulation and compact design</p> Signup and view all the answers

    What is the typical characteristic of high-voltage windings compared to low-voltage windings in transformers?

    <p>High-voltage windings usually have fewer turns than low-voltage windings</p> Signup and view all the answers

    What material is often chosen for windings due to its high conductivity?

    <p>Copper</p> Signup and view all the answers

    What is a disadvantage of using aluminum windings in transformers compared to copper windings?

    <p>Lower conductivity than copper windings</p> Signup and view all the answers

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

    <p>To generate a magnetic field when AC flows through it.</p> Signup and view all the answers

    What factors need to be considered when designing a transformer?

    <p>Core material, insulation, and winding design.</p> Signup and view all the answers

    How is the turns ratio of a transformer calculated?

    <p>By determining the desired output voltage relative to the primary voltage.</p> Signup and view all the answers

    What does the no-load current in a transformer primarily represent?

    <p>The inductive current needed to establish a magnetic field.</p> Signup and view all the answers

    Which material is often used for the transformer core?

    <p>Silicon steel</p> Signup and view all the answers

    What does the magnetizing reactance (Xm) in a transformer correlate with?

    <p>The voltage divided by the no-load current.</p> Signup and view all the answers

    In a star (Wye) connection, how are the transformer windings arranged?

    <p>In a Y shape.</p> Signup and view all the answers

    What measure can be taken to assess the no-load current directly?

    <p>Using a current meter on the primary winding with the secondary open-circuited.</p> Signup and view all the answers

    What is the main purpose of the magnetic core in a transformer?

    <p>To enhance magnetic coupling between windings.</p> Signup and view all the answers

    What type of stress is primarily caused by heating and cooling cycles in a transformer?

    <p>Thermal stress</p> Signup and view all the answers

    Which cooling method enhances the heat dissipation rate by using natural convection and forced air?

    <p>Oil Natural Air Forced (ONAF) Cooling</p> Signup and view all the answers

    How does the transformer inrush current affect the transformer?

    <p>It can create transient electromagnetic forces.</p> Signup and view all the answers

    What is the primary material used in the construction of a transformer tank?

    <p>Steel</p> Signup and view all the answers

    Which cooling method specifically utilizes water to enhance cooling efficiency?

    <p>Oil Forced Water (OFW) Cooling</p> Signup and view all the answers

    What structural feature is added to a transformer tank to improve heat dissipation?

    <p>Fins</p> Signup and view all the answers

    Which component is crucial for detecting issues within the transformer tank?

    <p>Buchholz relay</p> Signup and view all the answers

    What is one consequence of core saturation in a transformer?

    <p>Decreased efficiency</p> Signup and view all the answers

    Which type of fault current can lead to significant electromagnetic forces within a transformer?

    <p>Fault current</p> Signup and view all the answers

    What primary function does transformer oil serve in oil-immersed cooling?

    <p>To provide electrical insulating properties</p> Signup and view all the answers

    What does the turns ratio of a transformer indicate?

    <p>The ratio of voltage transformation between primary and secondary.</p> Signup and view all the answers

    How is the current relationship between the primary and secondary winding expressed?

    <p>I_1/I_2 = N_2/N_1</p> Signup and view all the answers

    What is the effect of leakage flux in transformers?

    <p>It causes voltage drops in the windings.</p> Signup and view all the answers

    What does the voltage transformation ratio (K) signify in a transformer?

    <p>The ratio of induced emf in the primary to that in the secondary.</p> Signup and view all the answers

    In which situation is a transformer classified as a step-up transformer?

    <p>When N2 &gt; N1.</p> Signup and view all the answers

    What factors primarily affect the efficiency of energy transfer in a transformer?

    <p>The design of the windings and the magnetic core.</p> Signup and view all the answers

    How is the RMS value of induced emf per turn calculated?

    <p>Using the formula 4.44fFm.</p> Signup and view all the answers

    What type of forces act along the length of the winding in a transformer?

    <p>Axial Forces.</p> Signup and view all the answers

    Which of the following is NOT a function of transformers?

    <p>Converting AC to DC voltage.</p> Signup and view all the answers

    What is the typical consequence of having leakage reactance in a transformer?

    <p>Voltage drops in windings.</p> Signup and view all the answers

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