Podcast
Questions and Answers
The percentage impedance (Z%) of a transformer is the voltage drop expressed as a percentage of the rated primary voltage when full load current flows in the primary and secondary windings with a short connected across the secondary terminals.
The percentage impedance (Z%) of a transformer is the voltage drop expressed as a percentage of the rated primary voltage when full load current flows in the primary and secondary windings with a short connected across the secondary terminals.
True (A)
To measure impedance, the primary winding of the transformer is short circuited and measuring instruments are connected to measure the primary voltage at full load current.
To measure impedance, the primary winding of the transformer is short circuited and measuring instruments are connected to measure the primary voltage at full load current.
False (B)
Identify the correct order of the following steps to measure impedance.
Identify the correct order of the following steps to measure impedance.
- The secondary winding of the transformer is short circuited and measuring instruments connected. (correct)
- Readings on the voltmeter and ammeter are noted. (correct)
- The applied voltage is adjusted until the transformer under test is carrying its rated full-load current. (correct)
- % impedance calculations are carried out using the values obtained during testing. (correct)
Calculate the impedance percentage (Z%) of a transformer with a measured impedance voltage of 82 V on a 3,000/240V transformer.
Calculate the impedance percentage (Z%) of a transformer with a measured impedance voltage of 82 V on a 3,000/240V transformer.
Study Notes
Percentage Impedance in Transformers
- Percentage impedance (Z%) of a transformer reflects the voltage drop when full load current flows and the secondary is short-circuited.
- Accurate determination involves short-circuiting the secondary winding rather than the primary.
Measurement Process
- The correct procedure to measure impedance involves:
- Short-circuiting the secondary winding.
- Adjusting applied voltage until the rated full-load current is reached.
- Noting voltmeter and ammeter readings.
- Calculating % impedance using the measured values.
Calculation Example
- Calculation for a 3,000/240V transformer:
- Measured impedance voltage is 82 V on high voltage windings.
- Correct Z% calculated as 2.73%.
Assessment Performance
- Assessment successfully completed with a score of 100%.
- Provided feedback emphasizes successful understanding and good luck for continued studies.
Studying That Suits You
Use AI to generate personalized quizzes and flashcards to suit your learning preferences.
Related Documents
Description
Test your understanding of percentage impedance in transformers with this targeted assessment. This quiz covers key concepts and problem-solving techniques relevant to your studies in electrical engineering. Achieve a perfect score and validate your knowledge!
