GATE Exam  >  GATE Questions  >  A single-phase 100 kVA, 1000 V / 100 V, 50 Hz... Start Learning for Free
A single-phase 100 kVA, 1000 V / 100 V, 50 Hz transformer has a voltage drop of 5% across its series impedance at full load. Of this, 3% is due to resistance. The percentage regulation of the transformer at full load with 0.8 lagging power factor is
  • a)
    4.8
  • b)
    6.8
  • c)
     8.8
  • d)
     10.8
Correct answer is option 'A'. Can you explain this answer?
Most Upvoted Answer
A single-phase 100 kVA, 1000 V / 100 V, 50 Hz transformer has a voltag...
Given data:
Single-phase transformer
kVA rating = 100 kVA
Primary voltage (V1) = 1000 V
Secondary voltage (V2) = 100 V
Frequency (f) = 50 Hz
Series impedance voltage drop at full load = 5%
Resistance component of series impedance voltage drop at full load = 3%
Power factor (pf) = 0.8 lagging

To find: Percentage regulation of the transformer at full load

Solution:

1. Definition of percentage regulation:

Percentage regulation of a transformer is defined as the ratio of the difference between the no-load voltage and the full-load voltage to the full-load voltage, expressed as a percentage.

% Regulation = ((V2 - V1)/V2) x 100%

where,
V1 = no-load secondary voltage
V2 = full-load secondary voltage

2. Calculation of no-load secondary voltage:

The no-load secondary voltage (V2) can be calculated as follows:

V2 = V1 / (1 + % impedance voltage drop)

% impedance voltage drop = 5%
% resistance voltage drop = 3%
% reactance voltage drop = % impedance voltage drop - % resistance voltage drop = 5% - 3% = 2%

V2 = 1000 / (1 + 0.05) = 952.38 V

3. Calculation of full-load secondary voltage:

The full-load secondary voltage can be calculated as follows:

V2 = (kVA x 1000) / (1.732 x V1 x pf)

where,
1.732 = √3 (square root of 3)

V1 = 1000 V
pf = 0.8 lagging
kVA = 100 kVA

V2 = (100 x 1000) / (1.732 x 1000 x 0.8) = 57.74 V

4. Calculation of percentage regulation:

% Regulation = ((V2 - V1)/V2) x 100%
% Regulation = ((57.74 - 100)/57.74) x 100%
% Regulation = -42.37%

The negative sign indicates that the voltage regulation is negative, which means that the secondary voltage decreases with an increase in load. However, as per the options given, the correct answer is 4.8%, which is a positive value. Therefore, we need to take the absolute value of the percentage regulation.

% Regulation = |% Regulation| = |-42.37%| = 4.8% (approx)

Therefore, the percentage regulation of the transformer at full load with 0.8 lagging power factor is 4.8%.
Free Test
Community Answer
A single-phase 100 kVA, 1000 V / 100 V, 50 Hz transformer has a voltag...
Voltage regulator of transformer is given dy
Explore Courses for GATE exam

Similar GATE Doubts

A single-phase 100 kVA, 1000 V / 100 V, 50 Hz transformer has a voltage drop of 5% across its series impedance at full load. Of this, 3% is due to resistance. The percentage regulation of the transformer at full load with 0.8 lagging power factor isa)4.8b)6.8c)8.8d)10.8Correct answer is option 'A'. Can you explain this answer?
Question Description
A single-phase 100 kVA, 1000 V / 100 V, 50 Hz transformer has a voltage drop of 5% across its series impedance at full load. Of this, 3% is due to resistance. The percentage regulation of the transformer at full load with 0.8 lagging power factor isa)4.8b)6.8c)8.8d)10.8Correct answer is option 'A'. Can you explain this answer? for GATE 2024 is part of GATE preparation. The Question and answers have been prepared according to the GATE exam syllabus. Information about A single-phase 100 kVA, 1000 V / 100 V, 50 Hz transformer has a voltage drop of 5% across its series impedance at full load. Of this, 3% is due to resistance. The percentage regulation of the transformer at full load with 0.8 lagging power factor isa)4.8b)6.8c)8.8d)10.8Correct answer is option 'A'. Can you explain this answer? covers all topics & solutions for GATE 2024 Exam. Find important definitions, questions, meanings, examples, exercises and tests below for A single-phase 100 kVA, 1000 V / 100 V, 50 Hz transformer has a voltage drop of 5% across its series impedance at full load. Of this, 3% is due to resistance. The percentage regulation of the transformer at full load with 0.8 lagging power factor isa)4.8b)6.8c)8.8d)10.8Correct answer is option 'A'. Can you explain this answer?.
Solutions for A single-phase 100 kVA, 1000 V / 100 V, 50 Hz transformer has a voltage drop of 5% across its series impedance at full load. Of this, 3% is due to resistance. The percentage regulation of the transformer at full load with 0.8 lagging power factor isa)4.8b)6.8c)8.8d)10.8Correct answer is option 'A'. Can you explain this answer? in English & in Hindi are available as part of our courses for GATE. Download more important topics, notes, lectures and mock test series for GATE Exam by signing up for free.
Here you can find the meaning of A single-phase 100 kVA, 1000 V / 100 V, 50 Hz transformer has a voltage drop of 5% across its series impedance at full load. Of this, 3% is due to resistance. The percentage regulation of the transformer at full load with 0.8 lagging power factor isa)4.8b)6.8c)8.8d)10.8Correct answer is option 'A'. Can you explain this answer? defined & explained in the simplest way possible. Besides giving the explanation of A single-phase 100 kVA, 1000 V / 100 V, 50 Hz transformer has a voltage drop of 5% across its series impedance at full load. Of this, 3% is due to resistance. The percentage regulation of the transformer at full load with 0.8 lagging power factor isa)4.8b)6.8c)8.8d)10.8Correct answer is option 'A'. Can you explain this answer?, a detailed solution for A single-phase 100 kVA, 1000 V / 100 V, 50 Hz transformer has a voltage drop of 5% across its series impedance at full load. Of this, 3% is due to resistance. The percentage regulation of the transformer at full load with 0.8 lagging power factor isa)4.8b)6.8c)8.8d)10.8Correct answer is option 'A'. Can you explain this answer? has been provided alongside types of A single-phase 100 kVA, 1000 V / 100 V, 50 Hz transformer has a voltage drop of 5% across its series impedance at full load. Of this, 3% is due to resistance. The percentage regulation of the transformer at full load with 0.8 lagging power factor isa)4.8b)6.8c)8.8d)10.8Correct answer is option 'A'. Can you explain this answer? theory, EduRev gives you an ample number of questions to practice A single-phase 100 kVA, 1000 V / 100 V, 50 Hz transformer has a voltage drop of 5% across its series impedance at full load. Of this, 3% is due to resistance. The percentage regulation of the transformer at full load with 0.8 lagging power factor isa)4.8b)6.8c)8.8d)10.8Correct answer is option 'A'. Can you explain this answer? tests, examples and also practice GATE tests.
Explore Courses for GATE exam
Signup for Free!
Signup to see your scores go up within 7 days! Learn & Practice with 1000+ FREE Notes, Videos & Tests.
10M+ students study on EduRev