Discussion
A three-phase full wave controlled rectifier is operated from a three-phase star connected 208 V, 50 Hz supply and the load resistance is \(100\ \Omega\). What is the value of delay angle if it is required to obtain an average output voltage of 50% of the maximum possible output?
Answer: B
For a three phase full controlled (six pulse) bridge converter the average output voltage is \(V_{dc} = V_{dc,max}\cos\alpha\), where \(V_{dc,max}\) is the value at \(\alpha = 0\).
For an average output of 50 per cent of the maximum
\[ \cos\alpha = 0.5 \Rightarrow \alpha = 60^\circ \]
The supply voltage and the load resistance do not matter for the delay angle, since only the ratio matters. The angle \(30^\circ\) would give 86.6 per cent, \(45^\circ\) about 70.7 per cent and \(75^\circ\) about 25.9 per cent. The answer is \(60^\circ\), option B.
Post your comment
Please log in or register to post a comment.
Examination Categories
- SSC Exams
- Banking Exams
- Teaching Exams
- Civil Services Exams
- Railways Exams
- Engineering Recruitment Exams
- Defence Exams
- State Government Exams
- Police Exams
- Insurance Exams
- Nursing Exams
- Other Government Exams
- NRA CET
- PG Entrance Exams
- Campus Placement
- MBA Entrance Exams
- CUET and UG Entrance
- Judiciary Exams
- Regulatory Body Exams
- Software Development