MCQOPTIONS
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MCQOPTIONS
This section includes 9 Mcqs, each offering curated multiple-choice questions to sharpen your Power Electronics knowledge and support exam preparation. Choose a topic below to get started.
| 1. |
In a 3-phase semi-converter, for firing angle less than 60° the freewheeling diode conducts for |
| A. | 30° |
| B. | 60° |
| C. | 120° |
| D. | 0 |
| Answer» E. | |
| 2. |
A three-phase semi-converter circuit is given a supply of 400 V. It produces at the output terminals an average voltage of 381 V. Find the rectification efficiency of the converter circuit. |
| A. | 99.65 % |
| B. | 95.25 % |
| C. | 91 % |
| D. | 86.5 % |
| Answer» C. 91 % | |
| 3. |
A 3-phase full converter feeds power to an R load of 10 Ω. For a firing angle delay of 30° the load takes 5 kW. An inductor of large value is also connected to the load to make the current ripple free. Find the value of per phase input voltage. |
| A. | 133 V |
| B. | 230/√3 V |
| C. | 191/√3 V |
| D. | 298/√3 V |
| Answer» D. 298/√3 V | |
| 4. |
What is the value of voltage at the output terminal when the freewheeling diode (FD) is conducting? |
| A. | Zero |
| B. | Maximum |
| C. | E |
| D. | It could be anything depending on α |
| Answer» B. Maximum | |
| 5. |
In a three-phase semi-converter, at a time one SCR and one diode conduct simultaneously. With SCR T1 conducting which diode(s) is most likely to conduct along with T1? |
| A. | D2 only |
| B. | D3 only |
| C. | D1 and D2 |
| D. | D2 and D3 |
| Answer» E. | |
| 6. |
In the below given circuit, __ and __ conduct along with T2. |
| A. | T1, T3 |
| B. | D1, D2 |
| C. | D1, D3 |
| D. | T1, T2 |
| Answer» D. T1, T2 | |
| 7. |
In the below given circuit, each SCR and diode conduct for |
| A. | 60° and 120° respectively |
| B. | 120° and 60° respectively |
| C. | 120° |
| D. | 60° |
| Answer» D. 60° | |
| 8. |
A three-phase full converter is driving a DC motor. If a continues current of Im amperes is flowing through the motor load, then find the rms value of supply current drawn by the converter to drive the motor. |
| A. | Im/√2 |
| B. | Im2/3 |
| C. | √2Im/√3 |
| D. | √2Im/3 |
| Answer» D. √2Im/3 | |
| 9. |
A three-phase full converter supplied from a 230 V source is working as a line commutated inverter. The load consists of RLE type with R = 5 Ω, E = 200 V and L = 1 mH. A continues current of 10 A is flowing through the load, find the value of the firing angle delay. |
| A. | 119° |
| B. | 127° |
| C. | 156° |
| D. | 143° |
| Answer» B. 127° | |