Power Electronics - Section 1 (6)
Power Electronics - Section 1
| 41. | In a single phase full wave converter (M - 2 connection) feeding a highly inductive load, the firing angle for each thyristor is a in the respective half cycle. The period of conduction of each thyristor is |
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Answer: Option B Explanation: Since conduction is from a to p + a, period of conduction is p in each half cycle. |
| 42. | For a 12 pulse operation, the two 6 pulse units are fed by |
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Answer: Option C Explanation: 30° phase difference is necessary. |
| 43. | A thyristor has a maximum allowable junction temperature of 120°C and the ambient temperature is 40°C. If thermal resistance is 1.6° C/W, the maximum allowable internal power dissipation is |
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| 44. | The phenomenon of overlap in converter operation due to |
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Answer: Option B Explanation: Source inductance delays turn off and hence causes overlap. |
| 45. | A semiconverter feeding an RLE load operates in |
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Answer: Option A Explanation: Semiconvertor operates only in first quadrant. |
| 46. | The amount of dielectric heating is inversely proportional to frequency. |
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Answer: Option B Explanation: It is proportional to frequency. |
| 47. | Two thyristor of same rating and same specifications |
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Answer: Option C Explanation: Turn on and turn off times of similar SCRs may not be same. |
| 48. | In a 3 phase fully controlled converter the firing frequency is |
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Answer: Option B Explanation: It is a 6 pulse converter. |