MCQOPTIONS
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MCQOPTIONS
This section includes 12 Mcqs, each offering curated multiple-choice questions to sharpen your Electric Drives knowledge and support exam preparation. Choose a topic below to get started.
| 1. |
Calculate the active power in an 8 resistor with 8 A current flowing through it. |
| A. | 512 W |
| B. | 514 W |
| C. | 512 W |
| D. | 518 W |
| Answer» B. 514 W | |
| 2. |
For a practical synchronous motor, the pull-out torque will occur when the torque angle is nearly equal to ________ |
| A. | 0 |
| B. | 30 |
| C. | 45 |
| D. | 75 |
| Answer» E. | |
| 3. |
A 3-phase induction motor runs at almost 1500 rpm at no load and 900 rpm at full load when supplied with power from a 50 Hz, 3-phase supply. What is the corresponding speed of the rotor field with respect to the rotor? |
| A. | 300 revolution per minute |
| B. | 400 revolution per minute |
| C. | 600 revolution per minute |
| D. | 500 revolution per minute |
| Answer» D. 500 revolution per minute | |
| 4. |
In an induction motor, when the number of stator slots is not equal to an integral number of rotor slots _________ |
| A. | There may be a discontinuity in torque slip characteristics |
| B. | A high starting torque will be available |
| C. | The machine performs better |
| D. | The machine may fail to start |
| Answer» D. The machine may fail to start | |
| 5. |
The slope of the V-I curve is 7 . Calculate the value of resistance. Assume the relationship between voltage and current is a straight line. |
| A. | .122 |
| B. | .360 |
| C. | .377 |
| D. | .578 |
| Answer» B. .360 | |
| 6. |
In a synchronous machine, the phase sequence can be reversed by reversing the _________ |
| A. | Rotor direction |
| B. | Field polarities |
| C. | Armature terminal |
| D. | Rotor direction and armature terminal |
| Answer» B. Field polarities | |
| 7. |
Which of the following are used in preventing the hunting phenomenon in synchronous generators? |
| A. | Damper bars |
| B. | Short pitch chords |
| C. | Distributed winding |
| D. | Damper bars and short pitch chords |
| Answer» B. Short pitch chords | |
| 8. |
The hunting phenomenon in a synchronous motor is also referred to as _________ |
| A. | Surging |
| B. | Phase swinging |
| C. | Cogging |
| D. | Surging and phase swinging |
| Answer» E. | |
| 9. |
The leakage flux paths are ________ on the angular position of the rotor. |
| A. | Dependent |
| B. | Proportional |
| C. | Independent |
| D. | Dependent and independent |
| Answer» D. Dependent and independent | |
| 10. |
Calculate the phase angle of the sinusoidal waveform z(t)=8cos(45t+2 15). |
| A. | 2 39 |
| B. | 2 15 |
| C. | 4 |
| D. | 2 44 |
| Answer» C. 4 | |
| 11. |
A 4-pole, 3-phase, 60 Hz induction motor is operating at a speed of 1500 rpm. The frequency of the rotor current of the motor in Hz is __________ |
| A. | 5 |
| B. | 4 |
| C. | 2 |
| D. | 7 |
| Answer» C. 2 | |
| 12. |
The direct axis is taken along ________ |
| A. | Inter-polar axis |
| B. | Rotor pole axis |
| C. | In between inter polar and rotor axis |
| D. | Parallel to interpolar axis |
| Answer» C. In between inter polar and rotor axis | |