MCQOPTIONS
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MCQOPTIONS
This section includes 8 Mcqs, each offering curated multiple-choice questions to sharpen your Electrical Machines knowledge and support exam preparation. Choose a topic below to get started.
| 1. |
In the lab, two students X and Y conducted the experiments to verify the name plate ratings of the transformer.But student X conducted the same at higher frequency. The kVA reading of student X will be ___________ |
| A. | higher than Y s reading |
| B. | lower than Y s reading |
| C. | same as Y s reading |
| D. | none of the mentioned |
| Answer» B. lower than Y s reading | |
| 2. |
Auto transformer rating is chosen so as to have best performance when the analogous two winding transformer has ___________ |
| A. | two voltage levels fairly close to each other |
| B. | very high transformation ratio |
| C. | any voltage levels |
| D. | step down purpose |
| Answer» B. very high transformation ratio | |
| 3. |
A 200V, 10 hp, 4 poles, 60 Hz, Y-connected induction motor had full load slip of 5%. Then the rotor speed of the motor with respect to stator is? |
| A. | 1710 rpm |
| B. | 1800 rpm |
| C. | 90 rpm |
| D. | 3510 rpm |
| Answer» B. 1800 rpm | |
| 4. |
For a separately excited dc machine of 25 kW, 250 V and armature resistance of 0.25 ohms, is running at 3000 rpm with supply of 255 V. The electromagnetic power produced at the armature in kilo watts is? |
| A. | 5 |
| B. | 10 |
| C. | 0.5 |
| D. | 8 |
| Answer» B. 10 | |
| 5. |
A 3-phase, five limbed shell type transformer, star connected, 200V, 50 Hz, 100 kVA will have ___________ |
| A. | no third harmonic current in its phase but has sinusoidal flux |
| B. | third harmonic current in its phase but has flat-topped flux |
| C. | no third harmonic current in its phase but has flat-topped flux |
| D. | third harmonic current in its phase but has sinusoidal flux |
| Answer» B. third harmonic current in its phase but has flat-topped flux | |
| 6. |
While conducting lab experiments on DC machine loading, the students are given a machine with its rating as 100 kW maximum rating. Then the _____________ |
| A. | machine can t be overloaded after 100 kW |
| B. | machine can be overloaded after 100 kW |
| C. | machine can be overloaded by 5% for a small time duration |
| D. | machine can be overloaded by 10% |
| Answer» B. machine can be overloaded after 100 kW | |
| 7. |
The desired voltage regulation for a single phase, 50 Hz transformer is zero. Its pu ohmic drop is 4% and pu reactive drop is 4%. The required power factor angle for the operation in degrees is? |
| A. | 45 |
| B. | 90 |
| C. | 30 |
| D. | 60 |
| Answer» B. 90 | |
| 8. |
If the dimension of a single phase transformer is made sqrt(3) times less than the original structure, then what is new no load current rating of the transformer? |
| A. | 1/sqrt(3) |
| B. | sqrt(3) |
| C. | 3 |
| D. | 1/3*sqrt(3) |
| Answer» B. sqrt(3) | |