MCQOPTIONS
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MCQOPTIONS
This section includes 14 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. |
A shunt generator has an induced voltage on open circuit of 127 V. When the machine is on load the terminal voltage is 120 V. The load current if the field resistance be 15 ohm and armature resistance be 15 ohm. |
| A. | 342 A |
| B. | 350 A |
| C. | 358 A |
| D. | 8 A |
| Answer» B. 350 A | |
| 2. |
If the DC machine is held constant at 3000 rpm. The DC voltage is 250V. If the field is held constant with 250V. Is this machine generator or motor? |
| A. | Motor |
| B. | Generator |
| C. | None of the mentioned |
| D. | Any of the mentioned |
| Answer» B. Generator | |
| 3. |
Consider a 200V, 25kW, 30A DC machine lap connected with armature resistance of 0.4 ohms. If the machine is later wave wound, then the developed power is? |
| A. | 25 kW |
| B. | 12.5 kW |
| C. | 20 kW |
| D. | 50 kW |
| Answer» B. 12.5 kW | |
| 4. |
What is the shaft power at the DC Generator? |
| A. | sum of mechanical power and rotational losses |
| B. | only mechanical losses |
| C. | no-load losses and mechanical power |
| D. | any of the mentioned |
| Answer» B. only mechanical losses | |
| 5. |
If the terminal voltage of 220-V dc generator having armature resistance of 1 ohms. The induced emf produced is 200-V. The armature current for the above machine is? |
| A. | 20 A |
| B. | -20 A |
| C. | -10 A |
| D. | 10 A |
| Answer» B. -20 A | |
| 6. |
IF_THE_DC_MACHINE_IS_HELD_CONSTANT_AT_3000_RPM._THE_DC_VOLTAGE_IS_250V._IF_THE_FIELD_IS_HELD_CONSTANT_WITH_250V._IS_THIS_MACHINE_GENERATOR_OR_MOTOR??$ |
| A. | Motor |
| B. | Generator |
| C. | None of the mentioned |
| D. | Any of the mentioned |
| Answer» B. Generator | |
| 7. |
A shunt generator has an induced voltage on open circuit of 127 V. When the machine is on load the terminal voltage is 120 V. The load current if the field resistance be 15 ohm and armature resistance be 15 ohm$ |
| A. | 342 A |
| B. | 350 A |
| C. | 358 A |
| D. | 8 A |
| Answer» B. 350 A | |
| 8. |
Consider a 200V, 25kW, 30A DC machine lap connected with armature resistance of 0.4 ohms. If the machine is later wave wound, then the developed power i? |
| A. | 25 kW |
| B. | 12.5 kW |
| C. | 20 kW |
| D. | 50 kW |
| Answer» B. 12.5 kW | |
| 9. |
If the armature terminal voltage is more that its induced EMF, the DC machine given i? |
| A. | motoring mode |
| B. | generating mode |
| C. | regenerative mode |
| D. | none of the mentioned |
| Answer» B. generating mode | |
| 10. |
The conductor EMF and current are in _____ direction and developed torque is in _____ for generating mode. |
| A. | same, opposite |
| B. | same,same |
| C. | opposite, same |
| D. | opposite, opposite |
| Answer» B. same,same | |
| 11. |
If the electromagnetic torque in a DC shunt-generator is opposite, what can be further concluded? |
| A. | Mechanical power is absorbed by the machine |
| B. | Mechanical power is delivered by the machine |
| C. | Electromagnetic torque is in same direction of prime mover |
| D. | None of the mentioned |
| Answer» B. Mechanical power is delivered by the machine | |
| 12. |
The shaft power at the DC Generator is |
| A. | sum of mechanical power and rotational losses |
| B. | only mechanical losses |
| C. | no-load losses and mechanical power |
| D. | any of the mentioned |
| Answer» B. only mechanical losses | |
| 13. |
The voltage drop at brush-commutator contact is variable (1-2V) and dependent of armature current. |
| A. | True |
| B. | False |
| Answer» C. | |
| 14. |
If the terminal voltage of 220-V dc generator having armature resistance of 1 ohms. The induced emf produced is 200-V. The armature current for the above machine is |
| A. | 20 A |
| B. | -20 A |
| C. | -10 A |
| D. | 10 A |
| Answer» B. -20 A | |