MCQOPTIONS
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MCQOPTIONS
This section includes 9 Mcqs, each offering curated multiple-choice questions to sharpen your Dc Machines knowledge and support exam preparation. Choose a topic below to get started.
| 1. |
What is the value of pole pitch (in SI unit) for mean air gap radius= 0.5mm and P=4? |
| A. | 0.785* 10-6 |
| B. | 0.785* 10-3 |
| C. | 0.785* 10-2 |
| D. | 0.785* 10-4 |
| Answer» C. 0.785* 10-2 | |
| 2. |
What is the value of Np in an average coil emf equation, for 10 armature conductors with 2 parallel paths?a) 2b) 3c) 2.5d) 4 9.What is the torque equation in terms of B, Ic, l, Zr (r= mean air gap radius)? |
| A. | 2b) 3c) 2.5d) 4 9.What is the torque equation in terms of B, Ic, l, Zr (r= mean air gap radius)?a) Bav*Ic*l*Zr |
| B. | 3c) 2.5d) 4 9.What is the torque equation in terms of B, Ic, l, Zr (r= mean air gap radius)?a) Bav*Ic*l*Zrb) Bav*Ic*l/Zr |
| C. | 2.5d) 4 9.What is the torque equation in terms of B, Ic, l, Zr (r= mean air gap radius)?a) Bav*Ic*l*Zrb) Bav*Ic*l/Zrc) Bav*Ic*Zr/l |
| D. | 4 9.What is the torque equation in terms of B, Ic, l, Zr (r= mean air gap radius)?a) Bav*Ic*l*Zrb) Bav*Ic*l/Zrc) Bav*Ic*Zr/ld) Can’t be expressedView Answer |
| Answer» D. 4 9.What is the torque equation in terms of B, Ic, l, Zr (r= mean air gap radius)?a) Bav*Ic*l*Zrb) Bav*Ic*l/Zrc) Bav*Ic*Zr/ld) Can’t be expressedView Answer | |
| 3. |
Emf and torque produced in a DC machine are proportional to ________ and _________ respectively. |
| A. | Armature speed and armature emf |
| B. | Armature emf and armature speed |
| C. | Armature current and armature emf |
| D. | Armature speed and armature current |
| Answer» E. | |
| 4. |
What is the average coil emf generated in a 4-pole DC machine having flux/pole equal to 0.1 wb rotating at 1500 rpm? (No. of coil sides = 100) |
| A. | 19 kV |
| B. | 1.9 kV |
| C. | 190 V |
| D. | 19 V |
| Answer» B. 1.9 kV | |
| 5. |
Average coil emf for 20 coil turns (E1) and 40 coil turns (E2), will have ratio E1/E2=____ (assuming all other parameters same for both machines). |
| A. | 1/2 |
| B. | 2/1 |
| C. | 1/4 |
| D. | 4/1 |
| Answer» B. 2/1 | |
| 6. |
Emf produced by DC machine, for zero armature current (E1) and non-zero armature current (E2) can be related as__________ |
| A. | E1 = E2 |
| B. | E1 > E2 |
| C. | E1 < E2 |
| D. | Can’t be determined |
| Answer» B. E1 > E2 | |
| 7. |
In a DC machine, average energy stored in the magnetic field remains constant independent of the armature rotation. |
| A. | True |
| B. | False |
| Answer» B. False | |
| 8. |
Nature of the flux density wave in the air gap is__________ (for armature current equal to 0) |
| A. | Flat topped with quarter wave symmetry |
| B. | Point topped with quarter wave symmetry |
| C. | Flat topped with half wave symmetry |
| D. | Point topped with half wave symmetry |
| Answer» B. Point topped with quarter wave symmetry | |
| 9. |
In which mode machine is operating, given that conductor current is in the same direction of conductor emf? |
| A. | Motoring |
| B. | Generating |
| C. | Can’t be determined using directions |
| D. | In both modes for different cycles |
| Answer» C. Can’t be determined using directions | |