Electrical Machine - I (3140913) MCQs
MCQs of DC Machines
| 131. |
If the load current and the flux of a DC motor are held constant and the voltage applied across its armature is increased by 5%, the speed of the motor will
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Answer:
Option (b) |
| 132. |
The armature shaft must be able to withstand
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Answer:
Option (d) |
| 133. |
In a DC Shunt Motor if the load current increases keeping the terminal voltage constant, then flux will
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Answer:
Option (c) |
| 134. |
Which of the following DC Motor is used in paper machines?
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Answer:
Option (b) |
| 135. |
In electric locomotives which of the following motor are used ?
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Answer:
Option (a) |
| 136. |
For 250 volt DC Shunt Motor the armature and field resistance are 0.5 ohms and 250 ohms respectively. What will be the back e.m.f. produced when it takes a load current of 21A.
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Answer:
Option (c) |
| 137. |
The speed of a motor falls from 1100 r.p.m at no-load to 1050 r.p.m at rated load. The speed regulation of motor is
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Answer:
Option (d) |
| 138. |
A 250 volt dc series motor having an armature resistance of 0.2 Ω takes a load current of 60 A. What will be the torque produced at the shaft of the motor? Consider a brush drop of 1V.
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Answer:
Option (a) |
| 139. |
Two identical lossless series motors connected in series across a dc supply voltage and runs at speed of N1 and N2, then ratio of their output power is
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Answer:
Option (b) |
| 140. |
The number of brushes in a commutator depends on
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Answer:
Option (c) |
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