MCQOPTIONS

Explore topic-wise MCQs in Dc Machines.

This section includes 18 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.	By changing the polarity of the armature of failed self-exciting machine, machine can be started.
A.	True
B.	False
Answer» B. False

2.	Which of the following is not a reason, behind failing of self-exciting machine?
A.	Residual magnetism is absent
B.	Negative feedback
C.	Field resistance value is more than critical resistance value
D.	Armature resistance is non-zero
Answer» E.

3.	DC generator will not self-excite in __________
A.	Positive feedback
B.	Negative feedback
C.	Zero Feedback
D.	Doesn’t depend on feedback
Answer» C. Zero Feedback

4.	No-load voltage can’t be defined where _____________
A.	Field resistance line lies below the magnetization linear line
B.	Field resistance line intersects the magnetization linear line
C.	Field resistance line coincides the magnetization linear line
D.	Defined everywhere
Answer» D. Defined everywhere

5.	For a self-excited DC shunt generator Ia = _____________
A.	IL – If
B.	IL + IL
C.	– IL – IL
D.	– IL + IL
Answer» C. – IL – IL

6.	DC_GENERATOR_WILL_NOT_SELF-EXCITE_IN___________?$
A.	Positive feedback
B.	Negative feedback
C.	Zero Feedback
D.	Doesn‚Äö√Ñ√∂‚àö√ë‚àö¬•t depend on feedback
Answer» C. Zero Feedback

7.	By changing the polarity of the armature of failed self-exciting machine, machine can be started.$
A.	True
B.	False
Answer» B. False

8.	Which of the following is not a reason, behind failing of self-exciting machine?$
A.	Residual magnetism is absent
B.	Negative feedback
C.	Field resistance value is more than critical resistance value
D.	Armature resistance is non-zero
Answer» E.

9.	Which of the following will be useful to generate positive feedback?
A.	Increasing the field resistance
B.	Increasing the armature resistance
C.	Decreasing the armature resistance
D.	Changing the shaft direction
Answer» E.

10.	No-load voltage observed at two different field resistance values, is V1 < V2. What will be the relation in speed if field resistance is kept same for both cases?
A.	N<sub>1</sub> < N<sub>2</sub>
B.	N<sub>1</sub> = N<sub>1</sub>
C.	N<sub>1</sub> > N<sub>1</sub>
D.	Can‚Äö√Ñ√∂‚àö√ë‚àö¬•t determine from no-load voltage
Answer» B. N<sub>1</sub> = N<sub>1</sub>

11.	No-load voltage observed at two different field resistance values, is V1 < V2. What will be the relation in field resistance values?
A.	Rf<sub>1</sub> < Rf<sub>2</sub>
B.	Rf<sub>1</sub> = Rf<sub>1</sub>
C.	Rf<sub>1</sub> > Rf<sub>1</sub>
D.	Can‚Äö√Ñ√∂‚àö√ë‚àö¬•t determine from no-load voltage
Answer» D. Can‚Äö√Ñ√∂‚àö√ë‚àö¬•t determine from no-load voltage

12.	Machine does not excite to an appreciable value when ___________
A.	Field resistance is less than critical resistance
B.	Field resistance is more than critical resistance
C.	In both cases a and b
D.	Depends on other parameters
Answer» C. In both cases a and b

13.	No-load voltage can‚Äö√Ñ√∂‚àö√ë‚àö¬•t be defined where _____________$
A.	Field resistance line lies below the magnetization linear line
B.	Field resistance line intersects the magnetization linear line
C.	Field resistance line coincides the magnetization linear line
D.	Defined everywhere
Answer» D. Defined everywhere

14.	What will happen if field resistance is decreased?
A.	No load voltage will decrease
B.	No load voltage will increase
C.	No change in no load voltage
D.	Field current will decrease
Answer» C. No change in no load voltage

15.	Intersection of Rf line and magnetization curve will give _____________
A.	No load terminal voltage
B.	Field current at no load
C.	Both a and b
D.	Not specific data
Answer» D. Not specific data

16.	For self-excited DC generator, field circuit curve in the OCC will be __________
A.	Straight line not passing through the origin with +ve slope
B.	Straight line passing through the origin
C.	Straight line not passing through the origin with -ve slope
D.	Increasing curve
Answer» C. Straight line not passing through the origin with -ve slope

17.	For a self-excited DC shunt generator Ia = _____________
A.	I<sub>L</sub> ‚Äö√Ñ√∂‚àö√ë‚àö¬® I<sub>f</sub>
B.	I<sub>L</sub> + I<sub>L</sub>
C.	‚Äö√Ñ√∂‚àö√ë‚àö¬® I<sub>L</sub> ‚Äö√Ñ√∂‚àö√ë‚àö¬® I<sub>L</sub>
D.	‚Äö√Ñ√∂‚àö√ë‚àö¬® I<sub>L</sub> + I<sub>L</sub>
Answer» C. ‚Äö√Ñ√∂‚àö√ë‚àö¬® I<sub>L</sub> ‚Äö√Ñ√∂‚àö√ë‚àö¬® I<sub>L</sub>

18.	What is Self-excitation in DC shunt generator?
A.	Field winding is connected in series of armature
B.	Field winding is connected in parallel of armature
C.	Field winding is not connected to the armature
D.	Field Winding is not excited
Answer» C. Field winding is not connected to the armature