Explore topic-wise MCQs in Dc Machines.

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.

From magnetization characteristic at If = 7.1 A, Ea = 225 V at 1000 rpm. What will be the terminal voltage at speed 950 rpm?

A. 225 V
B. 235 V
C. 214 V
D. 220 V
Answer» D. 220 V
2.

For a given compound DC machine, Net field current obtained from characteristic is equal to 7.5 A, where shunt field current is equal to 5 A, armature current is 505 A, demagnetizing current equal to 0.95 A and shunt field winding of 1000 turns at rated speed of 1000 rpm. What will be the series field turns?

A. 7
B. 8
C. 5
D. 9
Answer» B. 8
3.

From magnetization characteristic at If = 7.1 A, Ea = 225 V at 1000 rpm. What will be the terminal voltage at speed 950 rpm?

A. 225 V
B. 235 V
C. 214 V
D. 220 V
Answer» D. 220 V
4.

External characteristics of DC shunt motor lies in ______________

A. 1<sup>st</sup> quadrant
B. 2<sup>nd</sup> quadrant
C. 1<sup>st</sup> and 2<sup>nd</sup> quadrant
D. 4<sup>th</sup> quadrant
Answer» D. 4<sup>th</sup> quadrant
5.

How demagnetization effect of armature reaction is shown graphically?

A. By shifting origin towards +ve y axis
B. By shifting origin towards +ve x axis
C. By shifting origin towards -ve y axis
D. By shifting origin towards -ve x axis
Answer» E.
6.

For determining IaRa maximum _____________

A. Distance between R<sub>f</sub> line and v+ I<sub>a</sub>R<sub>a</sub> line is taken
B. Distance between OCC and v+ I<sub>a</sub>R<sub>a</sub> line is taken
C. Maximum Distance between OCC and v+ I<sub>a</sub>R<sub>a</sub> line is taken
D. Can’t calculated graphically
Answer» D. Can‚Äö√Ñ√∂‚àö√ë‚àö¬•t calculated graphically
7.

How armature resistance effect is shown graphically?

A. By adding I<sub>a</sub>R<sub>a</sub> product horizontally with R<sub>f</sub> line
B. By subtracting I<sub>a</sub>R<sub>a</sub> product vertically with R<sub>f</sub> line
C. By adding I<sub>a</sub>R<sub>a</sub> product vertically with R<sub>f</sub> line
D. By subtracting I<sub>a</sub>R<sub>a</sub> product horizontally with R<sub>f</sub> line
Answer» D. By subtracting I<sub>a</sub>R<sub>a</sub> product horizontally with R<sub>f</sub> line
8.

Rf line intersects with OCC in ________

A. 1<sup>st</sup> quadrant
B. 2<sup>nd</sup> quadrant
C. 3<sup>rd</sup> quadrant
D. 4<sup>th</sup> quadrant
Answer» B. 2<sup>nd</sup> quadrant
9.

No load point of DC generator is __________

A. Intersection of OCC and Rf line
B. Point on the Y axis at rated field current
C. Point on the X axis at rated terminal voltage
D. Can’t find through graphical interpretation
Answer» B. Point on the Y axis at rated field current