Explore topic-wise MCQs in Dc Machines.

This section includes 19 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.

For a DC motor taking 10kW power from 230V mains, having armature resistance and field resistance equal to 0.08Ω and 115Ω resp. The value of armature current is_____

A. 45.68 A
B. 43.48 a
C. 41.48 A
D. Data insufficient
Answer» D. Data insufficient
Discussion
2.

What is the armature current for a DC generator if terminal voltage is observed to be 245V and open circuit voltage is equal to 250V, where armature resistance is 0.05Ω?

A. 10A
B. 100A
C. 1KA
D. 1A
Answer» C. 1KA
Discussion
3.

For a DC generator feeding 100kW power into 230V mains, having armature resistance and field resistance equal to 0.08Ω and 115Ω resp. The value of armature current is_____

A. 436.8 A
B. 434.8 a
C. 432.8 A
D. Data insufficient
Answer» B. 434.8 a
Discussion
4.

What is the armature current for a DC motor if terminal voltage is 255V and open circuit voltage is equal to 250V, where armature resistance is 0.05Ω?

A. 10A
B. 100A
C. 1KA
D. 1A
Answer» C. 1KA
Discussion
5.

When torque of the electromagnetic origin is in the direction of rotation of armature, machine is said to be operating in which of the following mode?

A. Depends on other parameters
B. Generating
C. Motoring
D. Inducing
Answer» D. Inducing
Discussion
6.

When Ea

A. Depends on the Shaft speed
B. Generating
C. Motoring
D. Inducing
Answer» D. Inducing
Discussion
7.

A 4-pole Dc wound machine is lap wound with 400 conductors. The pole shore is 20 cm long and average flux density over one-pole pitch is 0.4 T, the armature diameter being 30 cm. Here, motor is drawing 25 A current at 1500 rpm.What is the available torque (N-m) at shaft?a) 29.9b) 59.8c) 14.95d) 44.85 4.When Ea>Vt machine is said to be operating in which of the following mode?

A. 29.9b) 59.8c) 14.95d) 44.85 4.When Ea>Vt machine is said to be operating in which of the following mode?a) Depends on the Shaft speed
B. 59.8c) 14.95d) 44.85 4.When Ea>Vt machine is said to be operating in which of the following mode?a) Depends on the Shaft speedb) Generating
C. 14.95d) 44.85 4.When Ea>Vt machine is said to be operating in which of the following mode?a) Depends on the Shaft speedb) Generatingc) Motoring
D. 44.85 4.When Ea>Vt machine is said to be operating in which of the following mode?a) Depends on the Shaft speedb) Generatingc) Motoringd) InducingView Answer
Answer» B. 59.8c) 14.95d) 44.85 4.When Ea>Vt machine is said to be operating in which of the following mode?a) Depends on the Shaft speedb) Generating
Discussion
8.

Product of torque and mechanical angular velocity ω is_____

A. Ea/ω
B. Ea*Ia
C. ω/Ea
D. Can’t tell
Answer» C. ω/Ea
Discussion
9.

WHAT_IS_THE_ARMATURE_CURRENT_FOR_A_DC_MOTOR_IF_TERMINAL_VOLTAGE_IS_255V_AND_OPEN_CIRCUIT_VOLTAGE_IS_EQUAL_TO_250V,_WHERE_ARMATURE_RESISTANCE_IS_0.05‚ÄÖ√Ñ√∂‚ÀÖ√´¬¨‚ÀÇ??$#

A. 10A
B. 100A
C. 1KA
D. 1A
Answer» C. 1KA
Discussion
10.

What is the armature current for a DC generator if terminal voltage is observed to be 245V and open circuit voltage is equal to 250V, where armature resistance is 0.05Ω?$#

A. 10A
B. 100A
C. 1KA
D. 1A
Answer» C. 1KA
Discussion
11.

For a DC generator feeding 100kW power into 230V mains, having armature resistance and field resistance equal to 0.08Ω and 115Ω resp. The value of armature current is_____$#

A. 436.8 A
B. 434.8 a
C. 432.8 A
D. Data insufficient
Answer» B. 434.8 a
Discussion
12.

For a DC motor taking 10kW power from 230V mains, having armature resistance and field resistance equal to 0.08Ω and 115Ω resp. The value of armature current is_____$

A. 45.68 A
B. 43.48 a
C. 41.48 A
D. Data insufficient
Answer» D. Data insufficient
Discussion
13.

Simple equation of DC machine operating in motoring mode, with non-zero Ra value is________

A. Vt = Ea – Ia/Ra
B. Vt = Ea + Ia*Ra
C. Vt = – Ea + Ia*Ra
D. Vt = Ea – Ia*Ra
Answer» C. Vt = ‚Äö√Ñ√∂‚àö√ë‚àö¬® Ea + Ia*Ra
Discussion
14.

When torque of the electromagnetic origin is in the opposite direction of rotation of armature, machine is said to be operating in which of the following mode?

A. Depends on other parameters
B. Generating
C. Motoring
D. Inducing
Answer» C. Motoring
Discussion
15.

Simple equation of DC machine operating in generating mode, with non-zero Ra value is________

A. Vt = Ea – Ia/Ra
B. Vt = Ea + Ia*Ra
C. Vt = – Ea + Ia*Ra
D. Vt = Ea – Ia*Ra
Answer» E.
Discussion
16.

When Ea>Vt machine is said to be operating in which of the following mode?

A. Depends on the Shaft speed
B. Generating
C. Motoring
D. Inducing
Answer» C. Motoring
Discussion
17.

A 4-pole Dc wound machine is lap wound with 400 conductors. The pole shore is 20 cm long and average flux density over one-pole pitch is 0.4 T, the armature diameter being 30 cm. Here, motor is drawing 25 A current at 1500 rpm.

A. at shaft?
B. 29.9
C. 59.8
D. 14.95
Answer» B. 29.9
Discussion
18.

Condition for linear magnetization is______

A. φ α I<sub>f</sub>
B. φ α Ia
C. φ α 1/I<sub>f</sub>
D. φ α 1/Ia
Answer» B. ‚âà√¨‚àö√∫ ‚âà√≠¬¨¬± Ia
Discussion
19.

Product of torque and mechanical angular velocity ω is_____

A. Ea/ω
B. Ea*Ia
C. ω/Ea
D. Can’t tell
Answer» C. ‚âà√¨‚àö¬¢/Ea
Discussion