Explore topic-wise MCQs in Electrical Machines.

This section includes 4 Mcqs, each offering curated multiple-choice questions to sharpen your Electrical Machines knowledge and support exam preparation. Choose a topic below to get started.

1.

If m is the maximum value of flux due to any one phase, then resultant flux in 2 phase and 3 phase AC machines would respectively be given by _________

A. <sub>m</sub> and 1.5 <sub>m</sub>, both rotating
B. <sub>m</sub> and 1.5 <sub>m</sub>, both stand still
C. <sub>m</sub> stand still and 1.5 <sub>m</sub> rotating
D. 1.5 <sub>m</sub> and 2 <sub>m</sub>, both rotating
Answer» B. <sub>m</sub> and 1.5 <sub>m</sub>, both stand still
Discussion
2.

In case of the 3 phase winding with delta or star connection without neutral, if one of the supply lines gets disconnected, then the MMF becomes __________

A. Stationary and pulsating
B. Rotating with synchronous speed
C. Rotating with sub synchronous speed
D. Rotating with super synchronous speed
Answer» B. Rotating with synchronous speed
Discussion
3.

What does the space angle in the equation Fr( ,t)=3/2Fmcos( - t) for MMF produced when 3-phase balanced windings excited by three phase balanced currents represent?

A. MMF wave at any moment is sinusoidally distributed in space
B. Entire MMF waveform is travelling at (constant angular speed) synchronous speed
C. MMF wave is of constant amplitude
D. None of the mentioned
Answer» B. Entire MMF waveform is travelling at (constant angular speed) synchronous speed
Discussion
4.

If F1 is the constant amplitude of fundamental rotating MMF wave, the for the space harmonics of order 6K-1 (where K=1,2,3 .), the harmonic MMF wave is of _____________

A. Constant amplitude and stationary in space
B. Constant amplitude and rotates along F<sub>1</sub>
C. Varying amplitude and rotates along F<sub>1</sub>
D. Constant amplitude and rotates against F<sub>1</sub>
Answer» C. Varying amplitude and rotates along F<sub>1</sub>
Discussion