Explanation: It is the decomposition of the MMF of a single phase winding into two counter rotating MMF waves, but are not actually produced and only one stationary MMF wave pulsating along its magnetic axis is produced. 4. What does the space angle α in the equation Fr(α,t)=3/2Fmcos(α-ωt) 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:A
Explanation: It is the decomposition of the MMF of a single phase winding into two counter rotating MMF waves, but are not actually produced and only one stationary MMF wave pulsating along its magnetic axis is produced. 4. What does the space angle α in the equation Fr(α,t)=3/2Fmcos(α-ωt) 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
Explanation: The space angle α means that MMF wave at any moment is sinusoidally distributed in space along the air-gap periphery. 5. Three phase voltages are applied to the three windings of an electrical machine. If any two supply terminals are interchanged, then the rotating MMF wave _____________