If peak value of phase mmf is ___

Electrical Engineering MCQ Electrical Machines MCQ
1

If peak value of phase mmf is Fmax , then peak value of the rotating field caused by three phase is

A. (3/2)Fmax.
B. Fmax.
C. 3Fmax.
D. (1/2)Fmax.

Show Answer

Answer: A

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2

The answer is A. (3/2)Fmax.

The peak value of the rotating field caused by three phase is equal to the square root of 3 times the peak value of the phase mmf. This is because the three phase mmfs are displaced by 120 degrees from each other, and when they are added together, they create a rotating magnetic field.

The formula for the peak value of the rotating field is:

F_rot = sqrt(3) * F_phase

where:

  • F_rot is the peak value of the rotating field
  • F_phase is the peak value of the phase mmf

Therefore, if the peak value of the phase mmf is Fmax, then the peak value of the rotating field is:

F_rot = sqrt(3) * Fmax = (3/2)Fmax