ABSTRACT
Substituting eqs. (12.25) and (12.26) into the above-mentioned common factor in eq. (12.21) and simplifying yields
2N N J2 I c g
Accordingly, eq. (12.27) can be written as
(12.29)
2N /'2\ 1 (MMF)ph = s 7Tp [Kld sin(QI - wt) + 3" Kp3Kd3 sin(3Q1 - wt)
+ ~ Kp5Kd5 sin(5Q1 - wt) + 1
+ KpKd sin(QI +wt) + 3" Kp3Kd3 sin(3Q1 +wt)
(12.30)
The magnetomotive-force expression in eq. (12.30) is for one phase, and for a three-phase stator, there are three similar magnetomotive forces, produced by the three phases, which are separated in angular pOSition by 27T /3 electrical radians, or 120 electrical degrees. If the impressed stator voltage is from a balanced three-phase source, each phase voltage and each phase current will successively lag the preceding one in time by a similar angle. The resulting three-phase magnetomotive force is equal to the sum of the magnetomotive forces produced by the three individual phases, with appropriate consideration for the difference in angular position and time phase between the phases.
