After completing the harmonic analysis of rotating magnetomotive force curves it was determined that the conditional amplitude of the fundamental harmonic of rotating magnetomotive force for the analysed motor was [F.sub.m11] = 0,914 [9], and the same amplitude generated by six-phase winding was [F.sub.m12] = 1,829.
Despite that windings of the investigated motors are identical only in part (windings of the same type, 2[p.sub.1] = 2[p.sub.2], [Z.sub.1] = [Z.sub.2]), the instantaneous spatial distributions of rotating magnetomotive forces generated by them are identical at any moment of time, as it can be seen from Fig.
Analysis of the considered short pitch coil winding indicates, that during one pole pitch the relative magnetomotive force [F.sub.1]([phi]) has the shape, shown in Fig.
Space harmonic spectrum of each winding magnetomotive force can be obtained on the base of Fourier series [12].
where [F.sub.v'(")m]--amplitude of v-th harmonic of rotating
magnetomotive force; [F.sub.i]--conditional height of the i-th rectangle of the stair-shaped
magnetomotive force halfperiod; [[beta].sub.i]--width of the i-th rectangle of the stair-shaped
magnetomotive force half-period, expressed in electrical degrees; [[gamma].sub.i]--asymmetry of the i-th rectangle of the stair-shaped
magnetomotive force half-period in respect of central axis of this half-period, expressed in electrical degrees; k-number of rectangles which constitute the stair-shaped
magnetomotive force half-period; v--series number of odd space harmonic; v"--series number of even space harmonic.
here [F.sub.i] - the apparent size of the i-th rectangle of
magnetomotive force; [[beta].sub.i] - the width of the i-th rectangle, expressed in electrical degrees of fundamental space harmonic; k - number of rectangles, which form the stairshape curve of half-period of
magnetomotive force; v number of odd space harmonic.
1, a, the conditional changes of
magnetomotive force in the slots of magnetic circuit are determined (Table 3).
Its magnetic circuit is composed of the
magnetomotive force [F.sub.m], electromagnet magnetic core with the magnetic resistance [R.sub.mm] and gap with the magnetic resistance [R.sub.m0].
2, b, the amplitude value of rotating
magnetomotive force of the v-th harmonic [F.sub.mv] is calculated using this analytical expression [4]:
Spatial distribution of rotating
magnetomotive force in the defined moment of time was formed according to results presented in Table 2 (Fig.
Functions of instantaneous periodic rotating
magnetomotive force of concentrated three-phase winding are square-shaped.
The reluctance force is produced by interaction of stator
magnetomotive forces (mmf) and a reluctance variation produced by a toothed reactive part.
