Hello, I'm a little confused about synchronous machines. Specifically, I don't understand how the armature coils are wound. In discussing how the windings are configured in a three-phase synchronous machine, my textbook provides several diagrams which suggest that the windings of a coil go between opposite slots.(adsbygoogle = window.adsbygoogle || []).push({});

Are all synchronous machines constructed in this way or is it possible to have other configurations of armature windings? For example, could the coils be wound between adjacent slots?

Also, I don't understand the derivation my textbook gives for EMF induced in the coil. It obtains the air gap flux linked per coil by integrating air gap flux density around the interior of the stator from x=0 (x is an arc length co-ordinate fixed with respect to the stator) to x=2*Pi*R/p (R is the stator interior radius, p is the number of rotor poles) and multiplying the result by the axial length of the rotor. The induced EMF is then obtained by application of Faraday's law.

My problem with this derivation is that I don't understand how the air gap flux is linked to the coil. It's possible I have misunderstood the meaning of "flux linkage". I understand it to be equal to:

[tex]N\Phi = N\int_A{{\bf B}\cdot{\bf dS}[/tex]

whereNis the number of turns in the coil, [tex]\Phi[/tex] is the flux linked to one turn of the coil, [tex]{\bf dS}[/tex] is a unit vector normal to the plane of the coil andAis the planar surface bounded by the coil. This would mean that air gap flux is only linked (and therefore EMF-inducing) when it flowsthroughthe loop of a coil, not when it simply intercepts the edges of a coil as seems to be the case with coils wound between opposite slots. Could somebody please explain this to me?

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# Synchronous machine confusion

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