The motor stator of the distributed winding has no convex poles, and each magnetic pole is composed of one or several coils to form a coil group according to a certain regularity. After being energized, magnetic poles of different polarities are formed, so it is also called a hidden pole type. According to the different arrangement of the embedded wiring, the distributed winding can be divided into two types: concentric and stacked.
(1) Concentric windings Concentric windings consist of several coils of similar shape but different sizes, which are embedded in a return-shaped coil group at the same center position. Concentric windings can be constructed as two- or three-plane windings depending on the wiring. The stator winding of a three-phase asynchronous motor of a general single-phase motor and a part of a low-power or large-span coil is of this type.
(2) Stacked windings are generally composed of coils of the same shape and size, with one or two coil sides embedded in each slot, and uniformly distributed one by one at the outer ends of the slots. The stacked windings are divided into a single stack and a double stack. Each slot is embedded with only one coil side, which is a single-stack winding, or a single-stack winding; each slot is embedded in two coils of different coil groups when it is placed in the upper and lower layers of the slot, which is a double-stack winding, or It is called double stack winding. Depending on the way the embedded wiring changes, the stacked windings can be derived from cross-over, concentric crossover and single-dual hybrids. Generally, the stator windings of the three-phase asynchronous motor with large power are mostly double-stacked; while the small motors use the derivative type of the single-stack winding, but the single-stack winding is rarely used.