Single phase armature winding can be either concentrated or distributed type.
Concentrated Armature Winding
Concentrated winding is employed where number of slots on the armature is equal to number of poles in the machine. This armature winding of alternator gives maximum output voltage but not exactly sinusoidal. The most simple single phase winding, is shown below in the figure-1. Here, number poles = number of slots = number of coil sides. Here, one coil side is inside one slot under one pole and other coil side inside other slot under next pole. Clearly the emf induced in one coil side is added to that of adjacent coil side.