An electrical machine includes a casing including a base wall provided with a projection projecting from the base wall towards the inside of the casing. A stator includes a core having a plurality of pole shoes, a plurality of conductors wound on the pole shoes to form a plurality of coils constituting a stator winding. Insulators are interposed between the core and the stator winding. A coil of the winding has an end portion engaged with the projection for heat exchange. The insulators include a housing for a first number of turns of the coil and a second housing for a second number of turns of the coil. The first and second housings are shaped such that a layer of the turns of the end portion abutted against the projection is defined by stretches of the conductors all substantially coplanar with each other.