An improved stator (28) for rotating electrical machines with single-layer stator windings consisting of a plurality of pre-formed coils (22) of equal angular pitch. The stator (28) has a first cylindrical surface in which a plurality of circumferentially spaced winding slots (30) are formed and in which the axially-extending winding runs (24) of the pre-formed coils (22) are positioned. The two winding runs (24) of each coil (22) will each be positioned in a winding slot (30) and the two winding slots (30) that receive the coil (22) define a winding slot pair. The improvement arises from the fact that the winding slots (30) of each winding slot pair extend into the stator (28) in substantially parallel directions. This means that the axially-extending winding runs (24) of each pre-formed coil (22) may also be substantially parallel and need not be angled towards each other. This enables the stator (28) to be easily wound as each pre-formed coil (22) may be simply and easily slotted into a parallel winding slot pair.