Winding scheme for a power tool motor

It is an object of the invention to provide an improved technique for controlling the output characteristic of a motor. Representative power tool (100) includes a tool bit (109) and a motor (121). The motor (121) drives the tool bit (109) and includes an armature (133), a commutator (137), a plurality of segments (40,41,42,43,44,45,46,47,48,49) and a plurality of armature windings (20,21,22,23,24). The armature (133) has a plurality of slots. The commutator (137) rotates together with the armature (133). Plurality of segments (40...49) is provided on the commutator (137). Respective armature windings (20...24) are connected at the both ends to the segments (40...49). Each of the armature windings (20...24) is defined by coils (A1,A2,A3,A4,A5,B1,B2,B3,B4,B5) that are wound between respective pairs of the slots of the armature (133). Each of the armature windings is formed by at least two coils (A1,A2,A3,A4,A5 and B1,B2,B3,B4,B5) connected in series. At least one of the coils (A or B) defining the armature winding (20...24) has a different number of turns (e.g. 7 or 8) of a wire wound between the associated slots from the other coils (B or A) in the same armature winding (20...24). On the same time, the total number of turns (e.g. 15) of the wire of each of the armature windings (20...24) is the same. Thus, as a result, the magnetic field around each of the armature windings (20...24) can be kept substantially the same.