Abstract: A method of manufacturing frontal commutators including placing mica sheets in precut grooves of a commutator blank and contacting the blank to retain the mica sheets in place.

Abstract: A rotor having a thermal bridge embedded in the rotor for transferring heat released by the commutator of the rotor to the inner bushing of the drive shaft of the electric motor thereby cooling the rotor. The bridge may either be formed of a solid metal piece or a fluid containing conduits; both of which are electrically insulated from the commutator. Orifices are formed in the thermal bridge so that both halfs of the resin molded commutator can be joined together and form a stronger rotor.

Abstract: An electric motor rotor assembly and method of forming the flat rotor wherein an inner tubular casing and a commutator are molded in a first mold thereby forming between the casing and the commutator a molded resin intermediate section. After the so molded commutator is removed from the first mold, the windings for the rotor are first cold crimped and then hot crimped to the commutator thereby breaking the insulation and providing a good electrical connection. After the windings are attached to the commutator, it can then be tested to check the windings for electrical continuity. After the testing, the assembly is placed into a second mold where resin is injected about the windings forming a resin enclosing sheath.

Abstract: Continuous rotation is imparted to a coil holder about its rotational axis carried by a cam assembly to which rotation is intermittently imparted about a second offset rotational axis through a clutch-brake mechanism. The cam assembly controls operation of a wire-guide mechanism through which wire is fed to the coil holder to form a dynamo-electric machine winding having a particular geometrical configuration.