Improvements in or relating to D.C. Electrical Machines

1,160,627. Making dynamo-electric machines. MASCHINENFABRIK OERLIKON. 9 Nov., 1967 [18 Jan., 1967], No. 50951/67. Heading B3A. [Also in Division H2] A D.C. electric machine has a stator 1 formed with main poles 4 and commutator poles 5 and is made by stamping the slots 2, 3 out of separate laminations, stamping the rotor gap, stacking the laminations, inserting an insulating sleeve 9 into each slot and sliding prewound main and commutator coils 10, 11 into the slots. The poles each have projections 6, 7 to define a narrow mouth 12 and to hold a key 13 in position. In an alternative embodiment the commutator pole 5 is slotted to receive the end of the key and the projections omitted, Fig. 3 (not shown). The punch 15 for stamping the slots comprises two main portions 15a which define the commutator poles and one edge of each adjacent main pole. Webs 15b join the main portions to define the air gap between the rotor and the stator.