Commutator bar construction for small machines - is fabricated from copper and steel parts welded together and held in insulation moulding

摘要

The bar matches the material to the duty, and also gives a saving in copper usage. The copper for the contact part of the segment is formed as a strip (9) bonded to a steel backing (10). Welded to the steel strip are anchoring lugs (6,7), typically formed from discrete pieces and also of steel. These lugs may be extended at one end to give the electrical contact point (8) for the machine winding ends. The strip assembly is then formed into a cylinder with the anchor lugs on the inside, and the internal space filled with an insulating resin with good mechanical properties. After curing, the exposed strip is slit axially to give the commutator bars. The number of anchoring lugs on any one bar can be selected to suit the mechanical operating conditions. The form of construction allows the material to be matched to the mechanical loading.