Models 5E, 5F, 5G & 5H Electric Switch Machines: Single ... - Alstom

Theory of Operation2.5.1.1. Commutator and BrushesThe commutator is part of the armature to which the windings are connected. Thecommutator consists of an insulated steel hub with wedge shaped insulated coppersegments arranged around the hub.Brushes made from current conducting material ride on the commutator, making anelectrical connection between the commutator and the power supply. Brushes ride onthe outer edges of commutator bars that are connected to armature windings, and areseated to match the shape of the commutator. To insure proper electrical contact, brushpressure to the commutator is set to 1-1/4 to 1-3/4 pounds.The commutator and brushes work together to provide current to the correct armaturewinding(s) to generate torque as shown in Figure 2–10.Figure 2-10. Commutator and BrushesA heater is located over the commutator and brushes to eliminate moisture in the motorarea. The heater is energized by a 110 VAC source.P1293, Rev. Jun/07 2–11 Alstom Signaling Inc.