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

Theory of Operation2.5.8.1. Normal/Reverse ContactsThe first unlocking movement of the cam bar opens either the normal or reversecontacts, depending on the direction of operation, as shown in Figure 2–29.1/32" TO 1/16"Figure 2-29. Normal/Reverse Contacts In Open Position2.5.8.2. Motor Control ContactsDuring motor operation, both motor control contacts are closed due to detector yokepivoting to center position. Only one of two motor control contacts provides energy tothe electrical circuit for the motor winding. At completion of movement, the detectoryoke pivots, as shown in Figure 2–30, opening only that motor control contact providingenergy to the electrical circuit, thereby de-energizing motor. The other motor controlcontact, still closed, is part of motor snub circuit and is in position to apply energy toswitch the motor for next switch movement.“Figure 2-30. Motor Control Contacts In Open PositionP1293, Rev. Jun/07 2–28 Alstom Signaling Inc.