Two stage thrust drive for starter motors - has pinion engagement winding excited only until main contacts close

摘要

The two stage thrust has an engagement relay with an engagement magnet. Current passes through the holder winding during the whole of the starting process. The engagement winding is only excited until the starter motor main contacts are closed. The keeper winding (18) is connected to the vehicle storage battery via a starter switch (2) and earth (17). The engagement winding (22) is part of a second circuit (20) whose one end is connected to the main contact bridge (19) from the storage battery. The second end is connected between the main current contact and the starter motor field winding (6).