115. Magnetic Switch
a. Description (fig. 32). The magnetic switch closes the starting circuit through. the magnetic pull of a solenoid
plunger (11) which carries a contact disk (14). The contact disk strikes two contacts that are connected with the external
switch terminals (5). The contact disk is mounted on springs (10) and (15) to make the opening and closing action more
positive and to assure contact over the full surface. When the contacts are closed, the current flows to the starting motor,
where it is converted into mechanical energy for the cranking of the engine. This type of magnetic switch is used with
starting motors having bendix drive and cannot be used on starting motors with an overrunning clutch.
Coil winding terminal stud
Coil winding terminal nut
Switch terminal lockwasher
Switch terminal screw
Molded terminal ring
Contact disk spring
Figure 32. Magnetic switch, end and sectional
(1) Remove the magnetic switch stud nut (2) and lockwasher (7). Disconnect the battery cable (14) from the
magnetic switch (4). Tape the battery cable to prevent accidental arcing.
(2) Remove the magnetic switch stud nut (2) and washer (3) and disconnect the starting motor cable (20) from the
magnetic switch (4).
(3) Unscrew the magnetic switch terminal nut (5) and disconnect the lead (6).