6. ELECTRICAL
Starter Magnetic Switch
The starting motor requires a large current of
approximately 100 A to operate. To minimize
resistance, a large cable is used for wiring,
also, a switch with heavy duty contacts is
required. Sparking across the contacts will
result, as well as resistance depending upon
the contact pressure, when the contacts are
opened suddenly to shut off the flow of large
current. To cope with these conditions, a
magnetic switch is used separately which is
operated electrically by a small current
through a push button starter switch.
Inspection
1. Primary coil continuity test.
If there is no continuity, the primary coil
is open.
If a clicking noise is heard when a 12 V
battery is connected to the two leads of
the coil, the primary coil is satisfactory.
2. After long use, the magnetic switch con-
tacts will become pitted or burnt from
the large current which flows across it,
and gradually build up resistance which
may prevent the current from flowing.
Connect 12 V to the primary coil leads
of the magnetic switch.
If there is no
continuity across the switch contacts,
the switch is defective.
Fig. 303
(D Stopper
® Stopper holder
@ Washer
© Roller A
® Contact spring
® Flat washer
® Plunger holder
® Plunger shaft
® Plunger
@) Contact bolt
@ Case
@ Contact plate
@ Yoke
® Coil bobbin
@ Coil complete
@ Return spring
@ Body
Fig. 304 Primary coil continuity test
101
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