TM 5-3895-379-23-1
0003
ELECTRICAL SYSTEM - Continued
7. Starter.
a. The starter is used to turn the engine flywheel fast enough to start the compression/ignition process
and make the engine run. When the engine start switch is activated, voltage from the electrical
system causes a solenoid to move a pinion toward the flywheel ring gear of the engine. The electrical
contacts in the solenoid close the circuit between the battery and the starter just before the pinion
engages the ring gear causing the starter to rotate. A starter with this type of turn-on is known as a
positive shift starting motor.
b. When the engine begins to run, the overrunning clutch portion of the pinion drive prevents damage
to the starter caused by excessive speeds by breaking the mechanical connection. The pinion will
stay meshed with the ring gear until the engine start is released from the start position. A returned
spring in the overrunning clutch returns the clutch to its rest position.
8. Fuses. Fuses are safety devices which open an electrical circuit in the event of a short or malfunction to
protect the system from damage. A filament inside the fuse allows a measured amount of current to travel
through the circuit. The filament disintegrates when too much current attempts to pass through the fuse.
Once a fuse has "blown" it must be replaced. Fuses are provided for each of the major system circuits.
9. Engine Start Switch. The engine start switch is a rotary key-type switch that turns the electrical system on
or off and activates the starter. When the start switch is turned to the START position (held to far right),
electricity is sent through the neutral start and main relays. After these relays, the electricity then goes to
the starter.
10. Starter Relay. The starter relay allows electricity to flow to the starter when the engine start switch is in the
START position.
11. Neutral Start Relay. The neutral start relay is a safety device that stops the flow of electricity to the starter
when the propel control lever is set in a position other than neutral.
12. Lights Circuit Breaker. The lights circuit breaker is a heat-triggered switch that opens the lights circuit when
the current in the electrical system goes higher than the rating of the circuit breaker (20 amps). Push the
reset button to close the circuit again.
13. Main Relay. The main relay allows electricity to flow to all circuits only when the engine start switch is in the
ACCESSORY, RUN, or START positions.
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03/15/2011Rel(1.8)root(thrywp)wpno(G00006)
