The starting motor has a solenoid. When the start
pushes core (6) from the magnetic center of coil (1). Low
switch is activated electricity from the electrical system
current will energize coil (1) and make a magnetic field.
will cause the solenoid to move the starter pinion to
The magnetic field pulls core (6) to the center of coil (1)
engage with the ring gear on the flywheel of the engine.
and the contacts close.
The starter pinion will engage with the ring gear before
the electric contacts in the solenoid close the circuit
between the battery and the starting motor. When the
start switch is released the starter pinion will move away
The circuit breaker is a safety switch that opens the
from the ring gear of the flywheel.
battery circuit if the current in the electrical system goes
higher than the rating of the circuit breaker.
A heat activated metal disc with a contact point
A solenoid is a magnetic switch that uses low current
completes the electric circuit through the circuit breaker.
to close a high current circuit. The solenoid has an
If the current in the electrical system gets too high it
electromagnet with a core (6) which moves.
causes the metal disc to get hot. This heat causes a
distortion of the metal disc which opens the contacts and
breaks the circuit. A circuit breaker that is open can be
reset after it cools. Push the reset button to close the
contacts and reset the circuit breaker.
SCHEMATIC OF A SOLENOID
1. Coil. 2. Switch terminal. 3. Battery terminal. 4.
Contacts . 5. Springs. 6. Core. 7. Component
CIRCUIT BREAKER SCHEMATIC
1. Reset button. 2. Disc in operation. 3. Contacts.
4. Disc. 5. Battery circuit terminals.
There are contacts (4) on the end of core (6). The
contacts are held in the open position by spring (6) that