Page 216 - Mechanic Diesel - TT

MECHANIC DIESEL - CITS

Starter Motor: The starter motor is a powerful electric motor, which has a small gear at one end. When the motor
is operated, the smaller gear meshes with the larger gear or the one mounted on the engine. When the starter
motor is fixed at the rear side of the engine, the pinion of the starter motor and the flywheel ring engage with the
gear and the flywheel ring rotates the gear.

Description of Starting Circuit: The diagram of the starting circuit is shown in the figure. In this, the negative
end of the battery is connected to earth and the positive end is connected to the solenoid switch installed on
the battery terminal. By connecting a wire to the input terminal of the starter switch, it is connected to the input
terminal of the solenoid winding. The other terminal of the solenoid winding is earthed. A connection from the
starter terminal of the solenoid switch is connected to the input terminal of the starter motor.
The internal connection of the starter motor is done with the field winding as well as the armature through bushes
and its other terminals are earthed. When the switch is turned on, some amount of current flows between the
battery and the starter solenoid. This current provides power to the solenoid winding, due to which the plunger,
battery and starter motor ends are connected to the solenoid switch. Conversely, when the switch is turned off,
the return spring pulls the plunger back, stopping the flow of current in the circuit. Thus the battery is separated
from the starter motor.

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CITS : Automotive - Mechanic Diesel - Lesson 62 - 66