Page 219 - Mechanic Diesel - TT

MECHANIC DIESEL - CITS

1 Starter motor system
2 Solenoid Switch System
3 Self-starter system
Starter Motor System: To start the engine, the minimum rotational speed of the engine’s crankshaft should be
100 rpm. This action is called engine cranking. Because it is very difficult to turn the engine at that speed by hand
or with a lever, a starter motor is used to start the engine. The starter motor is fixed to the rear side of the engine.
When the starter switch is turned on, the pinion of the starter motor engages with the flywheel ring gear to rotate
the flywheel.
Working Principle of Starter Motor
When current flows through an armature coil placed between two stationary magnets, an emf is induced in the
coil. Is induced and the armature coil starts rotating.
Self-Starter System
Self-starter is also based on the same principle Lills 146 Azole Baje & health folk

Then a mechanical force is generated on that conductor, which rotates it. The direction of this force is determined
by Fleming’s right hand rule. plain to kho bluble pie the poliok link 1946 17sne Huey be yoj L t will start working.
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According to this rule, one has to open one’s right hand in such a way that the fore-finger, middle finger Taltk lalse
196

Starting system
Now place your hand along the conductor in which the direction of current is to be found as per the position shown
in the figure. Thus, the direction of the magnetic field is indicated by the index finger, the direction of motion of the
conductor is indicated by the thumb and the EMF induced in the conductor is indicated by the middle finger. And
the direction of current flow can be known.

Fleming’s right hand rule

Working principle of self starter
In the given figure, current is flowing in a conductor. In this, the direction of current flow is shown by wires. Due
to the current flowing in the conductor, a magnetic field is generated around it, whose direction is anti-clockwise.
This conductor is installed in the magnetic field. The lines of force in this region are straight from the North Pole
to the South Pole.
As shown in the Fig. The circular magnetic field on the left side of the conductor is in the same direction as the
perpendicular field of the magnet, but the field on the right side of the conductor is in the opposite direction. Thus,
the field on the left side of the conductor is strong and the field on the right side is weak, due to which the field on
the left side of the conductor gets distorted, because the properties of the magnetic lines of force in this region
become like rubber. Due to this distortion in the magnetic field, the more current flows in the conductor, the more
the magnetic force lines will be distorted and the more force will rotate the conductor at a faster speed.

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CITS : Automotive - Mechanic Diesel - Lesson 62 - 66