SKEDSOFT

Automobile Engineering

Introduction:
           
A dynamo is a machine used to convert mechanical used to convert mechanical energy into electrical energy. When it is driven by the engine it produces electricity for running all the electrical circuits of the automobile and keeps the battery in charged condition. This is the function of dynamo.

Principle of Dynamo:

 

“When a conductor moves in a magnetic field, current is produced in it. The direction of current is determined by Flemming’s right hand rule”.

Flemming’s Right Hand Rule

If thumb, fore finger and middle finger of right hand are stretched so that they are mutually perpendicular then the direction of induced current in the conductor can be found out by this rule.

 

                “If the fore finger indicates the direction of magnetic field and the thumb shows the direction of motion of the conductor, then middle finger will indicate the direction induced current”. This is called Flemming‟s right hand rule.

 

  • A magnetic field acts between north and south poles of magnets. There are lines of forces between two poles.
  • When the conductor moves such that lines of force are cut, current is induced in the conductor. This current can be used to run any electrical components, e.g. lights and charging system, etc.
  • The current induced in the conductor depends upon the rate at which force lines are cut and strength of magnetic field, etc.
  • When the conductor (armature of dynamo) is rotated (by engine) in the magnetic field, a current is induced in the conductor.
  • The direction of flow of current in the two legs of conductor is opposite because their direction of motion is also opposite.
  •  The two ends of conductor connected to the commutator