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MAGNETO IGNITION SYSTEM , ITs ADVANTAGES AND DISADVANTAGES

 In this system, The battery is replaced with a magneto. This system is used in Two wheelers like motor cycles, scooters etc.

Construction :

 It consists of a switch , magneto , contact breaker, condenser, distributor and spark plugs.



WORKING :

The Magneto Ignition system consists of a rotating magnetic assembly driven by a engine and a fixed armature. The armature consists of primary and secondary windings. The primary circuit consists of a primary winding condenser and contact breaker. The secondary circuit consists of a secondary windings, distributor and spark plugs.

When the contact breaker points are closed :
 
1. The current flows in the primary circuit.

2. This produces a magnetic field in the primary winding.

3. When the primary current is at the highest peak, the contact breaker points will be opened by the cam,

When the contact breaker points are opened :
 
1. There is a break in the primary circuit.

2. The magnetic field in the primary winding is suddenly collapsed.

3. A high voltage (15000 volts) is generated in the secondary winding.

4. This  high voltage is distributed to the respective spark plugs through the rotor of the distributor .

5. The high voltage tries to cross the spark plug gap and a spark is produced in the gap. This spark ignites the fuel-air mixture in the engine cylinder. 

ADVANTAGES :

* It has no maintenance problem like coil ignition (i.e for battery)
* When the speed increases, it provides better intensity of spark and thus provides better combustion as compared to battery coil ignition system.
* Less space is required as compared to Battery Ignition System. 
* It is very light in weight and compact in size.

DISADVANTAGES :

* Initial cost is very high as compared to Coil Ignition System.
* Minimum 75 rpm is necessary to start the engine.
* For higher power engines, some other devices are necessary to start Ignition.






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