How does the magneto ignition system work?


The figure shows a magneto ignition system for a four-cylinder engine. It consists of a magneto, instead of a battery, which produces and supplies current in the primary winding. The remaining arrangement of parts in this system is similar to that in the battery ignition system. 


The magneto consists of a fixed armature having primary and secondary windings and a rotating magnetic assembly which is driven by the engine. When the magneto rotates, current flows in the primary winding. The secondary winding passes high voltage current to the distributor, which then distributes it to the respective spark plugs.

Magneto ignition system
Magneto ignition system

In a magneto, the magnetic field is produced by means of permanent magnets whereas, in the conventional generator, the magnetic field is produced bypassing some of the generated currents through the field winding which produces the magnetic field.

Bicycle magneto Assembly
Bicycle magneto Assembly

The Magento may be either rotating armature type or rotating magnet type. In the rotating armature type magneto, the armature which carrying the primary and secondary winding and the condenser rotates between the poles of a stationary horseshoe-shaped magnet.

Watch the video below to know how the magneto ignition system works?


  1. Less space is required as compared to the Battery ignition system because the battery is not used.
  2. Simple wiring is used.
  3. Maintainance cost is low.


  1. Poor sparking at low speed.
  2. Difficult starting.
  3. There is a misfire possibility because of the variation of voltage in the circuit can occur.
  4. More expensive than the “Battery Ignition System”.

Applications or Uses:

  1. Used in motorcycles, scooters, cars, buses, and trucks, etc.
  2. Aircraft Engines.
  3. Cement Mixers.
  4. Power units, Marine engines.
  5. Natural Gas engines.
Magneto Of Scooter
Magneto Of Scooter

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Creative Blogger And Automobile Engineer.

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