What is Magneto Ignition System?- Parts & Working

Magneto Ignition System Diagram

What is Magneto System?

A magneto is an electrical generator that uses permanent magnets to produce periodic pulses of alternating current. Magnetos were also adapted to produce pulses of high voltage in the ignition systems of some gasoline-powered internal combustion engines to provide power to the spark plugs.

What is Magneto Ignition System?

An ignition magneto, or high tension magneto, is a magneto that provides current for the ignition system of a spark-ignition engine, such as a petrol engine. It produces pulses of high voltage for the spark plugs. The older term tension means voltage.

The use of magneto ignition today is mainly limited to engines for which no other power supply is available, such as lawnmowers and chainsaws. It is also widely used in aviation piston engines, although an electrical supply is usually available.

In this case, it is assumed that the self-sufficient operation of the magnet offers increased reliability. In theory, the magnet should keep running as long as the engine is turning.

Parts of Magneto Ignition System

These are the main parts of Magneto Ignition Systems:

  • Transformer core
  • Contact Breaker
  • Cam
  • Capacitor
  • Ignition Switch
  • Distributor
  • Spark Plug

1. Transformer core

The main part of the magneto-ignition system is the transformer core, which consists of two types of windings.

One is the primary winding and the other is the secondary winding. The primary winding is also referred to as the low-voltage winding and the secondary winding as the high-voltage winding.

One end of the primary winding is grounded and the other end is connected to the connection, the contact breaker, and the capacitor.

2. Contact Breaker

The contact breaker is regulated by the cam and when the breaker is open, current flows through the capacitor and charges it. It is generally used for making and breaking the Primary circuit. The pivoted arm(link) has a heel attached in the middle which breaks the contact point due to the action of a cam.

3. Cam

One end of the shaft is connected with the cam and the other end is connected with the magnet which has two poles, North and South.

4. Capacitor

The main job of the capacitor is to store the charger. The capacitor used here is a simple electrical capacitor. One end is connected with the primary winding and the other end is grounded and it is generally used to store the charge coming from the primary winding.

5. Ignition switch

Works for off and on the vehicles and this is set to the parallel of the capacitor because it helps to avoid the damage of excessive air.

6. Distributor

A distributor is provided for distributing the ignition surges to individual spark plugs in the correct sequence with respect to the firing order. It consists of the rotor in the middle and the metallic electrode on the periphery.

These metallic electrodes are directly connected to the spark plugs and are also known as the Ignition harness. As the rotor rotates, it passes the high tension current to the ignition harness which then carried these high tension currents to the spark plugs.

7. Spark Plug

Spark Plug is the last component of the Magneto Ignition System. It consists of 2 electrodes, one attached to the high tension current-carrying wires, and the other is grounded.

The potential difference between these electrodes ionizes the gap present between them and thus a Spark is generated which ignites the combustible mixture.

Magneto Ignition System Diagram

Magneto Ignition System Diagram
Magneto Ignition System Diagram

How does a magneto ignition system work?

The magneto is a self-contained generator of high voltage that provides ignition to an engine through spark plugs. The moment the contact points open, a rapid magnetic flow generates a high voltage in the secondary coil, which ignites the spark plug, thus firing the engine

Magneto is used in the magneto ignition systems. When the engine starts, it helps the magnet rotate, thus generating energy in the form of high voltage. Then one end of the magnet is grounded via a contact switch and the ignition capacitor is connected to its parallel.

The contact breaker is controlled by the cam. When the switch is open, current flows through the capacitor and charges it.

Now the capacitor acts as a charger, the primary current flow is reduced, which reduces the overall magnetic field generated in the system.

This increases the voltage in the capacitor. This increased high voltage in the capacitor acts as an EMF and thus creates the spark on the right spark plug through the distributor.

And in the starting phase, the speed of the engine is low and therefore the voltage generated by the magneto is low.

However, as the engine speed increases, so does the voltage generated by the magneto, which also increases the flow of current.

Applications of Magneto Ignition System

The magneto Ignition Systems used in:

  • This system is used to produced electricity (a battery system uses its battery) and to run the vehicles.
  • This is mainly used in two-wheeled vehicles today.
  • A rotating magnet generates high voltage.
  • This is also used in various places such as buses, power units, marine engines, tractors, outboard engines, washing machines, and natural gas engines.

Advantages of Magneto Ignition System

These are the advantages of Magneto Ignition Systems:

  • This magneto ignition system requires less maintenance compared to the battery ignition system.
  • This is more useful because it does not use a battery.
  • It takes up less space.
  • The magnet creates a circuit
  • No battery is required, so there is no problem with battery discharge
  • The efficiency is improved by high-intensity sparks.

Disadvantages of Magneto Ignition System

Although there are some disadvantages:

  • It has a starting problem due to the low RPM when starting the engine.
  • It’s more expensive than a battery ignition system.
  • There is a possibility of a misfire due to leakage as voltage fluctuations in the wiring can occur.

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