How Does a Magneto Work?

Magneto is a compact and fairly reliable generator used in small gasoline engines that do not require batteries, such as those in lawn equipment, dirt bikes, motorcycles, jet skis, dynamics, etc. outboard engines and RC model airplanes. Because they produce a strong but short electrical pulse rather than direct current, magnets are ideal for sending sparks into the spark plug, which is the part that drives the internal combustion process and powers the engine. . Because of their reliability and size, magnets were used in aircraft and they were the power behind the ringing of early telephones. The principle of magnets is exactly the opposite of electromagnets.

While an electromagnet uses a current flowing through a coil to create a magnet, an electromagnet uses a magnetic field near the coil, called the armature, to generate an electric current. Therefore, a magnet consists of three essential parts. The armature, usually U-shaped, has a primary coil of thick wire and a secondary coil of thin wire wound around it in several layers.

A flywheel with two strong magnets is used to create a magnetic field around the armature. Finally, an electrical control element, at least usually a circuit breaker and a capacitor, disrupts the electromagnetic field and directs the current generated from the magnet where it is needed. To generate electricity, the flywheel had to rotate or the coil had to move between the poles of the magnet, which is why early phones had a crank. With each revolution, an electromagnetic field is generated in the armature winding.

A cam on the electrical device contacts the armature, disturbing the magnetic field and generating a voltage in the primary coil. The high voltage of the secondary coil relative to the primary will amplify the voltage of the current as it is directed to the spark plug. The cam will then disconnect the armature and the electromagnetic field will regenerate for a new electrical pulse. The whole process takes a few seconds. 

For normal engine operation, a magnet must be installed so that its activation time matches the compression stroke of the pistons. The spark plug will ignite the fuel/air as it is compressed in the chamber to create combustion and push the piston down. In large engines, a distributor has traditionally been used to time the charge from each spark plug. A more recent advancement is the use of small computers to create more reliable synchronization.