Magneto – 1832

The magneto helped fire up the first generation of automobiles.

MagnetoMention the word "magneto" to a baby boomer and there is a good chance his or her first association will be the X-Men comic-book character. First appearing in 1963, Magneto is a powerful mutant with the ability to generate and control magnetism.

However, 132 years before Marvel comics introduced Magneto, the first magneto was built by French instrument-maker Hippolyte Pixii in 1832 – just one year after Michael Faraday's discovery of the principles of electromagnetic induction. Pixii's hand-crank operated magneto was the first practical generator of electrical current.

The magneto received a makeover in 1899 by automaker Daimler Phonix as part of the ignition system of internal combustion engines. The mechanism sends high levels of voltage to the spark plugs, which ignite the gasoline in the engine. At one time magnetos were incorporated in all automobiles, but now are mostly used in yard-work tools such as lawnmowers.

Although magnetos perform a complex function, the scientific basis behind the devices is elementary. It is simply a generator designed to produce occasional bursts of powerful current as opposed to the steady stream of electricity that comes from a battery. A magneto functions opposite of an electromagnet, in which an electrified coil of wire around an iron bar temporarily magnetizes the bar. In a magneto, a permanent magnet is moved past the bar, producing electric current in the coil. The principle advantages of a magneto are simplicity and reliability.

Some of the first telephones to go into commercial use featured a manually powered magneto to generate the voltage necessary to activate the bells of the phones using the same line.

Automotive magnetos evolved from considerable trial and error. At the beginning of the internal combustion era, a wide variety of implements were developed to trigger the ignition systems. One experimenter built a small trap door designed to move over an opening above the combustion compartment and release a fiery gas. That idea failed, as did an attempt by Karl Benz to utilize a vibrating ignition system.

Slowly but surely, incremental advances were made. The Daimler researchers used a hot clay hose feeding into the combustion compartment, a technique that proved effective, but the flames that provided heat for the hoses constituted a significant hazard. At one point, manufacturers tried building cars with battery ignition for starting and then changing to a magneto for continued operation of the vehicle. However, the use of dual units proved too complex and expensive for practical use.

The turning point in the effort to build a workable magneto came in 1906, when renowned inventor Charles Kettering became involved in the process. Working out of a former barn in Ohio, he developed the ignition structure that became the standard. The biggest problem to overcome was the unreliability of the points and spark plugs, as they tended to wear out prematurely. The Kettering model was able to solve these issues by supplying sparks at the precise intervals necessary with a high degree of accuracy and dependability. Once the magneto ignition system became reliable and efficient, cars began to move from the realm of curiosities into the mainstream transportation world.

Last modified on 10 December 2014