Magneto
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.
For redundancy, virtually all piston engine aircraft are fitted with two magneto systems, each supplying power to one of two spark plugs in each cylinder.
The machine built by Hippolyte Pixii in 1832 used a rotating permanent magnet to induce alternating voltage in two fixed coils.
[4] Such electroplating expanded to become an important aspect of the Birmingham toy industry, the manufacture of buttons, buckles and similar small metal items.
To achieve an adequate output power, magneto generators used many more poles; usually sixteen, from eight horseshoe magnets arranged in a ring.
The Belgian electrical engineer Floris Nollet (1794–1853) became particularly known for this type of arc lighting generator and founded the British-French company Société de l'Alliance to manufacture them.
The lighthouse keepers of the time, usually semi-retired sailors, were not mechanically or electrically skilled enough to maintain these more complex machines.
The fixed excitation of a magneto made it difficult to control its terminal voltage or reactive power production when operating on a synchronized grid.
[11][12] The generators use rotating neodymium rare-earth magnets with a three-phase stator and a bridge rectifier to produce direct current (DC).
This current either directly pumps water, is stored in batteries, or drives a mains inverter that can supply the commercial electricity grid.
In large sizes, from the 100 kW to MW range, the machines developed for modern wind turbines are termed permanent magnet synchronous generators.
Most commonly, a small magneto, termed a bottle dynamo, rubs against the tire of the bicycle and generates power as the wheel turns.
Magnetos adapted to produce impulses of high voltage for spark plugs are used in the ignition systems of spark-ignition piston engines.
Motor sport vehicles such as motorcycles and snowmobiles may use magnetos because they are lighter in weight than an ignition system relying on a battery.
Small internal combustion engines used for lawn mowers, chain saws, portable pumps and similar applications use magnetos for economy and weight reduction.
The development of modern rare-earth magnets makes the simple magneto alternator a more practical proposition as a power generator, as these permit a greatly increased field strength.
As the magnets are compact and of light weight, they generally form the rotor, so the output windings can be placed on the stator, avoiding the need for brushgear.
