Magneto

magneto: see generator.

---

magneto

Permanent-magnet alternating generator used mainly to produce electrical current for the ignition system in various types of internal-combustion engines, such as aircraft, marine, tractor, and motorcycle engines. The main parts of a magneto are a permanent-magnet rotor, a primary winding of a small number of turns of coarse wire, a secondary winding with a large number of turns of fine wire, a cam-type circuit breaker, and a capacitor. As the rotor turns, it produces a current in the primary winding, charging the capacitor. The cam breaks the circuit, and the magnetic field around the primary winding collapses. The capacitor releases its stored current into the primary winding, causing a reversed magnetic field. The collapse and reversal of the magnetic field produce a current in the secondary winding that is sent to the spark plugs.

---

magneto

a small electric generator in which the magnetic field is produced by a permanent magnet, esp one for providing the spark in an internal-combustion engine

---

magneto [mag′nēd·ō]

(electricity)

An alternating-current generator that uses one or more permanent magnets to produce its magnetic field; frequently used as a source of ignition energy on tractor, marine, industrial, and aviation engines. Also known as magnetoelectric generator.

---

Magneto 

(magneto ringer), a manually operated magneto-electric device used in telephones to send call signals and disconnect signals in manually operated rural telephone exchanges. A magneto generates an alternating current with a frequency of 18–21 hertz, a voltage of 60–70 volts, and a power output of 3.8 watts into a load resistance of 2.5 kiloohms.

Two types of magnetos are made: one type has two stationary rectangular magnets, a rotating (wound) armature, a reduction gear, and current-collecting springs; the other has a stationary (wound) armature and a rotating ring-shaped multipole magnet. The required current frequency is produced if the crank is rotated at a rate of 3–3.5 revolutions per sec.

REFERENCE

Telefoniia, 2nd ed. Edited by V.A. Novikov. Moscow, 1967.

---

Magneto 

a magnetoelectric AC generator (usually in combi-nation with an induction coil) designed to produce an electric discharge between the electrodes of a spark plug, which ignites the gas mixture in the cylinders of an internal-combustion engine. Magnetos have been used in the ignition systems of aircraft, tractor, automobile, motorcycle, and other engines; since the 1960’s they have virtually gone out of use.