Principle of operation - Genset

It is best if you read The Magnetism first.

Some irons, when dug up, attract other metals. They are called MAGNETS. The reason that they are magnetic is that their DOMAINS are aligned.

One end of a bar magnet is the NORTH POLE, the other end the SOUTH POLE.

A rule of magnetism is that LIKE POLES REPEL, UNLIKE POLES ATTRACT.
North attracts South and repels North etc.

The North pointer on a compass is actually a South pole since it is attracted by the North pole of the earth.

A magnet is surrounded by an invisible MAGNETIC FIELD made of magnetic LINES OF FORCE.
These lines of force can be made visible by covering a magnet with a sheet of paper and sprinkling iron filings on the paper.

The lines of force run from north to south.

Lines of force pass through all materials including insulators. They pass through some more easily than others. These are said to have a lower RELUCTANCE. Iron has a lower reluctance than air.
The lines of force prefer to pass through lower reluctance materials.

PERMANENT magnets are made of steel or steel alloys. Brass, copper and aluminum do not magnetize.

When a piece of wire is moved through a magnetic field, a voltage and current is induced in the wire.

The same effect is obtained if the wire is stationary and the field is moved.

The direction of current flow is determined by the direction of the field, and the direction of the movement.

The amplitude of the voltage is determined by the rate at which the wire cuts the lines of force.
Increasing the density of the field or increasing the speed of the wire therefore increases the voltage.

This principle is used in the electric generator, where a coil is rotated in a magnetic field to generate electricity.

It is also used in the moving coil microphone, where sound causes a coil to vibrate in a magnetic field, generating voltages which represent the sound waves.

The Electric Motor Principle is related. It relies on passing a current through a wire in a magnetic field to provide movement.

In 1820, Danish physicist Hans Christian Oersted (1777–1851) discovered that an electric current created a magnetic field around it. French physicist André Marie Amperè (1775–1836) then found that a coil of wire with current running through it behaved just like a magnet.

In about 1831, English physicist Michael Faraday (1791–1867) discovered the scientific principle on which generators operate: electromagnetic induction. By reversing the work of Oersted and extending the work of Amperè, Faraday reasoned that if a current running through a coiled wire could produce a magnetic field, then a magnetic field could induce (generate) a current of electricity in a coil of wire. By moving a magnet back and forth in or near a coil of wire, he created an electrical current without any other source of voltage feeding the wire.