Alternator

An alternator is a device that converts motion into alternating Current (or AC).

Alternators come in many shapes and sizes.

One variety uses magnets to make the magnetic field that is required to make an alternator work, these are so called 'Permanent Magnet Alternators' (or PMA's).

Another variety uses an electromagnet, these are known as 'Field Excited Alternators'.

The second variety is usually found in cars and trucks, the first is by far the most common choice for smaller windmills.