A Permanent Magnet Alternator (PMA) is a type of electrical generator that uses a permanent magnet as the rotor, which rotates within a stator coil to produce an alternating current (AC) output. The permanent magnet eliminates the need for an external power source to generate the magnetic field, making the system more efficient and reliable.

In a PMA, the permanent magnet is typically made of a rare-earth material, such as neodymium, and is attached to the rotor shaft. As the rotor rotates, the magnetic field induces an electromotive force (EMF) in the stator coil, generating an AC output. The output frequency and voltage of the PMA depend on the speed of rotation and the design of the stator coil.

PMAs are widely used due to their high efficiency, compact design, and low maintenance requirements. They are often used to generate power for electrical systems, such as those found on aircraft, where reliability and efficiency are critical.