PMA (Permanent Magnet Alternator)

Each Muirhead Engine Control Sub-Assembly has been designed, engineered and manufactured by in-house teams. Units have specific applications and meet the high performance, high quality and high reliability specifications demanded within the aerospace industry.

Detailed below are the ranges of operation for a PMA and some if its typical performance characteristics.

Applications

PMAs convert the mechanical rotation of a shaft into electrical power. In the simplest of forms a PMA would consist of a high-energy permanent magnet rotor that rotates within a wound copper stator. PMAs are located in general on the auxiliary gearbox of an engine where the rotation of the gearbox shaft is used to rotate the rotor of the PMA. The electrical output of a PMA is in AC form and is proportional to the engine speed.

The output power from a PMA can be used in a multitude of ways, such as continuous power for an aircraft’s Fly-by-Wire system, or providing back up power for the Electronic Engine Control System (EEC). The stator consists of a power winding and two electrically and mechanically isolated speed windings. The windings will supply independent AC voltages through a sleeved cable bundle to the EEC. The rotor is built from samarium cobalt magnets bonded to a hub and sleeved.