Below is a list of Permanent Magnet Motor manufacturers from San Mateo, California. A permanent magnet motor is a type of electric motor that uses permanent magnets in its rotor assemblies in order to provide motion. The difference between a permanent magnet and a non-permanent magnet is that a permanent magnet retains its magnetism indefinitely, or until finally over-powered by external forces such as vibration, corrosion and interfering magnetic fields.