Field magnet refers to a magnet used to produce a magnetic field in a device. It may be a permanent magnet or an electromagnet. When the field magnet is an electromagnet, it is referred to as a field coil.
Although the term usually refers to magnets used in motors and generators, it may refer to magnets used in any of the following devices:
Alternator Cathode ray tube Dynamo Electric motor Electrical generator Fusion reactor Loudspeaker Maglev trains Magnetic Separator Magneto Mass spectrometer Metal detector MRI scanner Particle accelerator Read/write head Relay Solenoid Stepping switch Tape head
See also
Rotor (electric) Stator