A field coil is a type of coil used in electrical machines, such as generators and motors, to produce a magnetic field.
It consists of a coil of wire wound around a central core of ferromagnetic material.
When an electrical current is passed through the wire, a magnetic field is generated in the core, which can then interact with the magnetic field produced by the armature or rotor to create motion.
Field coils are used in a wide range of applications, including electric cars, industrial machinery, and power plants.
They come in various sizes and shapes to suit different machine designs and operating conditions, and can be made from different materials, such as copper, aluminum, or silver.