In electrical engineering, coil winding is the manufacture of electromagnetic coils. Coils are used as components of circuits, and to provide the magnetic field of motors, transformers, and generators, and in the manufacture of loudspeakers and microphones. The shape and dimensions of a winding are designed to fulfill the particular purpose. Parameters such as inductance, Q factor, insulation strength, and strength of the desired magnetic field greatly influence the design of coil windings. Coil winding can be structured into several groups regarding the type and geometry of the wound coil. Mass production of electromagnetic coils relies on automated machinery.

Rotor and stator

Corresponding laminations for the rotor and the stator are stamped from the same sheet of electrical steel. The rotor has 40 slots and teeth. The stator has 36 slots and teeth. A very narrow gap separates the rotor and stator. The teeth widen and the slots narrow at the gap. The wide part is called a tooth shoe.

Laminations

The rotor and stator are both assembled from a stack of laminations stamped from sheets of electrical steel, typically 1 mm thick. The laminations are designed to minimize eddy currents, which would otherwise waste energy and create heat.

Slots and teeth

Windings consist of insulated conductors, which pass through slots cut along the axis of the stator. The spaces between the slots are called teeth. The shape of the slots and teeth depends upon the design of the electric machine. Slots may be rectangular, they may taper, they may be circular, etc.The wider part at the end of the tooth is called a tooth shoe.

Some authors use the term "groove" to mean the same thing as slot. In this article, the term groove refers to the indentations between parallel conductors in a layer of a winding.

Poles

Pole means magnetic pole, and poles always come in pairs, usually referred to as "North" and "south." Poles may be physical objects in fixed places, or poles may be virtual objects moving as the machine operates. A pole may be a single piece of magnetic material, or a pole may be distributed over multiple teeth.