coilwinding

Coil winding is the process of forming an electrical winding by wrapping conducting wire around a core or former to create inductors, transformers, electromagnets, and related devices. The arrangement of turns determines inductance, resistance, magnetic coupling, and voltage transformation.

Conductors used are typically copper, with aluminum as an alternative in some applications. Magnet wires are enamel-insulated to allow many turns in compact spaces; common coatings include polyurethane and polyamide. Additional insulation such as tapes, varnishes, or potting compounds may be applied. Windings may be built around ferrite cores, laminated iron cores, or exist as air-core configurations.

Winding forms include bobbins, tubes, and various core geometries. Winding methods range from manual, hand-guided winding to automatic machines. Techniques include layer winding, where turns are laid in successive layers, and random winding, as well as bifilar or multi-section windings for specific electrical characteristics. For high-frequency or low losses, litz wire or multi-strand conductors may be employed to reduce skin and proximity effects. Winding equipment often uses payoff and take-up spindles, tension control, and precision forming to maintain tolerances.

Applications span transformers (power, distribution, and audio), inductors and chokes, motors and solenoids, relays, sensors, and electromagnetic devices. Design considerations include target inductance or turns ratio, operating voltage and current, insulation class and temperature rating, wire gauge, and the number of layers. Parasitic effects such as stray capacitance, leakage inductance, and inter-winding coupling must be managed.

Quality and safety measures involve verifying turn count, DC resistance, insulation resistance, and high-potential testing, along with conforming to insulation coordination and thermal management requirements. Proper handling and curing of insulation, along with appropriate potting or varnishing, ensure durability and reliability.