coil

A coil usually refers to a circular wire winding. Common coil applications include motors, inductors, transformers, and circular antennas. The coil in a circuit refers to an inductor. "Guide wires are wound one by one, and the wires are insulated from each other. The insulating tubes can be hollow or contain iron or magnetic particle cores, referred to as inductors.". Inductance can also be divided into fixed inductance and variable inductance, and fixed inductance coil is referred to as inductance or coil for short. Expressed in L, the units are Henry (H), milliHenry (mH), and microHenry (uH), with 1H=10 ^ 3mH=10 ^ 6uH.

Single-layer coils are made by winding insulated wires around a paper tube or bakelite skeleton one by one. Such as transistor radio medium wave antenna coils.

A single layer winding is a winding in which only one coil effective side is embedded in each stator slot, so its total number of coils is only half of the total number of slots in the motor. The advantage of a single layer winding is that the process is relatively simple with fewer windings; There is no interlayer insulation, so the utilization rate of the slot is improved; The single layer structure will not have interphase breakdown faults, etc. The disadvantage is that the electromagnetic waveform generated by the windings is not ideal, the motor has high iron loss and noise, and the starting performance is also slightly poor. Therefore, single layer windings are generally only used in small capacity asynchronous motors.