Brief analysis of coil insulation structure

Insulation structure of coils

Insulation structure is formed by combining the same kind of insulating materials or several kinds of insulating materials together through a specific process is called insulation structure. It mainly involves turn-to-turn insulation, ground-to-ground insulation, outer insulation and, in the case of three-phase motors, phase-to-phase insulation.

● Turn-to-turn insulation

Turn-to-turn insulation refers to the insulation between turns of the same coil, which serves to separate conductors with different potentials in the motor winding from each other to avoid turn-to-turn short circuits. For enameled wire winding, turn-to-turn insulation is the surface of the electromagnetic wire insulating paint, while the wire, mica wire, is a specific insulating material and insulating adhesive bonded to the composite insulating material.

In general, the turn-to-turn insulation only by the electromagnetic wire itself with the insulation, such as enameled wire, single glass wire wrapped or double glass wire wrapped wire. Glass wire wrapped enameled wire, polyimide film sintered wire, etc. with its own insulation. Turn-to-turn insulation is the most important and usually weak insulation in the motor insulation structure, so in the design of turn-to-turn insulation should pay attention to the choice of materials, in the manufacturing process must pay attention to, the wire should be smooth, no flying edges, burrs, etc., can not be mechanically strained turn-to-turn insulation.

Ground insulation

Ground insulation is the main insulation outside the coil. It is mainly subject to the rated voltage of the motor or possible overvoltage, and its working voltage is high, so its electrical, mechanical and thermal properties must meet the requirements of the motor operating conditions. The thickness of the ground insulation generally depends on the rated working voltage of the motor and the electrical and mechanical properties of the insulating material, the higher the rated voltage of the motor, the more layers of ground insulation wrapping, or the thicker the thickness of the paint film.

● Outer insulation

Outer insulation refers to the insulation outside the main insulation of the coil. And its role is mainly to protect the main insulation from mechanical strain and make the whole coil solid and tight, the main insulation plays a reinforcing role, most of the outsourcing insulation using glass tape.

● Phase-to-phase insulation

Phase-to-phase insulation is unique to three-phase motors, and is the insulation between phases. For loose embedded windings, phase-to-phase blocks are used to separate the two phases, and insulating hoses are also used at the ends of the windings; the phase-to-phase insulation of hard windings is realized by using plate insulating materials or relative distance spaces.