Insulation material is also known as dielectric. In contrast to conductive materials, it is virtually non-conductive in the application of DC voltages, except for the very small so-called leakage current passing through.

The main functions of insulating materials for heat shrinkable tubes in various motors, electrical appliances, switches, wires, cables and radios are:

First, the conductive body and other parts of the insulation of each other;

Second, it separates the conductors of different potentials;

Third, it is used to improve the potential gradient in the high voltage electric field;

IV, it guarantees that capacitors and other electrical appliances to achieve the required capacitance.

In the structure of electrical products, double-walled heat shrinkable sleeves are often used, and insulating materials occupy an extremely important position. This is due to:

(1) in modern electricians more and more widely used high-voltage transmission and unit capacity of larger motors, electrical appliances, at the same time, electrical equipment in the tropics, cold zones, plateaus, oceans, high altitude, underground and other places of use continue to expand;

(2) The emergence of electrical appliances for atomic power stations, high-frequency and UHF radio transmission and reception devices, as well as radio locators and television institutions.

Therefore, it is possible to further improve the accuracy and safety of its work only under the condition of using new insulating materials. You can find out the logo heat shrinkable casing.

The insulating materials actually applied in the electrician are divided into two types, natural and synthetic, according to their origin. The former includes cotton yarn, cloth, natural resin, natural rubber, vegetable oil and petroleum products, etc., the latter includes glass fiber, synthetic fiber, synthetic film and resin. According to its shape, there are four categories of gas, liquid, elastomer and solid. Among the commonly used insulating materials, the variety of solids is the most. According to its chemical molecular structure, there are two types of organic and inorganic, the chemical molecular structure of the former contains carbon element C, the latter does not contain carbon elements.

The main performance requirements of different types of motors and electrical appliances for insulating materials are as follows:

1. High Voltage Motor

In high voltage motor, the electric shock piercing strength of insulating material should be high and the media loss should be small. In addition, because the high voltage motor has electromagnetic and mechanical vibration in operation, it is required that its insulation system has good stiffness, integrity and thermal elasticity, and the dielectric coefficients of different insulating materials in the insulating structure are preferably close or equal, so that the voltage distribution on the insulator does not differ greatly, and has the ability to resist atmospheric overvoltage and internal overvoltage.

New high-pressure, high-capacity generators and motors (whose insulation is Class B or f), in the use of powder mica, bisphenol A epoxy resin or lipid ring epoxy resin (or linear phenolic epoxy resin) insulation, coupled with the appropriate anti-corona treatment and insulation process (winding), can better meet the above requirements.

2. Low voltage motors and electrical appliances for electric power

In general low-voltage motor, electrical appliances, by the dielectric properties of insulating materials directly caused by the problem is less, but due to its lack of mechanical strength, as well as temperature rise and other factors caused by the inter-turn and interphase short-circuit, ground insulation breakdown and other accidents more; therefore, insulating materials are required to withstand various forms of mechanical load and are durable.

3. DC Motors, electrical appliances

In general DC motors and electrical appliances, the working condition of the insulation system is relatively good because of the constant direction and size of the current. However, in metallurgy, coal mine, ship, traction and other systems used in high temperature or high speed motor, in order to solve the insulation site heat, high tide, strong vibration or the role of centrifugal force, but the use of silicone resin, polyurethane and aromatic polyester and other combination of insulating materials.

热缩管绝缘材料在电工行业中用途(一）

绝缘材料又称电介质。它与导电材料相反，在施加直流电压下，除有极微小的所谓泄漏电流通过外，实际上是不导电的。

热缩管的绝缘材料在各种电机、电器、开关、电线、电缆及无线电等装置中的主要作用是:

第一，使导电体跟其他部分互相绝缘;

第二，由它把不同电位的导体分隔开来；

第三，用来改善高压电场中的电位梯度;

第四，由它保证电容器等电器达到所需要的电容量。

在电工产品的结构中，经常会用到双壁热缩套管，绝缘材料占有极其重要的地位。这是由于:

(1)在现代电工中越来越广泛地采用高压输电和单位容量较大的电机、电器，同时电工装备在热带、寒带、高原、海洋、高空、地下等使用场所不断扩大;

(2)原子能电站、高频和超高频无线电发射和接收装置的电器，以及无线电定位器和电视机构等的出现。

因此，只有在使用新型绝缘材料的条件下，才有可能进一步提高其工作的准确和安全程度。你可以了解一下标识热缩套管。

在电工中实际应用的绝缘材料，按其来源分，有天然和人工合成的两类。前者包括棉纱、布、天然树脂、天然橡胶、植物油及石油类产品等;后者包括玻璃纤维、合成纤维、合成薄膜和树脂等。按其形态分，有气体、液体、弹性体和固体四类。在常用的绝缘材料中，以固体的品种为最多。按其化学分子结构分，有有机和无机的两类，前者的化学分子结构中含有碳元素C，后者不含碳元素。

不同类型的电机、电器，对绝缘材料的主要性能要求如下:

1.高压电机

在高压电机中，绝缘材料的电击穿强度应高，介质损耗要小。此外，由于高压电机在运转时有电磁和机械震动，故要求其绝缘系统具有良好的刚度、整体性和热弹性;在绝缘结构中的不同绝缘材料的介电系数，最好是接近或相等，使绝缘体上的电压分布不致于相差悬殊，并具有抗大气过电压及内过电压的能力。

新型的高压、大容量发电机和电动机(其绝缘是B级或F级)，在采用粉云母、双酚A型环氧树脂或脂环族环氧树脂(或线型酚醛环氧树脂)绝缘时，加上合适的防电晕处理和绝缘工艺(对绕组)，能较好地满足上述要求。

2.电力用低压电机、电器

在一般低压电机、电器中，由绝缘材料介电性能直接引起的问题较少，但是由于其机械强度不足，以及温度升高等因素造成的匝间和相间短路、对地绝缘被击穿等事故较多;因此，要求绝缘材料能承受各种形式的机械负荷，并经久耐用。

3.直流电机、电器

在一般直流电机、电器中，由于其电流方向和大小不变，绝缘系统的工作情况比较良好。但在冶金、煤矿、船舶、牵引等系统中用的高温或高转速电机中，为解决绝缘部位发热高、潮化严重、震动厉害或承受离心力作用的问题，而要采用有机硅树脂、聚酸亚胺以及芳香聚ft胺等组合绝缘材料。