Insulation material introduction

What is insulating material? 

Insulating materials commonly used in electrical engineering can be divided into inorganic insulating materials, organic insulating materials, and mixed insulating materials according to their different chemical properties. Commonly used inorganic insulating materials include mica, asbestos, marble, porcelain, glass, sulfur, etc., which are mainly used as winding insulation of motors and electrical appliances, the base plate of switches and insulators the substrate and insulator of the switch, etc. Organic insulating materials include: gum, resin, rubber, cotton yarn, paper, hemp, rayon, etc., mostly used to manufacture insulating paint, winding wire

Covered insulators, etc. Mixed insulating materials are made of the above two materials after processing a variety of molding insulating materials, used as the base of electrical appliances, shells, etc.

Application of insulation materials 

The role of insulation materials is to isolate the electrically charged parts with different potentials in electrical equipment. Therefore, insulating materials should first have high insulation resistance and voltage strength, and can avoid leakage, breakdown, and other accidents. Secondly, the heat resistance should be good to avoid aging and deterioration due to long-term overheating; in addition, there should be good thermal conductivity, moisture and lightning resistance, and high mechanical strength, as well as easy processing and other characteristics.

Insulation Strength Introduction

According to the above requirements, the performance indicators of common insulating materials are insulation strength, tensile strength, specific gravity, expansion coefficient, etc.

Insulation strength: The higher the voltage added to the ends of the insulator, the greater the electric field force on the charges in the material, and the more likely it is that ionization collisions will occur, causing the insulator to break down.

The higher the voltage applied to the ends of the insulator, the greater the electric field force on the charges in the material, the more likely it is that ionization collisions will occur, causing the insulator to break down. The minimum voltage at which an insulator breaks down is called the breakdown voltage of the insulator. To make a 1 mm thick insulation material breakdown, the need to add the number of kilovolts is called the insulation strength of the insulation material, referred to as insulation strength. Since insulating materials have a certain insulation strength, various electrical equipment

The manufacturer of various electrical equipment, various safety appliances (electrician's pliers, test pens, insulating gloves, insulating rods, etc.), and various electrical materials, the manufacturer has specified a certain allowable use of electrical voltage, called the rated voltage. When using the voltage should not exceed its rated voltage value, in order to avoid accidents. 

Tensile strength: insulating material unit cross-sectional area can withstand the tensile force, for example, glass per square centimeter cross-sectional area can withstand the tensile force of 1400 Newton. Usually, the mica tape, mica roll will use glass fiber cloth as strength material.

Insulation material insulation performance and temperature have a close relationship. The higher the temperature, the poorer the insulation performance of the insulating material. To ensure the insulation strength, each insulation materials have an appropriate maximum allowable working temperature, below this temperature, can be used safely for a long time, beyond this temperature will be rapidly aging.

According to the degree of heat resistance, the insulating material is divided into Y, A, E, B, F, H, C, and other levels. For example, the maximum allowable working temperature of Class A insulation material is 105℃, most of the insulating materials in generally used distribution transformers and electric motors belong to Class A.