Mechanical test of electrical insulating materials
Insulation bars must undergo an AC withstand voltage test every year. Unqualified insulation rods shall be scrapped and destroyed immediately. They shall not be reduced in standard use, and shall not be put together with qualified insulation rods. ……
Insulation bars must undergo an AC withstand voltage test every year. Unqualified insulation rods shall be scrapped and destroyed immediately. They shall not be reduced in standard use, and shall not be put together with qualified insulation rods. When storing, choose a well ventilated, clean and dry place, and hang the square on the special gate bar, which is managed by special personnel. The insulation plate should not be in contact with the wall to prevent it from getting wet.
Once the surface of the insulating rod is damaged or damp, it should be treated and dried in time. Damage to the surface of the shaft should not be tangled with ribbons such as wire or plastic tape. When drying, it is best to use the natural drying method of sunlight. After handling and drying, the gate must be tested before it can be reused. An insulating rod is generally composed of three sections. When storing or carrying, the sections should be disassembled and then the exposed threads should be put into special special tool bags with their ends facing upwards to prevent scratches on the surface of the shaft or damage to the threads.
Silicone resin combined with less alkali glass cloth, greatly improved the heat rating. Polyvinyl formal for the paint base made of enameled wire to open up the broad prospects of enameled wire, replacing the silk envelope and yarn envelope. The thickness of the polyester film is only several tens of micrometers, and it is used instead of the original paper and cloth, so that the technical and economic indicators of motors and electrical appliances are greatly improved. Polyaramid fiber paper, polyester film and polyimide film are used together to make the heat insulation grade of the motor slot insulation become class F and class H respectively. Elastomeric materials have similar developments, such as heat-resistant silicone rubber, oil-resistant nitrile rubber, and subsequent fluororubber, ethylene-propylene rubber, and the like.
In a strong electric field, the insulation material is destroyed, and the loss of insulation performance becomes a conductive state, which is called breakdown. The breakdown voltage is called the breakdown voltage (dielectric strength). The electrical strength is the quotient of the distance between the voltage and the voltage applied to the two electrodes when a breakdown occurs under specified conditions, that is, the breakdown voltage per unit thickness. For insulating materials, the higher the breakdown voltage and the electrical strength, the better.
In the tensile test, the maximum tensile stress to which the specimen is subjected. It is the most widely used and representative test of the mechanical properties of insulating materials. Refers to the ability of the insulating material to resist combustion when it comes into contact with the flame or to prevent it from continuing to burn when leaving the flame. With the increasing application of insulating materials, the requirements for its anti-combustibility are more important. People use various means to improve and improve the anti-combustibility of insulating materials. The higher the flame resistance, the better its safety.