The quality and degree of insulation performance of materials. It is mainly reflected by the resistance (called insulation resistance) of the insulation material. The insulation resistance value is the ratio of the DC voltage on the processed insulation to the current of the insulation (called leakage current). Adequate insulation resistance. It can limit the leakage current to a very small range to prevent equipment accidents or electric shock accidents caused by leakage current.
The insulation resistance is composed of volume resistance and surface resistance. The product resistance is the resistance value of the current passing through the insulation thickness, and the surface resistance is the resistance value of the current passing through the insulation surface. The insulation resistance commonly referred to refers to the total resistance of the insulating material, which is the parallel value of the volume resistance and surface resistance. Correspondingly. The resistivity of insulating materials can also be divided into volume resistivity and surface resistivity.
There are many types of insulation materials, generally divided into:
1) Gas insulation materials. Commonly used include air and sulfur hexafluoride.
2) Liquid insulation material. Insulating mineral oil extracted from petroleum crude oil, synthetic oils such as dodecylbenzene, polybutadiene, silicone oil, trichlorobiphenyl and castor oil are commonly used.
3) Solid insulation material. Commonly used include resin insulation paint, insulation tape, and deposited powder; Insulating fiber products such as insulating paper and cardboard; Insulating fiber products such as insulating paint cloth, insulating paint pipes, and binding tapes; Insulated mica products; Polyimide films, composites and tapes for electrical purposes; Laminated products for electrical purposes; Plastic and rubber for electrical purposes; Glass, ceramics, etc.
Each insulation material has its ultimate heat resistance temperature, and when this limit temperature is exceeded, its aging will intensify. The lifespan of electrical equipment is shortened. In electrical technology, insulation structures and systems in electric motors and appliances are often classified according to their heat resistance level.