Some Indicators That Insulation Materials Need
Insulating paper is typically a sheet of material formed from plant fibers, mineral fibers, synthetic fibers, or mixtures thereof, by depositing fibers on a paper machine through water or other media. Insulating paper has high tear strength, low elongation and good insulation. It is widely used as insulation material in motors, cables, capacitors and transformers. It is also an insulating material for laminates, composites and prepregs.
Insulating materials such as DMD insulating papers are subjected to various mechanical stresses in many cases, and are constant, vibrating, and have thermal expansion and contraction cycles. These stresses can cause creep damage or fatigue damage. The insulating materials used by insulating paper manufacturers in outdoor use are directly exposed to sunlight and will also age under the action of ultraviolet rays. The insulating materials used in nuclear reactors and X-ray devices are subjected to radiation and are aged. The moisture of the insulating material will increase the conductance and increase the loss. Water also dissolves many substances and accelerates various chemical reactions that lead to aging. Acid, ozone, etc. can also cause chemical aging. For some insulating materials, such as polyethylene, dendrites can occur at very low electric field strengths due to the presence of moisture (see solid dielectric breakdown). In addition, in the warm tropical region, the insulating material is also damaged by various microorganisms, so-called microbial aging.
Thermal stability is an important indicator of insulating paper and is a major factor in the generation of low-voltage insulation aging, which determines its service life. Under normal operating conditions, the electric field strength has only a slight effect on the insulation aging process. When the insulating paper is used in a relatively high temperature environment for a long time, it will become brittle due to heat aging, and gradually lose its mechanical and electrical properties.