Epoxy Resin Insulators
Specifications of insulating material :
For long , porcelian was the sole material applied for insulation purposes , this material however show following disadvantages. It is highly fragile , incorporation of metalic parts in case of porcelain is very difficult and problematic , poor dimensional accuracy and rather big shortcomings regarding design and shape giving possibilities. After 1945 , with the appearance of synthetic materials on the world market , changes came fast,however it is due to epoxy resin ” ARALDITE ” that supporting compact designing at last possible as well as high geometrical accuracy and great ease of processing.
Mechanical strength :
The impact strength of porcelain insulators to that of Epoxy Resin are a few times less . It is due to this high impact strength that ” ARALDITE ” cast resin insulators show an all round better performance under short circuit conditions as well as during transport and installation and assembly works.
Since the dimensional accuracy in Epoxy resin during process is very high there is no need of extra work for dimensional correction or surface glazing.
For having the same mechanical strength when potential differences are equally applied , the diameter of epoxy resin insulator can be reduced to half and the weight of it , one third to half that of porcelain insulators.
Because of not having glaze on the outside surface , there is no possibility of surface crack or fracture.
Thanks to the high adhesion of ” ARALDITE ” epoxy resins , the metalic parts can be casted into the insulators providing one solid component , eliminating extra caps or holders , making it possible that the whole length of insulator is used for insulating purposes.
Electrical Strength :
1- The dielectric strength of epoxy resin is high , also because of non organic filler in the resin , a very good arc resistance is given.
2- Since the metalic parts can be casted into the insulator providing one solid component , as well as better installation , in the high voltages they prevent to discharge corona and so the creep distance can be increased.
Thus the overall heght of insulators can be decreased when the voltages are equally applied.
3- In the case of high surface arching the epoxy resin insulator due to not having glaze and non organic filler , will not breakdown so that the eventual arching can only effect the surface and may easily be cleaned off , this property of epoxy resin insulators thus provides long service life , low maintance and short blackouts.