It depends on the corona (grading) ring design and manufacturing process. Die cast are usually 380, sand and permanent mold 356 or A356, and fabricated rings are usually made from 6061 thin wall tubing or pipe that is formed and welded; with appropriate brackets and other mounting provisions.
No. It just has to be conductive and bonded to the energized (or grounded) electrode which it is grading. Their function is to increase or expand and reshape the geometry of energized (or grounded) end caps, etc. and smooth the electrostatic field, thereby reducing the voltage gradient on those surfaces to a level below the critical ionization gradient of the surrounding air or other media.
More properly, they are voltage grading rings that also serve to grade the voltage of the insulator, surge arrester, bus clamp, etc. and reduce the overall voltage stress by increasing the coupled capacitance to the surrounding voltage field.
Aluminum is most commonly used for corona rings because of its light weight, relative ease of casting or fabrication, cost and availability but other metals can also be used.
What is the Material of Corona Ring ?
Re: What is the Material of Corona Ring ?
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