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US 6,396,676 B1Granted
Electrical surge arresters
AssigneeBowthrope Industries Limited
InventorsRodney Meredith Doone, Patrick George Short
Life of this patent
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AssigneeBowthrope Industries Limited
InventorsRodney Meredith Doone, Patrick George Short
Estimating the term…
An electrical surge arrester is manufactured by securing a stack of metal oxide varistor blocks between end terminations by passing a rod through through-holes in the varistor blocks and securing the ends of the rod to the end terminations. The through-holes are larger than the rod cross-section and a silicone rubber material is injected into the void which otherwise would exist between the rod and the interior surfaces of the through-holes in the varistor blocks. The silicone rubber material is also moulded around the exterior of the stacked varistor blocks and forms a shedded external housing for the arrester. The silicone rubber coatings on the varistor block internal and external surfaces effects a passivation function and means that the passivation coatings normally provided on the surfaces of varistor blocks by their manufacturers at significant cost can be omitted.
An electrical surge arrester comprising a stack of varistor elements retained between end terminations by means of an electrically insulating rod passing through through-holes in the varistor elements and secured to said end terminations, the through-holes being larger than a cross-section of said rod and a molded plastic material filling a void that otherwise would exist between the rod and the varistor elements and extending around the external surfaces of the stacked varistor blocks, the varistor elements being devoid of passivation coatings on their internal and external surfaces, and said molded plastic material being selected to provide a passivation function.
A method of manufacturing an electrical surge arrester, said method comprising the steps of
Dependencies are inferred from the claim text.