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US 5,708,555 AGranted
Surge arrester having controlled multiple current paths
AssigneeCooper Industries, Inc.
InventorsJonathan J. Woodworth, Jeffrey Joseph Kester, Thomas Carl Hartman
Life of this patent
Estimating the term…
Abstract
An improved surge arrester includes metal oxide varistors in series with spark gap assemblies arranged such that the MOV elements conduct the low magnitude, steady-state current through the arrester along a path that is separate and distinct from the path through which impulse current is conducted during an overvoltage.
Claims15
A surge arrester comprising:
- a resistive element having a longitudinal axis and a helical steady-state current path for conducting steady-state currents through said element to ground and having an impulse current path substantially parallel to said axis for conducting surge currents through said element to ground;
- wherein said resistive element comprises a spiral of nonlinear resistive material formed about an insulative core and including a spark gap between adjacent segments of said spiral, wherein said steady state current path is through said nonlinear resistive material and does not include said spark gap.
A surge arrester comprising:
- a resistive element having a central axis and a first face and a second face that is axially spaced apart from said first face by the thickness of said resistive element, each of said faces having a central region and a peripheral region surrounding said central region;
- a first electrode in electrical contact with said peripheral region of said first face, said first electrode having a central portion that is axially spaced apart from said central region of said first face along an axis parallel to said central axis to form a first spark gap between said first electrode and said central region of said first face;
- and
- a second electrode in electrical contact with said central region of said second face, said second electrode having a peripheral portion axially spaced apart from said peripheral region of said second face along an axis parallel to said central axis to form a second spark gap between said second electrode and said peripheral region of said second face between said second electrode and said peripheral region of said second face;
- such that said central axis passes through said central portion of said first electrode, said first spark gap, said central region of said first face, said resistive element and said central region of said second face.
2 more elements
A surge arrester, comprising:
- a plurality of nonlinear varistors stacked in columnar relationship and forming a varistor stack, each of said varistors including an upper and lower face and a central region and a peripheral region surrounding said central region on said faces;
- a plurality of series spark gaps each disposed between said central regions of adjacent varistors in said stack;
- and
- means for electrically connecting in series said peripheral regions of said varistors.
1 more element
A surge arrester comprising:
- an elongate insulative core;
- nonlinear resistive material disposed about said core;
- a spiraling channel formed in said resistive material;
- and
- terminal means in electrical contact within said resistive material at each end of said core.
2 more elements
A surge arrester, comprising:
- an insulative substrate;
- a plurality of adjacent segments of MOV material disposed about said substrate and electrically connected in series during steady state operation of the arrester;
- and
- a plurality of spark gaps between said adjacent segments of MOV material.
1 more element
A surge arrester, comprising:
- an insulative substrate;
- a plurality of adjacent segments of MOV material disposed about said substrate and electrically connected in series so as to form a steady state conduction path that is free of spark gaps;
- and
- a plurality of spark gaps between said adjacent segments of MOV material so as to form an impulse current path that includes said spark gaps.
1 more element
Dependencies are inferred from the claim text.