High-voltage insulators having multiple materials
High-voltage insulators are disclosed that are capable of handling diverse requirements, such as providing high standoff voltages, high temperature cycling, and the ability to withstand flexural stress. One high-voltage insulator includes a first piece formed from a first material, a second piece formed from a second material, and an interface section where the first piece contacts with and forms a seal with the second piece. The interface includes a first groove located that accommodates a first gasket, sets of matching threads on the first and second pieces. The interface section further accommodates a second gasket. In this multi-piece high-voltage insulator, the first material can have a first set of flexural, heat resistance, and electrical standoff characteristics suitable for a first environment, and the second material can have a second set of flexural, heat resistance and electrical standoff characteristics suitable for a second environment.
1. A method for assembling a high-voltage insulator that includes a top piece and a bottom piece, matching threads on the top and bottom pieces, and at least two gaskets, the method comprising:
assembling the top and bottom pieces without including the gaskets;
placing an alignment marker on the assembled insulator that crosses a boundary of the top and bottom pieces to identify aligned locations of the assembled insulator;
disassembling the top and bottom pieces;
applying high-voltage grease, gel or lubricant to the at least two gaskets;
assembling the insulator with the at least two gaskets in place;
tightening the insulator until a portion of the alignment marker on the top piece matches a portion of the alignment marker on the bottom piece, wherein the matching threads, the at least two gaskets and the high-voltage grease, gel or lubricant produce a substantially void-free joint between the top and bottom pieces.
2. The method of claim 1 , wherein the high-voltage insulator includes a bottom, a middle and a top gasket, each located at an axially and longitudinally offset location within the high-voltage insulator with respect to one another, and wherein assembling the insulator with the at least two gaskets in place includes placing the bottom, the middle and the top gaskets at the corresponding grooves or ledges on the bottom piece and allowing the middle gasket to deform prior to the bottom and top gaskets.
3. The method of claim 1 , wherein the matching threads form a continuous path and have mated rounded edges.
4. The method of claim 1 , wherein the matching threads have a sinusoidal profile.
5. The method of claim 1 , wherein a start point of a first set of the matching threads matches an end point of a second set of matching threads to form a complete thread around a circumference of an interface section.
6. The method of claim 1 , wherein:
the top section is formed from a first material and the bottom section is formed from a second material,
the second material is capable of withstanding higher temperatures than the first material,
the first material is more readily shaped via machining operations compared to the second material, and
the second material has a higher dielectric constant than the first material.
7. The method of claim 1 , wherein a first gasket of the at least two gaskets has a smaller volume than a first groove located on the bottom piece to accommodate the first gasket, and a height in the longitudinal direction of the first gasket is larger than a height of the first groove.
8. The method of claim 1 , wherein the substantially void-free joint between the top and bottom pieces is formed without a need for an epoxy.
9. The method of claim 1 , wherein the top and the bottom pieces each have an axially symmetric structure, and the bottom piece is formed of a material that is different from a material of the bottom piece.
10. The method of claim 1 , wherein the top piece material includes poly-ether-ether-ketone (PEEK) and the bottom piece material includes machinable ceramic.
11. The method of claim 1 , wherein the matching threads are configured to match one another within 0.002 inch or less.