Insulation system for prevention of corona discharge

Abstract

Methods and systems for preventing corona discharge are provided. In one embodiment, a housing forming a vacuum includes a coil conductor comprising a grounded conductive or semi-conductive layer that is molded over a primary insulation layer molded on coil conductor which limits the occurrence of voltage drop to the primary insulating layer is disclosed.

1 . A flywheel energy storage device comprising:
 a housing forming a vacuum, the housing containing:
 an insulation system for a coil conductor comprising:
 the coil conductor; 
 an over-molded insulated primary layer molded on the coil conductor; and 
 an over-molded conductive secondary layer on the primary layer, the secondary layer defining an outermost surface of the insulation system, wherein the secondary layer is grounded and limits an occurrence of voltage drop from the coil conductor to the insulated primary layer. 
 
   
     
     
         2 . The flywheel energy storage device of  claim 1 , wherein the primary layer is a thermoplastic material, a thermoset material, or combinations thereof. 
     
     
         3 . The flywheel energy storage device of  claim 1 , wherein the wherein the primary layer further comprises a thermoplastic primary layer and wherein the thermoplastic primary layer is fiber filled for mechanical strength. 
     
     
         4 . The flywheel energy storage device of  claim 1 , wherein the conductive secondary layer is a molded thermoplastic material, a thermoset material, or combinations thereof. 
     
     
         5 . The flywheel energy storage device of  claim 1 , wherein the conductive secondary layer is a plated or deposited material comprising nickel, zinc, or combinations thereof. 
     
     
         6 . The flywheel energy storage device of  claim 1 , wherein the conductivity of the conductive secondary layer is tuned to avoid high eddy current losses in a presence of time-varying currents and magnetic fields. 
     
     
         7 . A flywheel energy storage device comprising:
 a housing forming a vacuum, the housing containing:
 a coil conductor; 
 an over-molded insulated primary layer molded on the coil conductor; and 
 an over-molded conductive secondary layer on the primary layer, wherein the secondary layer is grounded and limits an occurrence of voltage drop from the coil conductor to the insulated primary layer. 
   
     
     
         8 . The flywheel energy storage device of  claim 7 , wherein the primary layer is a thermoplastic material, a thermoset material, or combinations thereof. 
     
     
         9 . The flywheel energy storage device of  claim 7 , wherein the wherein the primary layer further comprises a thermoplastic primary layer and wherein the thermoplastic primary layer is fiber filled for mechanical strength. 
     
     
         10 . The flywheel energy storage device of  claim 7 , wherein the conductive secondary layer is a molded thermoplastic material, a thermoset material, or combinations thereof. 
     
     
         11 . The flywheel energy storage device of  claim 7 , wherein the conductive secondary layer is a plated or deposited material comprising nickel, zinc, or combinations thereof. 
     
     
         12 . The flywheel energy storage device of  claim 7 , wherein the conductivity of the conductive secondary layer is tuned to avoid high eddy current losses in a presence of time-varying currents and magnetic fields. 
     
     
         13 . The flywheel energy storage device of  claim 7 , further comprising a grounded surface, a conducive clamp, a conductive support, a standoff, or combinations thereof in direct contact with the secondary layer for grounding the secondary layer and limiting the occurrence of the voltage drop from the coil conductor to the insulated primary layer. 
     
     
         14 . The flywheel energy storage device of  claim 7 , wherein the coil conductor and the primary layer comprise an exterior surface, and wherein the secondary layer covers substantially all of the exterior surface. 
     
     
         15 . The flywheel energy storage device of  claim 7 , wherein the primary layer is molded by an injection molding process. 
     
     
         16 . The flywheel energy storage device of  claim 7 , wherein the primary layer is molded by a vacuum drawn molding process. 
     
     
         17 . The flywheel energy storage device of  claim 7 , wherein the conductive secondary layer is deposited material on the primary layer. 
     
     
         18 . A flywheel energy storage device for a coil conductor that is adapted to limit corona discharge, the device comprising:
 a housing forming a vacuum, the housing containing:
 the coil conductor; 
 an insulated primary layer disposed over the coil conductor, wherein the insulated primary layer comprises an exterior surface; and 
 a conductive secondary layer disposed over substantially all of the exterior surface of the insulated primary layer, wherein the conductive secondary layer is grounded for limiting voltage drop of the coil conductor to the insulated primary layer. 
   
     
     
         19 . The device of  claim 18 , wherein the coil conductor comprises a non-uniform structure having air spaces therein. 
     
     
         20 . The device of  claim 18 , wherein the insulated primary layer, the conductive secondary layer, or combinations thereof, fills at least a portion of the vacuum and provides structural support to the coil conductor.