Method for producing a corona shield, fast-curing corona shield system, and electric machine

Abstract

The corona shield can be applied in electric machines in a faster manner by using radiation-cured materials.

What is claimed is: 
     
         1 . A method for producing a corona shield for electric machines comprising applying a curable material to the machine for shielding the electric machine; and curing the material on the machine by electromagnetic radiation. 
     
     
         2 . The method as claimed in  claim 1 , further comprising providing an electrically semiconducting filler in the curable material before the curing thereof. 
     
     
         3 . The method as claimed in  claim 2 , wherein the electrically semiconducting filler comprises silicon carbide or graphite. 
     
     
         4 . The method as claimed in  claim 2 , wherein a proportion of the semiconducting filler in the curable material is 30% by weight to 90% by weight. 
     
     
         5 . The method as claimed in  claim 1 , wherein the curable material that is cured by means of electromagnetic radiation comprises bisphenol A diglycidyl ether (BADGE), bisphenol F diglycidyl ether (BFDGE), 3,4-epoxycyclohexylmethyl-3′,4′-epoxy-cyclohexane carboxylate, phenol novolak, acrylate, urethane and/or ether. 
     
     
         6 . The method as claimed in  claim 1 , further comprising effecting a crosslinking by one or a plurality of initiators. 
     
     
         7 . The method as claimed in  claim 6 , wherein the initiator is operable to effect a crosslink as a result of a temperature increase. 
     
     
         8 . The method as claimed in  claim 1 , further comprising using secondary accelerators to vary the excitation of the initiators in the wavelength range. 
     
     
         9 . The method as claimed in  claim 1 , further comprising effecting the crosslinking of the curable material by free radical or cationic crosslinking mechanisms. 
     
     
         10 . The method as claimed in  claim 6 , further comprising using at least two different types of the initiators, wherein at least one type of the initiators brings about a crosslinking by means of heat and the other type of the initiators brings about a crosslinking by means of electromagnetic radiation. 
     
     
         11 . The method as claimed in  claim 6 , further comprising using a plurality of different initiators, which are activated in a wavelength-specific manner. 
     
     
         12 . The method as claimed in  claim 6 , wherein bis[4(diphenylsulfonium)phenyl]sulfide bishexafluoroantimonate is used as the initiator. 
     
     
         13 . The method as claimed in  claim 6 , using 2,4,6-trimethylbenzoyldiphenylphosphine oxide as the initiator. 
     
     
         14 . The method as claimed in  claim 6 , further comprising varying the initiators along the thickness of the curing material that is applied and is to be cured. 
     
     
         15 . The method as claimed in  claim 6 , wherein the compositions of at least one of the curing material to be cured and of the initiators are varied in the applied material to be cured over the thickness of the material to be cured. 
     
     
         16 . The method as claimed in  claim 6 , wherein the cured material in the corona shield has an irradiation surface which is exposed to be irradiated and has a base on an opposite side of the irradiation surface from the irradiation surface, and the method further comprising setting the concentration of the initiators in a region of an irradiation surface of the curing material to be lower in concentration than at the base of the curing material opposite the irradiation surface. 
     
     
         17 . The method as claimed in  claim 1 , wherein the curing is by UV radiation. 
     
     
         18 . The method as claimed in  claim 6 , further comprising using monomers as the curable material. 
     
     
         19 . The method as claimed in  claim 14 , wherein the thickness of the curing material is varied on account of a wavelength-specific activation of the initiators corresponding to variations of the composition of the initiators or of the concentration of the initiator or initiators. 
     
     
         20 . A method for producing a corona shield for an electric machine comprising applying a curable material to a part of the machine for shielding the electric machine; and curing the material on the machine by heat.