Abstract: A wall structure for insulating the exterior surface of a high voltage coil having Roebeled windings is provided that comprises an inner insulating layer formed from a hardenable epoxy material for surrounding the coil and filling void spaces on the surface of the coil created by the Roebeled windings, a ground wall layer surrounding the inner layer for grounding the wall structure, and a semiconductive layer formed from a carbon filled epoxy material integrally molded around the outer surface of the inner insulating layer for reducing the electric stress across the insulating layer and in particular across any voids remaining after the insulative layer has been applied over the Roebeled windings on the exterior of the coil. The improved wall structure advantageously increases the lifespan of high voltage coils by reducing the electric stress across the inner moulding layer, thereby reducing the probability that damaging electric arcing will ever occur in any void spaces present in this layer.

Abstract: A process and apparatus are disclosed for step-molding elongated work pieces, such as generator components. A heated press includes a cooling box attached thereto, separated by a thermal insulating gasket. As a first portion of the work piece is being heat cured, a second portion extending adjacent the heated press is placed within the cooling box to prevent its being cured from residual heat of the press. After the first portion has been cured, the second portion is sequentially placed within the heated press. In this manner, the entire elongated work piece is cured and inadvertent "bumps" in the cured work piece are prevented to form the component to its desired shape.

Abstract: An improved method and apparatus for preventing electrical shorts between sets of stator coil headers and accompanying connections is disclosed in which a reinforced, non-conducting cover is fitted over a pair of stator coil headers, or a stator coil header and an adjacent phase connector. Thereafter, the cavity formed by the fitted cover can be filled with an insulating, solidifying or polymerizing material or resin. Use of such an apparatus insulates the entire header apparatus and prevents any accidental shorting between sets of stator coil ends.

Abstract: A plurality of connector members are provided, each of which is shaped to fit between two adjacent strands in a column of strands on a stator winding (i.e., by manual insertion). Each connector member has a first side provided with an electrically conductive material and a second side provided with an electrically insulating material. An electrically conductive lead is electrically connected to the electrically conductive material on an associated connector member. In this manner, a plurality of electrically conductive leads are connected to an associated plurality of connector members. A plug or receptacle is provided at the opposite end of the electrically conductive leads with respect to the end connected to the connector members. Securing means are provided for pressing the strands against the connector members interposed therebetween in order to insure a conductive connection between each strand and the conductive material of a connector member.

Abstract: High voltage testing of stator coils having grounded insulation, end turns with ungrounded insulation, and uninsulated terminals is conducted by placing a non-conductive, preferably transparent and flexible tube over each end turn and injecting a gas, such as silicon hexaflouride SF.sub.6, having a higher breakdown voltage than air into the tube at one end, so that it flows down the tube around the end turn and out the other end. If desired, the tube can be sealed at the inlet end or both ends by flexible sleeves which are secured snugly about the end turns. Also optionally, the tube can be supported by an adjustable stand so that it does not touch the end turn.

Abstract: An end turn support structure is disclosed which permits it to be constructed with varying, preselected coefficients of expansion along its length. This characteristic allows it to expand in a similar manner to the end turns which it supports. This structure also comprises conformable members and external support apparatus that provide a means for firmly attaching the end turns to the support structure and the support structure to the stator frame.

Abstract: A magnetic wedge is made by preparing a composition of a thermosetting resin system and magnetizable particles, placing the composition in a mold, vibrating the mold at least until air bubbles are no longer evolved from the composition, curing the composition, and fabricating the lower portion of the cured composition into the shape desired for the wedge. The vibration removes air and compacts the particles which results in a wedge having overall superior physical and magnetic properties.

Abstract: A construction is provided for the stator coil ends of large dynamoelectric machines such as turbine generators of the inner-cooled type which effectively insulates the ends of the gas coils and mechanically reinforces them without interfering with ventilation. An insulating vent cap is applied over the ventilating tubes at each end of each conductor. The vent caps have a soft, uncured portion and are fitted to the conductor and then impregnated with a resin and cured in place to obtain a good fit of the cap on the conductor. The complete coil ends and connections are then covered with an insulating and mechanically reinforcing tape.

Abstract: A magnetic wedge is made by preparing a composition of a thermosetting resin system and magnetizable particles, placing the composition in a mold, vibrating the mold at least until air bubbles are no longer evolved from the composition, curing the composition, and fabricating the lower portion of the cured composition into the shape desired for the wedge. The vibration removes air and compacts the particles which results in a wedge having overall superior physical and magnetic properties.

Abstract: A conductor is provided for large dynamo-electric machines, such as turbine generators, having a header at the end of the conductor for connection in a liquid-cooling system and having means for strengthening and reinforcing the conductor in the region immediately adjacent the header to reduce the excessive strains which may occur in this region and greatly reduce the possibility of failures of the conductor or of individual strands of the conductor.

Abstract: An article, such as a mica wrapped coil, a dynamo-electric machine component containing mica wrapped coils, or a metal substrate, is insulated by: (A) applying wet epoxy resin to the article, (B) contacting the wet epoxy resin with a titanate solution, for a time effective to form a resin impervious, gelled epoxy skin on the surface of the epoxy resin, where the titanate solution consists essentially of organo-titanate and an organic, non-polar solvent, where the weight ratio of organo-titanate:organic non-polar solvent is from 1:2.5 to 1:99, and (C) curing the epoxy resin.