Hitachi, Ltd.

Takeshi Hakamada

Toshikazu Narahara

Ikushi Kano

Hideyo Hirata

Misao Soma

Masahiko Sakai

Yoshiharu Karasawa

Tomoya Tsunoda

Shinichi Toyoda

Toshio Katoh

Mituo Kashimura

Yoshiyuki Suda

Masao Matsui

Misao Souma

An insulation system for winding of electric rotating machines having thermal resistance of class H or more and excellent adhesiveness between a conductor and an insulating layer and resistance to thermal stress can be produced by wrapping a plurality of layers of an insulating tape or sheet having thermal resistance of class H or more around a winding conductor, impregnating the thus treated winding conductor with a solventless varnish consisting essentially of 1 equivalent of an epoxy compound containing at least two vicinal epoxy groups, more than one equivalent of an organic polyisocyanate, and then heating the inpregnated winding conductor at a temperature above 60.degree. C. for a time sufficient to form and cure a resin containing as recurring units at least two isocyanurate rings directly bonded to one another through the residue of the polyisocyanate and two oxazolidone rings directly bonded to each other through the residue of the polyepoxide in the presence of 0.01-10% by weight of a catalyst which forms the isocyanurate rings and oxazolidone rings based on the total amount of the polyepoxide and polyisocyanate.

Insulation system for winding of electric rotating machines and process

Electric windings comprising an electric conductor and a plurality of cured insulating layers wrapping around the conductor, said cured insulating layers being obtained by bonding two or more insulating materials with a binder solution containing a mixture of a condensation polymerization type silicone resin containing hydroxyl groups in the molecule and an addition polymerization type silicone resin to form a composite insulating material, wrapping the composite insulating material around the conductor, impregnating the wrapped composite insulating material with an impregnating varnish of an epoxy-isocyanate resin and curing the impregnated composite insulating material, have excellent water resistance in addition to excellent thermal resistance, and mechanical properties.

Electric windings and production thereof characterized by the use of a

A method for producing electrically insulated apparatus, which may be used in windings for rotary electric machines, for example, an induction motor, synchronous machines, DC machines or stationary induction apparatus, for example, transformers, and the product produced thereby comprising an electric conductor and an insulating layer formed around the electric conductor, wherein said insulating layer contains a resin having excellent permeability for the gas generated in the layer, e.g., a silicone resin, and a resin having excellent adhesive force in an appropriate blending ratio in order to impart excellent thermal resistance to the electrically insulated apparatus.

Method for electrically insulating an electrically conducting article

An insulator for covering electric conductors is used to cover, for the purpose of providing insulation, lead wires of the coils in rotary electric machines or stationary induction motors or conductors for connecting various electrical machinery and apparatus. The insulator is comprised of a flexible plastic film tube provided with a soft material on its inner surface. Such a construction prevents the insulation from being damaged even if the electric conductor has corners or bends or even if an external force is applied to the electric conductor because the soft material is compressed and deformed to absorb the applied force.

Insulator for covering electric conductors

An electromagnetic apparatus in which a semiconductive liner of which at least one side is processed by mold releasing material is provided between the winding embedded in the slots of an iron core and the wall of the slot, and the remainder of the slots is filled with adhesive. The liner employed prevents the winding from adhering to the wall of the slot with the result that the insulating layer of winding is not damaged during thermal cycling and also corona discharge is prevented.

Insulated windings provided with a mould releasing material

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Hitachi, Japan

Takeshi Hakamada