Insulation structures for use in the insulation space and with the phase barrier insulation of an electrical inductive apparatus. The insulation structures include at least one layer of spaced, vertically-extending spacer members which is surrounded on both sides by layers of electrical insulating sheet material. The insulation structures are disposed in movable relation with the adjacent windings and phase barrier insulation, thereby allowing relative movement between the windings and the insulation structures during a short circuit.

Insulation structures for electrical inductive apparatus

The present invention relates to a transformer with a low eddy current and magnetic hysteresis loss and a manufacturing method thereof. The transformer with the low eddy current and magnetic hysteresis loss comprises a core, a primary coil and a secondary coil, an insulating paper, and an insulation material, wherein the core is made of an amorphous material or ferrite, the insulating paper and the insulation material have low permittivity and a high insulation rate regardless of insulation class, an interlayer insulation thickness of the coils is maintained to be greater than 1 mm and smaller than 4mm, and an insulation interval between the core and the coil is maintained to be greater than 5mm and smaller than 10 mm.

Transformer with low eddy current and magnetic hysteresis loss and manufacturing method thereof

An improved low voltage winding for dry insulated transformer has its windings resin encapsulated. The winding is constructed with flexible sheet conductors wound coincident with an insulating sheet material. Insulating spacers provide a means to form air channels in the windings during the coil forming process. A sealant is applied to openings at the lower ends and along vertical seams of the coil prior to the resin impregnation and encapsulation process. This will prevent drainage of the resin during a curing cycle. The result is a coil that exhibits high short circuit protection due to the tightly bond sheet conductors which will prevent movement of the conductors during short circuit conditions and also increases the radial compressive strength of the coil.

A strip wound induction coil with improved heat transfer and short circuit withstandability

Electrical winding assembly constructed by (A) winding an electrical conductor into a plurality of radially-spaced layers about an axis, (B) disposing electrical insulating sheet material, which has dry, heat-reactive resin material disposed at discrete areas on at least one side thereof, between the layers of the electrical conductor, (C) applying a slurry formed of solid, heat-reactive resin particles suspended in a non-aqueous liquid carrier, wherein the liquid is chemically inert for the resin particles suspended therein so as not to dissolve or enter into a reaction with the resin, at predetermined locations between certain of the layers of the electrical insulative material and the electrical conductor and (D) heating the electrical winding assembly at a predetermined temperature for a predetermined period of time sufficient to volatize the non-aqueous liquid carrier and to cause the resin on the electrical insulative material and in the slurry to soften and form cohesive bonds between adjacent layers of the electrical insulative material and the electrical conductor as it polymerizes to a solid state.

Method of constructing an electrical winding assembly

A wideband audio output transformer for use with a push-pull vacuum tube amplifier using a multifilar ribbon in which primary windings and secondary windings coexist. The multifilar ribbon is wound continuously around a common core side by side to form successive layers. The primary windings are connected in series by turning the multifilar ribbon after the layers of multifilar ribbon have been wound and connecting the trailing end of the multifilar ribbon to the beginning end of the multifilar ribbon. Two additional wires are added in parallel with wires of the primary windings in the multifilar ribbon to redistribute the effective capacitance throughout the windings. The winding scheme eliminates the signal imbalance of an output transformer with a balanced push-pull primary winding and an unbalanced secondary winding at high frequencies. The winding scheme also increases the coupling between the first half primary, the second half primary and the secondary windings without compromising transformer performance at high frequencies. The secondary windings are connected in parallel to obtain the proper turns ratio for the transformer. The center tap of the balanced push-pull primary winding and one side of the unbalanced secondary winding is connected to AC ground.

Wideband audio output transformer with high frequency balanced winding

Distribution transformer having inner and outer low-voltage winding sections and a high-voltage winding section disposed therebetween. Insulation structures separate the various winding sections and include a relatively small thickness of solid insulating material and a liquid dielectric duct. Some of the solid insulating material is axially extended to increase the creep resistance of the winding. The insulation structures are also void of any metallic electrostatic shield or any other member which would hamper adequate processing of the insulation structure during the construction of the transformer.

John P. McInerney

Papers

Insulated transformer windings