A coil sheet includes a conductor layer, a thermally resistant organic insulating layer, a thermosetting adhesive layer in a B-stage state, and a base layer, such that the conductor layer and the insulating layer are bonded to the base layer with the adhesive layer. A coil is formed of a laminate sheet including a conductor layer, an insulating layer, and an adhesive layer of the coil sheet which are released from the base layer thereof, wherein the laminate sheet is wound around a specific axis a plurality of times, and the adhesive layer is thermally cured.

A method produces a coil sheet from an initial coil sheet in which a conductor layer, a thermally resistant insulating layer, a thermosetting, uncured adhesive layer, and a base layer are stacked in this order. The method includes a first cutting step of cutting the conductor layer into a predetermined shape through etching, and a second cutting step of cutting, after the first cutting step, the insulating layer and the adhesive layer into the predetermined shape through etching.

A coil device includes two core members, one of which is E-shaped. The E-shaped core member has left and right side faces, and a center leg that extends in a vertical direction. A conducting wire is wound around a core, the core being composed of the two core members arranged to face each other in the vertical direction with a gap between the two core members. The conducting wire is wound around the center leg. First and second heat-sinking plates made of metal are bent so as to be in contact with upper and side faces of the core. The first and second plates are arranged so that first edges of the plates are placed left-right symmetrically with respect to the core with a gap between the edges. Second edges of the plates are in contact with a metal heat-sinking board where the core is placed.

A coil electrode 4 provided in a coil component 1a includes a plurality of inner metal pins 5a arranged on an inner peripheral side of a coil core 3, a plurality of outer metal pins 5b arranged on an outer peripheral side of the coil core 3 to form a plurality of pairs with the inner metal pins 5a, a plurality of lower wiring patterns 7 that connect lower ends of the inner metal pins 5a and the outer metal pins 5b in the pairs, and a plurality of upper wiring patterns 6 that connect upper ends of the outer metal pins 5b to upper ends of inner metal pins 5a adjacent to the inner metal pins 5a that form the pairs with the outer metal pins 5b.

A transformer cooling system is described. The transformer cooling system includes a dry transformer and a housing for the dry transformer. The dry transformer includes a core including a leg. Additionally, the dry transformer includes a winding body arranged around the leg. Further, a cooling channel extending in a direction of a longitudinal axis of the winding body is provided. Additionally, the transformer cooling system includes a heat exchanger adapted to dissipate heat from the housing. Further, the transformer cooling system includes a flow generating device arranged in the housing for providing a cooling flow in the cooling channel. The flow generating device is connected to the heat exchanger.

A conductive structure for an electromagnetic device includes a conductive sheet and a plurality of protrusions. The conductive sheet includes two electrical connection terminals. The protrusions are arranged between the electrical connection terminals. The protrusions include a support. The support is connected to the conductive sheet. Adjacent two of the protrusions define a first heat dissipation passage.

An object of the present invention is to provide a small-sized and highly heat-dissipative reactor and a DC-DC converter using the reactor. A reactor according to the present invention includes a plate bus bar, a core, and a heat sink. The core includes a middle leg portion. The heat sink cools the plate bus bar. The plate bus bar is formed such that a winding axis of a winding including the plate bus bar passes through the middle leg portion. A main surface of the plate bus bar is disposed in parallel with a direction of the winding axis and thermally connected to the heat sink via an insulating layer.

A core (X1) has a shape of a rectangular loop having sides (A1 to A4). The sides (A1, A3) are opposed to each other. The sides (A2, A4) are opposed to each other. A winding (w11) is wound around the core (X1) on the side (A2). A winding (w12) is wound around the core (X1) on the side (A4). A winding (w21) is wound around the core (X1) on the side (A2). A winding (w22) is wound around the core (X1) on the side (A4). The windings (w11, w12) are wound around the core (X1) at equal distances from the side (A1). The windings (w21, w22) are wound around the core (X1) at equal distances from the side (A1). The windings (w11, w12) are connected in series or in parallel to each other. The windings (w21, w22) are connected in series or in parallel to each other.

A coil device includes a coil unit for stowing a coil part, and a heat dissipation unit thermally connected to the coil unit. The heat dissipation unit has a heat dissipation body, a heat dissipation fin movable relative to the heat dissipation body, and a fin drive mechanism for driving the heat dissipation fin. The heat dissipation unit has a heat dissipation configuration in which the heat dissipation fin projects from the heat dissipation body in a direction intersecting a winding axis, and a stowed configuration in which the heat dissipation fin is stowed in the heat dissipation body.

An isolated converter reduced in size compared with a conventional isolated converter and having a high heat dissipation characteristic is provided. The isolated converter includes a multilayer substrate having a first through hole and a magnetic core partially passing through the first through hole. The multilayer substrate includes a first conductor pattern formed at a position overlapping the magnetic core on a second surface when viewed from a direction orthogonal to a first surface, a second conductor pattern formed between the first surface and the second surface at a position overlapping the magnetic core and the first conductor pattern when viewed from the direction orthogonal to the first surface, at least one thermal conductive member formed on the first conductor pattern and having a portion disposed between the multilayer substrate and the magnetic core, and an electric insulating layer electrically insulating the first conductor pattern from the second conductor pattern.