A reactor includes an outer peripheral iron core and at least three iron-core coils that contact or are connected to an inner surface of the outer peripheral iron core. Each of the iron-core coils includes iron cores and coils wound onto the iron cores. The reactor further includes an external cooling unit disposed outside the outer peripheral iron core, to cool the outer peripheral iron core.

The present invention is directed to a method of estimating an overheating temperature of an oil-immersed electric appliance in which ester oil is used as insulating oil. The overheating temperature is estimated based on a first concentration ratio representing a concentration ratio between two types of gas components contained in the ester oil and a second concentration ratio representing a concentration ratio between other two types of gas components contained in the ester oil. The first concentration ratio and the second concentration ratio are selected from a concentration ratio between acetylene and ethane, a concentration ratio between acetylene and hydrogen, a concentration ratio between acetylene and methane, and a concentration ratio between acetylene and ethylene.

A cooling device for an electromagnetic interference filter is disclosed. The cooling device includes a housing. The housing includes a main body having a cavity shaped to receive the electromagnetic interference filter and one or more cooling channels surrounding at least a portion of the cavity in the main body of the housing. The one or more cooling channels define one or more flow paths that are contained completely within the housing. The housing also includes an inlet port and an outlet port. The one or more cooling channels fluidly connect the inlet port to the outlet port, and a cooling medium is configured to flow into the inlet port, through the one or more cooling channels, and exit the housing through the outlet port.

A reactor cooling structure includes: a plurality of reactors that are stacked on one another, each reactor including a coil configured to produce magnetic flux when energized; and a cooling mechanism that cools the plurality of reactors, wherein each of the reactors has an exterior member that has: heat radiation surfaces respectively on both sides of the corresponding one of the reactors in a stacking direction of the stacked reactors i.e. a first direction, the heat radiation surfaces of the exterior member of each of the reactors being arranged to cool the coil of the corresponding one of the reactors; the cooling mechanism includes a cooling flow path for directly cooling the first and second heat radiation surfaces of the exterior member of each of the reactors by a refrigerant.

A wireless charging device with a heat dissipation function is provided. The wireless charging device includes a case, a wireless charging assembly and a working fluid. The case includes an accommodation space. The wireless charging assembly is disposed in the accommodation space. The wireless charging assembly includes a circuit board, a coil coupled to the circuit board and a connector coupled to the circuit board. The working fluid is disposed in the accommodation space in the case. The circuit board and the coil of the wireless charging assembly are immersed in the working fluid.

Provided is a transformer oil that has high environmental compatibility and is expected to be further improved in transformer cooling properties. The transformer oil is a transformer oil prepared by mixing a plant oil and a silicone oil and containing no mineral oil, in which a volume ratio of the plant oil to the silicone oil is 3:7 to 7:3 and magnetic particles (for example, temperature-sensitive magnetic particles) are dispersed.

Provided is a static electric induction arrangement including: a static electric induction device arranged in a static electric induction device tank; an accessory tank including at least one opening configured to receive an accessory therein; the static electric induction device tank and the accessory tank are intended to be filled with dielectric fluid and are connected via a fluid connection, an upper portion of a cross section of the fluid connection, is located at a first height, the arrangement comprises a heat exchanger connected to the device tank, the device tank includes an outlet that is arranged to lead the dielectric fluid to the heat exchanger and an inlet that is arranged to return the dielectric fluid from the heat exchanger.

A dielectric fluid and coolant for electrical apparatuses such as transformers. In one embodiment, the fluid contains more than 25% biobased base oil, such as a biobased hydrocarbon oil, which has a molecular weight greater than 300 g/mol and less than 595 g/mol. The biobased base oil may optionally be blended with other oils, such as mineral oils and vegetable oils.

A vehicle is provided with a transmission and an inductor assembly that is mounted within a chamber of the transmission. The inductor assembly includes a coil, a core and an insulator having first and second portions that are oriented toward each other. Each portion includes a base, a support extending from the base, and a spool extending transversely from the support to engage the other portion. Each spool includes an external surface for supporting the coil and a cavity extending therethrough for receiving the core.

Core-coil devices operate by electromagnetic induction and include inductors, transformers, and electromagnets. Cooled core-coil devices include a magnetic core having a channel through it, and a coil wound around the core. Cooled core-coil devices additionally include a coolant loop that carries ferrofluid coolant through the channel and forms a loop with the channel that extends outside the core. Ferrofluid coolant circulates in the loop without a pump due to a thermo-magnetic response to the device's thermal and magnetic field gradients and thereby cools the core while simultaneously adding to the device's inductance.