Abstract: A ballast choke coil constructed with more than two winding coils assembled on laminate cores (LC) being held together firmly by a bracket (M1) in the manner of simulating the toroidal structure created more space for increasing the number of winding turn of the coil or alternatively allow for increase of wire size. Total number of winding turns that is needed to achieve the required inductance is divided to several coils. The new structure utilizes only half of the laminate material for producing a simple ballast choke coil unit that is similar performance to the existing fluorescent lamp ballast choke coil available in the market. Even though two units of coil (WC) are used in the construction of this ballast choke coil, the wire total weight that is used to produce a unit of ballast need not be increased.

Abstract: There is provided an inductive coupler for coupling a signal to a conductor. The inductive coupler includes (a) a magnetic core having an aperture through which the conductor is routed, (b) a winding wound around a portion of the magnetic core, where the signal is coupled between the winding and the conductor via the magnetic core, and (c) a member that maintains an electrical connection between the magnetic core and the conductor.

Abstract: It is possible to provide a transformer core which can be mounted on a coil having both ends connected to a substrate or the like and can simplify the step for arranging an adhesive layer and suppress fluctuation of a magnetic gap. The transformer core (1) includes: a rectangular spacer (5, 20) having a region where a first convex portion (10, 21) is formed on the four sides of one of the surfaces as a unitary block and the first convex portion is not provided at least at a part of a pair of two opposing sides; and a sheet-shaped adhesive layer (6) bonded to a region where at least the first convex portion is not provided on the one of the surfaces of the spacer and connecting a soft ferrite core (4) to the spacer.

Abstract: An inductance element (1) includes a doughnut-shaped magnetic core (2) having a wound body or a stacked body of a magnetic ribbon, a bottomed container (3) in which the doughnut-shaped magnetic core (2) is housed, and a conductive lead portion (5) inserted into a hollow section of the doughnut-shaped magnetic core (2) housed in the bottomed container (3). An open section of the bottomed container (3) is covered with an adhesive portion (4) which integrally fixes the doughnut-shaped magnetic core (2), the bottomed container (3) and the conductive lead portion (5). The adhesive portion (4) is entered into a gap between the doughnut-shaped magnetic core (2) and the bottomed container (3) and a gap between the bottomed container (3) and the conductive lead portion (5) in a range of 5 to 50% in average to a thickness of the doughnut-shaped magnetic core (2).

Abstract: A ferrite sheet includes a ferrite sintered body capable of being in direct and sufficiently close contact with a signal cable and has good noise removal properties. The ferrite sheet includes a flexible sheet having a foldable portion, a plurality of ferrite sintered bodies located in a region other than the foldable portion on the flexible sheet, an elastic body arranged around the ferrite sintered bodies on the flexible sheet, and an adhesive layer arranged on the elastic body such that the elastic body is bonded to itself when the flexible sheet is bent along the foldable portion.

Abstract: An electrical induction device for high voltage applications, of the type comprising a magnetic core which has at least one leg and is operatively coupled to a supporting structure, at least one inner winding which is arranged around said leg and has a first rated voltage, at least one outer winding which is arranged around said at least one inner winding and has a second rated voltage; and electrically insulating means, wherein said at least one inner winding comprises a plurality of substantially concentric turns formed by a sheet of electrically conducting material which is spirally wound, and in that said electrically insulating means comprise at least one layer of electrically insulating material which is arranged between mutually facing surfaces of said concentric turns, and first shaped insulating means which edge, at least partially, at least one of the upper and lower external rims of said inner winding.

Abstract: Manufacturing of miniaturised three-dimensional electric components are presented, as well as components manufactured by the methods. The manufacturing methods comprise micro-replication of at least one master structure, e.g. via a mould structure, in at least one polymer layer onto which layer at least one conductive path is provided.

Abstract: A housing can accommodate an electronic component. An outer wall of the housing forms a flat contact wall in which contact areas for connecting the housing to an interconnect device are arranged.

Abstract: The present invention discloses a transformer, mounted on a circuit board, including a winding set having a bobbin, a primary winding and a secondary winding, wherein the primary and the secondary windings are wound on the bobbin, and the primary winding has at least a first output terminal; a magnetic core set including a first magnetic core and a second magnetic core, wherein the winding set is sandwiched in between the first and the second magnetic cores; and an insulation base including an accommodation space and at least a pin, wherein the winding set and the magnetic core set are accommodated in the accommodation space, and the first output terminal of the primary winding is connected with the pin for further electrically connecting to the circuit board.

Abstract: Described herein are improved configurations for a resonator enclosure for wireless high power transfer that includes a support plate, a sheet of good conductor positioned on one side of the support plate, a separator piece for maintaining a separation distance between the resonator and the sheet of good conductor, and a cover of a non-lossy material covering the resonator, the separator, the sheet of good conductor and attached to the support plate, wherein the size of the sheet of good conductor is larger than the size of the resonator.

Abstract: An ignition coil of a dual ignition type that can prevent outputs from becoming unbalanced due to a difference in floating capacitance on wiring that connects secondary output terminals and ignition plugs together, thus realizing balanced outputs. A coil assembly housed in a housing as a coil case has a primary coil and secondary coils disposed concentrically with the primary coil. The secondary coils are comprised of two coils wound in opposite directions with the center of winding width being a boundary. The center of the winding width of the primary coil is shifted from the center of the winding width of the secondary coils by a predetermined width so as to balance outputs from the two secondary coils. A casting material is filled into a gap between the housing and the coil assembly and gaps which the coil assembly has.

Abstract: An ignition coil is inserted into a plughole of an engine. The ignition coil includes a coil case accommodating a primary coil and a secondary coil, and extending to define a cylindrical mount portion on a high voltage side. The mount portion includes a high voltage terminal conductive with the secondary coil. A coil spring conducts the high voltage terminal with the sparkplug. A plug cap has a circumferential portion attached to the mount portion. The plug cap circumferentially surrounds the high voltage terminal, the coil spring, and the sparkplug. The mount portion has a substantially annular space communicating with an inner gap in the coil case, and charged with an infilling resin to have a first resin high voltage end located on the high voltage side with respect to a low voltage end of the circumferential portion of the plug cap on a low voltage side.

Abstract: A choke module (100) for an insulative housing (2) includes a first and a second walls (23, 24) defining a first and a second receiving cavities (28, 29); a first set of contact terminals (4) arranged in the first wall, a second set of contact terminals (4) arranged in the second wall, a third set of contact terminals (5) disposed in the partition, a paddle board (6) having a number of conductive traces and attached to the insulative housing to interconnect the first and third set of contact terminals, a number of chokes (8) wound with wires which interconnects the first and second sets of contact terminals. The first and second contact terminal has a first and a second soldering portion (42) extending out of the housing and a first and a second mating portion (41) at the first wall.

Abstract: An ignition coil includes a coil body, a plug connection portion protruding from the coil body, and a connector for electrically connecting the ignition coil to an outside. In the coil body, a primary coil is arranged on an inner peripheral side of a secondary coil, and a center core is arranged on an inner peripheral side of the primary coil. The secondary coil includes a secondary electric wire having thereon an insulating film, wound around an outer periphery of a resinous secondary spool. Furthermore, the connector is formed integrally with an end of the secondary spool in an axial direction.

Abstract: A transformer including an insulating housing, a first bobbin, a primary coil, a second bobbin, a secondary coil, a first core and a second core is provided. The insulating housing has a first chamber and a second chamber separated from the first chamber, wherein two apertures of the first chamber and the second chamber are respectively disposed on two opposite side-walls of the insulating housing. The first bobbin has a first through hole disposed in the first chamber. The primary coil is surrounded on the first bobbin. The second bobbin has a second through hole disposed in the second chamber. The secondary coil is surrounded on the second bobbin. The first core is inserted to the first through hole and the second through hole. The first core and the second core are coupled together to form a magnetic loop.

Abstract: A method for conserving space in a circuit or on a printed circuit board by integrating a plurality of electronic components so that the plurality of electronic components collectively take up a smaller amount of space on a substrate than the plurality of electronic components would if the plurality of electronic components were not integrated.

Abstract: A reception unit is provided including a receiver coil for the contactless transfer of electric energy. The receiver coil includes a plurality of flux guiding elements (16a, 16b) that are made of a highly permeable material and that are designed to concentrate the field lines. The flux guiding elements (16a, 16b) form a continuous molded part that is embodied in a base body (18) and that is combined with the base body to form a component that can be completely prefabricated. The molded part is produced by casting and the base body (18) is used as a casting mold.

Abstract: There is provided an inductive coupler. The inductive coupler includes (a) a housing having an aperture that extends lengthwise through the housing, a gap that extends lengthwise along a side of the housing, and a flexible region that enables the gap to be opened or closed, wherein the gap, when opened, permits the inductive coupler to be installed on a conductor by having the conductor routed through the aperture. The inductive coupler also includes (b) a magnetic core; and (c) a winding wound around a portion of the magnetic core. The magnetic core and the winding are secured to the housing such that a position of the magnetic core and a position of the winding are maintained relative to one another. The inductive coupler, when installed on the conductor, couples a signal between the conductor and the winding via the magnetic core.

Abstract: An air cooled core mounted ignition system for gas turbine engine applications is provided. The ignition system includes an ignition exciter component directly mechanically and electrically connected to an igniter component. The housing member of the exciter component includes an air plenum configured to receive bleed air from the engine fan or compressor sections of the turbine engine, or other source. The bleed air provides a relatively low temperature air source for the purpose of cooling of the exciter. As such, the exciter component can be directly secured to the igniter, thereby eliminating the need for an ignition lead.

Abstract: A plastic case surrounds a primary winding of a multicharge ignition system, and has a rib in which the high voltage end is routed back to the low voltage end, so that the low and high voltage ends can be closely juxtaposed with each other while advantageously permitting the primary winding to have one and only one winding layer to reduce resistance and size. The rib of the case extends into the slot of the magnetic shields of the winding.

Abstract: An ignition coil configured for electrical communication with a spark plug of an internal combustion engine has a primary spool and a secondary spool. The primary spool has a bore and an outer surface with a low-voltage winding supported thereon. The secondary spool has a cavity with a magnetic core received therein and a substantially cylindrical outer surface. The secondary spool is received at least partially in the bore of the primary spool. A high-voltage winding is supported on the outer surface of the secondary spool. The high-voltage winding has discrete winding sectors spaced from one another along a length of the secondary spool.

Abstract: A device is disclosed for connecting electrical devices. The device may include a transformer, a connector post with a nut, and a conductor. The conductor may be positioned from the transformer to an opening of the connector post. The conductor may be a metal plate. The nut may clamp the device lead to the conductor to electrically connect them. The nut may be retained on the post, even when unsecured from the post.

Abstract: A noise filter available for various cable widths and capable of being easily attached to a cable. The noise filter has a first core having both ends to which first and second holding members and are attached, and a second core having both ends to which third and fourth holding members and are attached. First and second contacting portions and are formed on a first facing surface at the first core. Third and fourth contacting portions are formed on a second facing surface at the second core. When the first and second contacting portions are brought into contact with the third and fourth contacting portions an insertion hole is provided between the first and second contacting portions and between the first and second facing surfaces. The first and third holding members are coupled to each other by a retaining portion and retaining projection. The second and fourth holding members and are coupled to each other by a hinge portion.

Abstract: An electromagnetic actuating apparatus having an elongated actuating element (3) which forms an engagement area (11) at the end, can be moved by the force of a coil device (13), (which is provided in a stationary manner) and has a permanent magnet (4), in places, which are designed to interact with a stationary core area (7), with a stationary bearing element (8) which acts as a yoke, being provided axially opposite the core area (7) for the actuating element (3), which is in the form of a piston at least in places, and with the coil device (13) having at least one coil winding (17) which is arranged on a mount (15) and whose winding wires (22, 23) are passed to contact elements (20, 21) and are electrically conductively connected to them, with the connections (24, 25) between the winding wires (22, 23) and the contact elements (20, 21) being arranged with vibration or oscillation damping with respect to the mount (15).

Abstract: A transformer board is disclosed. In some embodiments, the transformer board includes a base, a circuit board, a transformer having a first and second winding, a first and a second connector, a ribbon cable and a nonconductive fill material. The base has a recess within which the circuit board is positioned. The transformer is mechanically coupled to the circuit board. The first connector is configured to electrically couple to transducers within a pressure boundary of an ultrasonic flow meter and is electrically coupled to the second winding of the transformer. The ribbon cable is electrically coupled between the first winding of the transformer and the second connector. The nonconductive fill material is contained by the recess and encases the circuit board, the transformer, the coupling of the first connector to the second winding of the transformer, and the coupling of the ribbon cable to the first winding of the transformer.

Abstract: A filter includes a coil leading structure and at least one coil. The coil leading structure includes a board and at least one pin. The pin is disposed at a side of the board and formed integrally with the board as a monolithic piece. The core is disposed on the board and has at least one end to be coupled with the pin.

Abstract: The invention can provide a miniaturized noise filter. The noise filter for reducing noise comprises a coil with a conductive wire (2) wound around a core (1); a case (6) formed of an insulating material receiving the coil; a bracket (8) of a magnetic material forming a flux path of magnetic flux generated from the coil, which places the case thereon, which has a pair of end plates (12a, 12b) disposed opposite to both ends of the core of the coil respectively through a gap of a predetermined distance, and which has a bottom plate (8a) disposed between the pair of the end plates; and an input/output terminal (3a, 3b) for the coil.

Abstract: An inductive coupler assembly has a first coupler having a first support structure and plural discrete first ferromagnetic segments supported by the first support structure, and a second coupler to inductively couple to the first coupler, the second coupler having a second support structure and plural discrete ferromagnetic segments supported by the second support structure.

Abstract: An ignition coil includes primary and secondary coils accommodated in a coil case extending to define a cylindrical mount portion on a high voltage side. The mount portion includes a high voltage terminal electrically connected with the secondary coil. A coil spring electrically connects the high voltage terminal with a sparkplug. An electrically insulative plug cap is attached to the mount portion. The coil spring has a low voltage end electrically connected with the secondary coil via the high voltage terminal. The coil spring has a high voltage end in contact with a terminal of the sparkplug. The coil spring has an intermediate portion between the low voltage end and the high voltage end. The plug cap has a spring support portion, which is partially defining the fitting hole and restricting the intermediate portion of the coil spring from being radially deformed.

Abstract: The present invention relates to an electronic sensor, particularly an inductive sensor, comprising a casing sleeve, a sensor element for measuring a physical measurand, the sensor element being placed at a measurement end of the casing sleeve, an electronic module located in the casing sleeve and a connector, which is placed on a connection end of the casing sleeve opposite to the measurement end. According to the invention, the sensor is characterized in that the casing sleeve is provided with a plastic internal lining, which is closed at the measurement end of the casing sleeve and that the internal lining extends to the casing sleeve connection end to such an extent that the connector is in a sealing engagement with the internal lining. The invention also relates to a method for the manufacture of a sensor.

Abstract: An inductive coupler provides an interface between a power line and a communication device which communicates via the power line. The power line operates at a potential between four and 140 kilovolts while accommodating a current having a frequency between 45 and 65 hertz, and the communication device operates substantially at ground potential. The inductive coupler includes a split ferrite core having material selected to provide a substantially flat frequency response between one and 50 megahertz. The coupler also includes a clamping mechanism allowing the inductive coupler to clamp around the power line or around a utility line connected to the power line. Further, the coupler includes at least one lead for communicatively connecting the inductive coupler to the communication device. The inductive coupler forms an air gap when the inductive coupler is clamped. If the coupler is insulated, the insulation is also used for the air gap.

Abstract: An electrical connection set-up for connecting thin enameled wires in ignition coils, which is to replace thermal methods, for example. This is achieved in that, to produce contacting between the winding and the respective high-voltage or low-voltage outlets, an individual contact element able to be slid over the winding by its one side and is fixed in place via its other side, the contact element having a spring-type design, a sliding surface, and at least on its one side fans out in a tulip-shape in the sliding direction, in such a way that the contact element presses against the winding in a spring-like manner in the mounted state and the insulation layer is ruptured and electrical contacting takes place.

Abstract: A high voltage split core transformer and method of assembling same is provided by which the coupling factor is improved. A split core assembly is surrounded by a secondary winding that is precisely located in a burner assembly housing. Conductive members are encased within the housing and, in conjunction with traces provided on a printed circuit board enclosing the housing cavity, define first and second primary windings about the core secondary winding. This arrangement reduces the number of turns in the secondary winding and allows the use of larger cross-sectional wire which increases the current carrying capability thereof, making the transformer suitable for D1-D5 automotive headlamp applications.

Abstract: The invention relates to a coil housing device, in particular, for a solenoid valve, comprising a coil body (2) and a rest or support element (4), integrally embodied with the coil body (2). The coil body (2) and the support element (4) have an essentially hollow cylindrical embodiment, for housing a magnet core (6), whereby the support element (4) is at least provided in the region of the magnet core (6) to be housed and the coil body (2) forms the inner surface (8) of the coil housing device, at least in the region of the magnet core (6) to be housed.

Abstract: An electronic transformer used in low voltage lamps mainly includes an outer case, an electronic controlling circuit and a voltage switch isolating transformer. Therein, the outer case consists of an upper cover plate (1) and a lower cover plate (2); the electronic controlling circuit and the magnetic core coil (6) of the voltage switch isolating transformer are put between the upper cover plate (1) and the lower cover plate (2); characterized in that the outside of the lower cover plate (2) provides concaving grooves (9) adapting to coil winding, the corresponding line passage holes (10) and a center hole (12) of the lower cover plate; the windings of the voltage switch isolating transformer are embedded in the grooves (9) through the center hole (12) of the lower cover plate, the line passage holes (10) and the center hole of the magnetic core coil (6), the upper cover (1) plate and the lower cover plate (2) are embedded with each other.

Abstract: An ignition coil includes primary and secondary coils. The primary coil includes a primary spool and a primary winding wound on the spool. The primary winding has a second winding layer wound around a first winding layer. The primary spool has first and second overhangs protruding radially outwardly from a first spool end portion of the primary spool. The first overhang is positioned away from the second overhang toward a second spool end portion. The first winding layer has a first winding end portion extending from the first winding layer through a space between the first overhangs, and being wound on the first spool end portion between the first and second overhangs. The second winding layer has a second winding end portion extending from the second winding layer between the first overhangs, and being wound on the first spool end portion between the first and second overhangs.

Abstract: An ignition coil for an internal combustion engine has a rod-shaped magnetic core, which collaborates with a cushioning element in the axial direction. The magnetic core and the cushioning element are furthermore inserted into a secondary coil shell. Moreover, the coil shell has an ignition coil housing, which is filled at least partially with an epoxy resin. In order to avoid that the epoxy resin gets into the gap between the coating and the magnetic core, the cushioning element is developed as a sealing element at the same time. At the same time, the secondary coil shell has a coating on its inner wall for the accommodation of radial stresses. The ignition coil thus designed is developed to be relatively compact, and has good thermomechanical properties.

Abstract: An inductance device has a hollow center coil around which a conducting wire is wound so that a hollow portion is formed along a center axis line of the hollow center coil, a filler which is filled into the hollow portion of the hollow center coil, and includes magnetic powder or a compound including the magnetic powder, and an accommodation case which accommodates the hollow core coil and has a bottom, wherein the filler is filled into the accommodation case.

Abstract: A twin spark ignition apparatus having two high-voltage (HV) outputs incorporates features for balancing load capacitance on each HV output. The ignition apparatus provides a first high-voltage (HV) connection configured for direct mounting on a first spark plug, and a second HV connection for coupling to a second spark plug by way of an HV cable. The HV cable adds capacitance at the second HV output, as compared to a direct mount. The secondary winding is shifted by a predetermined distance, relative to the primary winding, in direction toward the direct mount end of the ignition apparatus. The shifting reduces the internal load capacitance at the second end (top), so that when the capacitance added by the HV cable is considered, the respective load capacitances are balanced. The voltage variation between the two HV outputs is reduced.

Abstract: The invention is directed to a transformer and a method of manufacturing the same, wherein the transformer has a cylindrical disc-wound coil that includes a layer of cooling ducts disposed between first and second conductor layers. The first and second conductor layers each have a plurality of disc windings arranged in an axial direction of the disc-wound coil. Each of the disc windings includes a conductor wound into a plurality of concentric turns.

Abstract: An ignition coil includes a coil body, a connector, a coil case, a filling resin, and a vent groove. The coil body includes a primary coil, a secondary coil, and a center core. The secondary coil has a secondary spool and a secondary wire wound around the spool. The center core is provided on an inner peripheral side of the secondary spool. The connector is coupled with an end of the coil body. The connector has an aligning part adapted for centering the center core. An end of the secondary spool has a tubular shape adapted for engagement with an outer periphery of the aligning part. The vent groove is provided to facing surfaces of the aligning part and of the end of the second spool. The vent groove is adapted for releasing gas around the center core to an exterior of the secondary spool.

Abstract: An ignition coil includes a coil portion that has a primary coil, a secondary coil, and an outer core. The outer core is arranged on a radially outer side of both the primary coil and the secondary coil. A fitting member, which is in a substantially cylindrical shape, has an inner periphery via which the fitting member is fitted to the outer core. A connector case has a fit hole via which the connector case is fitted to an outer periphery of the fitting member. The connector case connects with an axial end of the coil portion via the fitting member. The fitting member includes an embedded member that is at least partially embedded in the fitting member. The embedded member is formed of a material that is different in Young's modulus from a material constructing the fitting member.

Abstract: A transformer terminal is configured as a single part that includes: a base portion; a first connecting portion that is formed at a first end of the base portion and to which a winding finish end portion of a secondary wire can be connected; and a second connecting portion that is formed at a second end of the base portion and to which a high-voltage terminal can be connected. The base portion is mounted to a first flange portion of a secondary bobbin so as to be pivotable around an axis of the base portion such that the second connecting portion can adopt a withdrawn position that is shifted axially away from radially outside a secondary wire winding region of the secondary bobbin and a connecting position that aligns with the high-voltage terminal that is radially outside the secondary wire winding region.

Abstract: A twin spark ignition apparatus having two high-voltage (HV) outputs incorporates features for balancing load capacitance on each HV output. The ignition apparatus provides a first high-voltage (HV) connection configured for direct mounting on a first spark plug, and a second HV connection for coupling to a second spark plug by way of an HV cable. The HV cable would adds capacitance at the second HV output, as compared to a direct mount. Various structures are included to offset and balance the additional capacitance attributable to the HV cable so that the capacitance of the first HV connection and the second HV connection are balanced within a range. The voltage variation between the two HV outputs is reduced.

Abstract: The present invention relates to an ignition coil for ignition systems, in particular a rod ignition coil for internal-combustion engines, comprising at least one primary winding and at least one secondary winding, a high voltage being induced in the secondary winding when current flows in the primary winding. A ferromagnetic core is surrounded in part by the primary winding and the secondary winding and one of the two windings is additionally surrounded at least in part by the other. To provide an improved ignition coil which ensures increased reliability in operation and energy efficiency and a reduced risk of overheating during operation, at least one of the windings comprises at least one portion having an elevated winding density relative to the remaining winding density, the diameter of the innermost turns in the at least one portion being smaller than the diameter of the innermost turns in the remaining winding portions.

Abstract: An encapsulatable package for a magnetic device that includes a magnetic core. In one embodiment, the encapsulatable package for the magnetic device also includes a shielding structure located about the magnetic core configured to create a chamber thereabout. The shielding structure is configured to limit an encapsulant entering the chamber.

Abstract: A distributorless ignition coil has two high voltage secondary windings wound around a primary winding, with each secondary winding being electrically connected to a respective spark plug. A shield surrounds the secondary windings. The secondary windings share a common center tap between them, and the center tap is electrically connected to the shield, which thus acts as a conductor to convey current back to an end of the shield that conveniently may be connected to ignition components to complete the electrical path, thus obviating the need for an interior wire extending from the center tap inside the coil to the end of the coil case.

Abstract: A power module located on a substrate. In one embodiment, the power module includes power conversion circuitry with a magnetic device and at least one switch. The magnetic device includes a magnetic core with a shielding structure located about the magnetic core configured to create a chamber thereabout. The power module also includes an encapsulant about the power conversion circuitry. The shielding structure is configured to limit the encapsulant entering the chamber thereby allowing the encapsulant to surround a portion of the magnetic core within the chamber.

Abstract: An ignition coil includes a cylindrical portion capable of being inserted into a plughole of an engine case. The cylindrical portion has a base end and a tip end, respectively, in an axial direction of the cylindrical portion. The cylindrical portion has an elastically deformable outer peripheral portion that engages with the plughole to fix an outer periphery of the cylindrical portion with respect thereto.

Abstract: A high voltage switching apparatus delivers kV pulses to a load such as a magnetron. The switching apparatus comprises a switching stack surrounded by capacitors and both arranged within a housing. Lt power is supplied to the stack, e.g. for control electronics, by magnetic coupling across a non-conducting wall of the housing. Annular inserts are arranged on either side of the wall. Each insert receives a transformer core and winding. The bottom surfaces of the inserts carry a conductive coating to minimise electric stresses. Ht power is also supplied through the wall.