Abstract: An external inductor for magnetic pulse welding and forming includes an outer steel frame and an inner beryllium-bronze alloy insert which is removably mounted within the frame. The steel frame and the beryllium bronze insert respectively split the responsibility for higher mechanical strength and more concentrated pulse current on the inner surface of inductor's central opening. The improved external inductor design is capable of creating greater impulse forces onto the outer workpiece and has been demonstrated to perform at least 25-30% more deformation than a simple one piece simple steel external inductor for a full metallurgical joint.

Abstract: An elastic molded insulating member such as rubber and elastomers is mounted at the end of an electrostatic shield ring attached to the end of a winding, or an electrostatic shield ring is made of an elastic material. The electrostatic shield is in tight contact with the winding, reliably improving the dielectric strength.

Abstract: A free-wound electromagnetic yoke is formed by winding the X-axis with a continuous piece of heat bondable wire wound around a plurality of coil forms positioned on a mandrel and turned by a lathe. After winding, the mandrel is heated to cause the windings to form solid coils. After cooling, the solid coils are removed from the mandrel and from the coil forms. The same process is repeated for the Y-axis. The solid coils for both the X-axis and the Y-axis are placed in a toroidal support ring to form an electromagnetic yoke.

Abstract: A noncontacting power transfer apparatus, a noncontacting signal transfer apparatus(to be referred to below as a power coupler and a signal coupler, respectively), and a separate machine apparatus that uses these couplers are disclosed. The power coupler is composed of a primary side and a secondary side that are fixed to a static unit and rotatable unit of the machine apparatus, respectively, such that its output does not vary with arbitrary rotation by the rotatable unit. The signal coupler is composed of receiving side portion having a electric-to-light conversion device that converts an electric signal to an optical signal of rotational symmetry relative to the axis of rotation of the rotatable unit and a photoelectric conversion device that converts an optical signal to an electric signal. Accordingly, the rotatable unit can be supplied with power from the static unit even while rotating, and moreover, can communicate with the static unit.

Abstract: A current transformer for monitoring a current in a conductor. The current transformer comprises a winding assembly that includes a resistive load. The transformer further comprises a compensation circuit that has an impedance selected to reduce output signal overshoot across the output terminals of the current transformer caused by the intrinsic inductance of the resistive load. The transformer also comprises a small gauge semi-rigid coaxial cable to reduce a loop pickup area formed by the conductive paths that connect the winding assembly terminals of the winding assembly and the output terminals of the current transformer. This results in output signal overshoot across the output terminals being further reduced. Additionally, the transformer comprises a transformer shield that encloses the winding assembly and has end portions that do not contact each other to define a gap that prevents the transformer shield from acting as a shorted turn.

Abstract: The stator winding of an electrical machine comprises conductor elements which are spaced apart from one another, are electrically insulated from one another and are surrounded over their entire length by common main insulation. The cavities, which are caused by the arrangement on both bar narrow sides of the conductor elements and the main insulation, are filled with an electrically semiconductive compound which, for its part, is covered by an electrically semiconductive strip. In order to provide a smooth bar surface, the electrically semiconductive strip is composed of a fiber-reinforced plastic, which has incisions on alternate sides of the narrow sides of the conductor bar oriented transversely with respect to the bar's longitudinal direction; these incisions are deeper than half the strip width and have a cut width which is on the order of magnitude of the strip thickness.

Abstract: A pulse transformer for use in a high frequency motor controller to isolate the electronic control stages from the power stages in a motor controller. The primary and secondary windings are wound on a common ferrite core and spaced apart from one another. The wire size used for the windings is relatively small (gauge 37 or less). Each of the windings has between 10 and 13 turns. The interwinding capacitance must be below 5 picofarads, preferably below 1 picofarad, and most preferably below 0.2 picofarads.

Abstract: A transformer in which a magnetic medium provides flux paths within the medium, two or more windings enclose the flux paths at separated locations along the paths, and an electrically conductive medium, arranged in the vicinity of the magnetic medium and the windings, defines a boundary within which flux emanation from the magnetic medium and the windings is confined and suppressed. In a transformer constructed in accordance with the present invention, both controlled values of leakage inductance and the benefits of separated windings can be achieved. The conductive medium can be configured to reduce the leakage inductance of a controlled-leakage inductance transformer (e.g. for use in a zero-current switching power converter), having separately located windings, by at least 25%, and can be configured to reduce the leakage inductance of a low-leakage inductance transformer (e.g. for use in a PWM power converter), having separately located windings, by at least 75%.

Abstract: A highly accurate electromagnetic-induction-type conductivity and dielectric constant meter is obtained by using a calibration box (instrument) and a structure as below. The conductivity and dielectric constant meter employs an electromagnetic inductive probe which includes a primary transformer composed of a toroidal core with a wound primary coil, a secondary transformer composed of a toroidal core with a wound secondary coil, an electrostatic shield shielding the transformers, and cables that connect the probe to a meter. To eliminate the electrostatic capacity produced by causes other than electromagnetic induction, the structure of the probe is symmetrical. In a first embodiment, the secondary transformer is placed between two parts of the primary transformer, which has two cores of the same shape that are placed symmetrically.

Abstract: A resin-rich electrically conductive felt material is described. The described conductive felt can be used to suppress corona discharge in high voltage generator coils. The conductive felt is prepared by treatment with electrically conducting polymers, such as polyaniline and polypyrrole, and resistivity values ranging from 4,000 to 100,000 ohms may be obtained. This treated felt can be readily impregnated with thermoset resins, such as epoxies, to provide flexible prepregs suitable for coil bonding applications in turbine generators.

Abstract: A rotary transformer includes a rotor core formed by stacking channel parts to form a required number of channels. Each channel part is formed by stacking two kinds of annular magnetic rings so that two rings having the same outside and inside diameters are placed at both sides of a ring having the same inside diameter as the two rings but a greater outside diameter than the two rings. A stator core is also formed by stacking channel parts to form the required number of channels. The channel part is formed by stacking two kinds of annular magnetic rings so that two rings having the same outside and inside diameters are placed on both sides of a ring having the same inside diameter with the two rings but smaller outside diameter than the two rings. A thin layer of glass can be used to bond the rings of the stator or rotor together.

Abstract: A metal detector comprise a coiled conductor located within a metal enclosure operative to provide an a.c. generated primary electromagnetic field. Metal screening is provided adjacent the coil so as to provide a secondary induced magnetic field which opposes the primary electromagnetic field so as to significantly reduce the metal free zone.

Abstract: A transformer in which a magnetic medium provides flux paths within the medium, two or more windings enclose the flux paths at separated locations along the paths, and an electrically conductive medium, arranged in the vicinity of the magnetic medium and the windings, defines a boundary within which flux emanation from the magnetic medium and the windings is confined and suppressed. In a transformer constructed in accordance with the present invention, both controlled values of leakage inductance and the benefits of separated windings can be achieved. The conductive medium can be configured to reduce the leakage inductance of a controlled-leakage inductance transformer (e.g. for use in a zero-current switching power converter), having separately located windings, by at least 25%, and can be configured to reduce the leakage inductance of a low-leakage inductance transformer (e.g. for use in a PWM power converter), having separately located windings, by at least 75%.

Abstract: A transformer comprising a core, a plurality of primary coils and a plurality of secondary coils, the core having three sections arranged in a generally triangular configuration forming three vertices, the coils being disposed on the core about respective vertices, each of the core sections having at least one mitered side abutting a mitered side of an adjacent core section.

Abstract: The present invention contemplates a significant departure from known shielded enclosure designs by providing an enclosure for electronic modules, comprising walls made of composite material including conductive fibers for shielding the enclosure interior from electromagnetic radiation, and means for securely mounting at least one module inside the enclosure with a fastener means, the mounting means comprising composite material. The present invention further contemplates methods for making shielded enclosures and card guides for such enclosures that represent a significant improvement over known enclosure designs. This invention contemplates composite cold walls and composite fins. These composite fins and cold walls may be used alone or together in structures and enclosures which are useful in conducting heat.

Abstract: A printed coil, having good magnetic coupling, low loss, and good high frequency characteristics, comprises a plurality of conductor forming planes on which a conductor pattern having one or more turns are formed centered about a core inserting hole and which are laminated together with an insulating layer, each of the conductor forming planes being provided with outer peripheral connecting holes provided on an outer periphery of the conductor pattern, and a plurality of inner peripheral connecting holes provided on an inner periphery thereof, with the outer and inner peripheral connecting holes being connected to the conductor pattern; a connecting coil which is laminated together with the conductor forming planes and having a connection pattern thereon for connecting the outer and inner peripheral connecting holes, and circuitry for electrically connecting the outer and inner peripheral connecting holes and the connecting coil.

Abstract: A high-tension current transformer having two or three type of insulating units with one coil, the transformer being provided for storing and for being assembled in a short time, to prevent the need for performing the insulation and the production of transformers on order.

Abstract: A shielding sleeve (19) for SQUID-magnetometers which serves to shield from electromagnetic interference fields, consists of an electrically conductive shielding material so as to obtain adequate RF shielding in conjunction with a low noise contribution, completely envelops a non-shielding cryostat (10), has a predetermined sheet resistance and consists of at least one layer of the shielding material in order to avoid an increase of the magnetometer overall noise.

Abstract: A multilayer printed circuit board (100) includes a plurality of layers (101, 102, 104, 106, 108 and 110). Located within intermediate layer (106) is an inductor (200) which is shielded by top layer ground plane (202) and bottom layer ground plane (204). In another embodiment of the present invention, the inductor (200) can have its inductance adjusted by way of a inductance adjustment runner (316, 318) or by an electronic inductance adjustment device (408).

Abstract: A magnetically variable inductor for high power, high frequency applications which includes a solenoid with a magnetic core therein, disposed coaxially around a conductor for carrying the high power, high frequency signal and a variable current source coupled with the solenoid so that a manipulation of the current through the solenoid results in a variable inductance for said conductor. Also disclosed are additional features of ferrite rings disposed around each end of the magnetic core, a shield disposed between the core and the solenoid, and a sheath disposed around the solenoid.

Abstract: The disclosure discusses impedance matching circuits based on parallel-resonant L-C tank circuits, and describes a low-loss design for an adjustable inductance element suitable for use in these parallel tank circuits. The application of an impedance matching circuit to a plasma process is also disclosed; in this context, a local impedance transformation circuit is used to improve power transfer to the plasma source antenna.

Abstract: A method for making a search coil frame assembly for a metal detector, the method comprising providing a plurality of frame members, each having an aperture therethrough, providing selected ones of the frame members, respectively, with first, second and third grooves in face surfaces thereof, the grooves being formed so as to extend substantially around the apertures and to an edge of the frame member, placing electrically conductive strands in the grooves, and bonding the frame members together to close the grooves with the strands therein, the grooves being disposed such that the first and third grooves are spaced from the second groove by substantially equal distances on opposite sides of the second groove, the apertures forming a passage through the bonded frame members, and the strands substantially encircling the passage and extending from the frame.

Abstract: Disclosed is a rotary transformer transmitting signals without any physical contact between its rotary part and its stationary part. In the rotary transformer, cores having different frequency characteristics are integrally combined so that signals having a plurality of different frequency ranges can be selectively transmitted by cores having frequency characteristics optimum for such frequency ranges, thereby improving the signal transmission efficiency and reducing the size of the rotary transformer system.

Abstract: A length of wire is toroidally wound, and then the toroid is encapsulated and cut in two along a plane that is perpendicular to the toroidal axis. The resulting portions are used as stator and/or armature of a solenoid, and in the solenoid the cut face of each forms one side of the solenoid's working gap so that the faces move toward and away from each other as the solenoid operates.

Abstract: A method for making a search coil frame assembly for a metal detector, the method comprising providing a plurality of frame members, each having an aperture therethrough, providing selected ones of the frame members, respectively, with first, second and third grooves in face surfaces thereof, the grooves being formed so as to extend substantially around the apertures and to an edge of the frame member, placing electrically conductive strands in the grooves, and bonding the frame members together to close the grooves with the strands therein, the grooves being disposed such that the first and third grooves are spaced from the second groove by substantially equal distances on opposite sides of the second groove, the apertures forming a passage through the bonded frame members, and the strands substantially encircling the passage and extending from the frame; and the search coil frame assembly made in accordance with the aforesaid method.

Abstract: The current and voltage transformer (10, 11) is intended for a metal-encapsulated, gas-insulated high-voltage installation. It has an annular supporting body (13) which can be fixed inside the metal encapsulation (7) and is used for holding a current sensor and a voltage sensor. The current sensor, held on the supporting body (13), is constructed as a toroidally wound coil (14) and the voltage sensor, held on the supporting body (13), is constructed as a hollow-cylindrical measurement electrode (15). After fitment in the installation, the coil (14) and measurement electrode (15) concentrically surround a current conductor (5) of the installation. This current and voltage transformer is intended to have small dimensions and is intended to be capable of fitment without problems at any point in the installation.

Abstract: A motor control system includes a single, multicompartment enclosure mounted on a skid. The enclosure contains a transformer circuit and a motor controller circuit interconnected so that only external connections to a power source and a load are needed. When the circuits are energized, access to high voltage motor control components and to field replaceable fuses and output selection switches is prevented by a double interlocking mechanism which operates in conjunction with energizing and deenergizing the transformer. The transformer of the transformer circuit includes a tertiary winding disposed radially between a primary winding and a secondary winding. The winding filters electrostatically coupled transients. A conventional electrostatic shield is also used so that the transformer is doubly shielded to electrostatic transients. The tertiary winding is connected to one or more capacitors to filter magnetically coupled transients.

Abstract: An inductive device comprises a first winding which is provided on a core and which is composed of electrically conductive segments which are shaped approximately as a U-shaped plate having two substantially parallel end portions of unequal width and a wedge-shaped central portion. The segments are formed as metallized portions of the outer surface of a cap which is made of an electrically insulating material and which is shaped as a ring having a U-shaped cross-section. The segments are electrically isolated from one another by non-metallized strip-shaped portions of the outer surface of the cap. The cap comprises includes metallized pins which constitute connection members for the segments and which are connected to electrical conductors, for example, on a printed circuit board. In conjunction with the segments, the conductors constitute the first winding.

Abstract: In a non-contact IC card based on an electromagnetic induction system, N small thin-film coils formed by thin-film technology are arranged to perform N-bit parallel data transfer at an increased data transfer rate. Each thin-film coil may be constructed with a pot core to solve a problem relating to errors in positioning the card relative to a terminal unit and thereby improving the reliability of data transfer. Shielding walls may be provided between the adjacent thin-film coils to prevent interference therebetween. The N thin-film coils are integrally formed as a thin-film coil module.

Abstract: A line filter arranged in such a manner that a foil conductors are used as the coil conductor and the shield plate, and a reactor is formed therein by laminating and winding the foil conductor and the shield plate with an insulating material held therebetween. A line filter arranged in such a manner that a pair of coil blocks connected to each other in parallel is provided on the iron core leg is included in the scope of the invention. Each of the coil blocks is structured in such a manner that the coil conductor and the shield plate made of the foil conductors are stacked and wound via the insulating material. A structure is included within the scope of the invention, the structure having a plurality of filter mechanisms connected to one another in series, each of the filter mechanisms being constituted by a pair of coil blocks connected to each other in parallel.

Abstract: Turns of primary and secondary windings of a chopper power supply transformer are formed by magnetically coupled stacked parallel planar printed circuit conducting layers. The primary winding is between first and second parts of the secondary winding that are connected in series and parallel. Layers at opposite ends of the primary winding are (i) arranged to reduce leakage currents between the secondary winding parts and (ii) positioned between further layers of the primary winding and the secondary winding. Terminals of the first and second layers are connected together as a first input terminal of the transformer. Other terminals of the first and second layers have a common connection. Further layers of the primary winding are connected in series with each other between the common connection and a second input terminal of the transformer.

Abstract: A noise-shielded transformer is constructed with a toroidal core having mounted thereon a secondary winding, a bifilar shield winding, a conductive plate, an insulating member, a high voltage winding, and a primary winding. The secondary winding is located inside the other windings, making the assembly work easier and increasing the noise shielding effect. Multiple shielding, by the bifilar shield winding and the conductive plate, increases the capacitance between the secondary winding and ground and decreases the capacitance between the primary winding and the secondary winding, so that the noise eliminating characteristic with respect to pulse-property noise and high frequency-property noise is enhanced substantially. It is also possible to obtain a grounding effect and a noise-bypass effect by connecting a resonance condenser from ground to one end of the bifilar shield winding.

Abstract: A high frequency power transformer having a multi-element magnetic shield conforming to the surface of the structure including provisions for specific features of the magnetic circuit and winding assembly. The winding is disposed on one side of a four-sided magnetic circuit and is partially surrounded by a close fitting electrically continuous loop. The winding assembly includes an area having a higher electrostatic field and is surrounded by a second electrically continuous loop which is spaced apart from the winding assembly, providing significant electrostatic shielding and air movement over the winding assembly while avoiding arcing between the shield and the winding assembly due to the high electrostatic field.

Abstract: A noise-shielded transformer which suppresses electrical noises by absorbing conductible electrical noises that flow into the power line to cause interference, consisting of a gapless-type toroidal core, a primary winding and a secondary winding uniformly wound after dividing the entire magnetic path of the toroidal core in two, and conductive plates mounted to wrap the primary winding and secondary winding, respectively, wherein conductive plates are mounted in the gap of the toroidal core to magnetically isolate the primary winding and the secondary winding, conductive plates are mounted outside the gap of the toroidal core and the gapless-type toroidal core has a configuration of continuously winding steel shield of directional silicon.

Abstract: A search coil assembly for an inductive search device is described having a hield formed from a carrier layer and a thin metal coating applied thereupon, in which the coating is arranged into a plurality of parallel circuit tracks. The circuit tracks are electrically connected to one another by connecting tracks and to a reference potential. The described search coil assembly can be advantageously constructed by multi-layer circuit board technology.

Abstract: A metal detector search coil assembly comprising a frame assembly having an aperture therethrough, electrically conductive strands wound upon the frame assembly, potting plastic disposed on external surfaces of the frame assembly embedding the strands, and a metal housing enclosing the potting plastic, the frame comprising a plurality of frame members joined together to form the aperture, each of the frame members comprising first and second sheets of rigid plastic bonded together with an electrically conductive material disposed therebetween, and adhesive being disposed on the sheets to bond the sheets together; and a method for making such a metal detector search coil assembly.

Abstract: A semi-conducting pyrolyzed glass fiber layer equalizes the electrical potential on the exterior surface of an insulated conductor when the layer covers the surface. The layer prohibits the development of a corona discharge and bleeds off any electrical charge developed thereon when the layer is electrically coupled to a body having a known potential. The insulated conductor may be windings in a dynamoelectric machine.

Abstract: A stationary induction apparatus for supplying and receiving high frequency power of several tens KHz, wherein a partition wall made of a non-magnetic metallic foil in a thickness less than 1/10 the depth of penetration in the using freqency for electromagnetic induction is provided so as to separate the supply side (primary side) from the receiver side (secondary side), so that the stationary induction apparatus is not hurt in its function as an induction apparatus, but can electromagnetically shield the primary side from the secondary side, and the secondary side of the boosting transformer of the magnetron is able to be placed within the shield casing, thus realizing a light, compact and inexpensive microwave generating device for use in an electronic oven.

Abstract: A high-frequency heating apparatus comprises a power supply including a commercial power supply or a battery, a frequency converter for converting the power of the power supply into high-frequency power, a boosting transformer for increasing the voltage of the output of the frequency converter, and a magnetron for receiving the output from the boosting transformer. The apparatus further comprises a shield member made of a non-magnetic conductive material and forming a substantially electrical open loop in the winding direction of the primary winding between the primary and secondary windings of the boosting transformer. The shield member is connected to the core or the housing of the boosting transformer thereby substantially containing a high-voltage circuit in the shield space. High safety of the high-frequency heating apparatus is thus assured without grounding the housing.

Abstract: A light-weight, integrated enclosure and fully-adjustable mounting and support system for transport and use of mobile electronic equipment in the field. A curved upper shell and flat base of sandwich panel construction are connected by reinforced plastic members to form a lightweight enclosure which can be mounted on a truck for transport. The fully adjustable mounting and support system includes rails mounted within the enclosure on which a series of frame elements are horizontally movable to accomodate electronic equipment of varying widths between the frame elements. The frame elements are also lightweight extrusions and include an elastomeric pad engaged in a vertical channel to provide infinite vertical adjustability in mounting the equipment to the frames. The enclosure is shaped for efficiently housing the equipment, reducing aerodynamic drag, and providing superior structural strength and stiffness.

Abstract: A multiconductor shielded connector is disclosed in which a flexible, compressible double bushing is used between the connector half shells and the multiconductor cable. The double bushing comprises an outer bushing dimensioned to grasp the outer jacket of the cable at the exiting end of the connector. A concentric, longitudinally offset inner bushing is inserted under the shielding (braid or foil) and mates with ridges on the inner surface of the half shells to form a tight, continuous radiation seal. A ferrite ring is inserted into a recess on the inner diameter of the inner bushing to provide noise suppression for signals traveling through the conductors of the cable. The inner and outer bushings are connected together with a fine web which maintains concentricity and axial displacement of the bushings before and during assembly, but which does not interfere with the operation of the connector after assembly.

Abstract: A method for making a coil assembly for a metal detector of the type used for detecting metal fragments in foodstuffs and pharmaceuticals, the method comprising providing a frame of non-metallic material, the frame having an aperture therethrough for the passage of material undergoing inspection, winding coils of electrically conductive strands on the frame, applying a first plastic coating in liquid form to the frame and coils, less the aperture portion of the frame, applying metal in fluid form to the first plastic coating to encase the first plastic coating in a metal layer, and applying a second plastic coating in liquid form to the metal layer to encase the metal layer in a second plastic coating.

Abstract: A combined current and voltage measuring sensor for measuring voltage and current on a primary conductor, the sensor including a cast resin body having therein a aluminum support, the support having an aluminum encasement mounted thereto. An open air coil is located in the encasement adjacent a grooved portion in the cast resin body for maintaining the primary conductor in the top of the cast resin body. The groove and the aluminum encasement cooperate to precisely located the primary conductor with respect to the open air coil. A keeper assembly mechanically maintains and locates the primary conductor in the groove and further provides an electrical connection from the primary conductor to the voltage measuring apparatus of the sensor.

Abstract: A current detector for detecting the high frequency current flowing in a conductor includes a coil of high resistivity material wound around an non-ferromagnetic core. The coil is arranged in a substantially closed loop configuration around the conductor carrying the current to be measured. The ratio of the winding spacing to the cross sectional area of the coil is maintained constant over the length of the winding. A shield of high resistivity material surrounds the coil and is spaced from the coils and the shield has a gap oriented along an azimuth of the closed loop winding and directed orthogonal to the net current direction of the current induced in the coil. The ends of the coil are coupled to a high impedance voltage detector through high resistivity leads and a relatively low value resistor is coupled between the leads to reduce the quality factor.

Abstract: A method for making a coil assembly for a metal detector of the type used for detecting metal fragments in foodstuffs and pharmaceuticals, the method comprising providing a frame of non-metallic material, the frame having an aperture therethrough for the passage of material undergoing inspection, winding coils of electrically conductive strands on the frame, applying a first plastic coating in liquid form to the frame and coils, less the aperture portion of the frame, applying metal in fluid form to the first plastic coating to encase the first plastic coating in a metal layer, and applying a second plastic coating in liquid form to the metal layer to encase the metal layer in a second plastic coating.

Abstract: A coil assembly for a metal detector of the type used for detecting metal fragments in foodstuffs and pharmaceuticals, the coil assembly comprising a frame of non-metallic material, the frame having an aperture therethrough for the passage of material undergoing inspection, coils of electrically conductive strands wound upon the frame, a first plastic coating adhered to the frame and coils, less the aperture portion of the frame, a layer of metal adhered to the first plastic coating to encase the first plastic coating in the metal layer, and a second plastic coating adhered to the metal layer to encase the layer in the second plastic coating.

Abstract: A current detector for detecting the high frequency current flowing in a conductor includes a coil of high resistivity material wound around an non-ferromagnetic core. The coil is arranged in a substantially closed loop configuration around the conductor carrying the current to be measured. The ratio of the winding spacing to the cross sectional area of the coil is maintained constant over the length of the winding. A shield of high resistivity material surrounds the coil and is spaced from the coils and the shield has a gap oriented along an azimuth of the closed loop winding and directed orthogonal to the net current direction of the current induced in the coil. The ends of the coil are coupled to a high impedance voltage detector through high resistivity leads and a relatively low value resistor is coupled between the leads to reduce the quality factor.

Abstract: A coil assembly for a metal detector of the type used for detecting metal fragments in foodstuffs and pharmaceuticals, the coil assembly comprising a frame of non-metallic, the frame having an aperture therethrough for the passage of material undergoing inspection, coils of electrically conductive strands wound upon the frame, plastic material adhered to the frame and coils, less the aperture portion of the frame, and a coating of metal adhered to the plastic material to encase the plastic material in a metal layer.

Abstract: A microwave oven comprises a cooling system and a magnetic shield system applied to a plurality of circuit elements. The cooling system comprises a compartment through which air can pass. The compartment is formed by at least one printed circuit board carrying a plurality of circuit elements and a supporting member for supporting the printed circuit board. The circuit elements are cooled by the flow of the air. In addition, the circuit elements are magnetically shielded from a magnetic field generation device such as a magnetic card reader/writer and a high voltage transformer by a shield member. It is possible that the circuit elements are protected from very large quantities of heat emitted by the high voltage transformer. The magnetic card reader/writer may be provided for reading/cooking program information from a magnetic card and writing the same on it. The microwave oven should be controlled according to the cooking program information for cooking purposes.

Abstract: A transformer includes first and second coils which are generally cylindrical and having an outer circumferential surface, an inner diametral surface and first and second axial extremities. Shielding is disposed around the coils comprising a web shaped metallic, non-magnetic, electrically conductive generally rectangular first member. The first member has a first portion extending about substantially the entire inner diametral surface of the coils and has a plurality of tab shaped portions extending respectively about a substantial portion of each of said first and second axial extremities. A second non-magnetic, electrically conductive metallic member extending over substantially the entire circumferential extent of each coil.