Abstract: A manufacturing method of a magnetic element includes the following steps: forming a block including a central post and at least one lateral post with magneto-conductive materials; cutting the block along a first plane passing through the central and lateral posts to form a first half body and a second half body; combining the first half body with the second half body to form a first air gap between the central post of the first half body and the central post of the second half body and a second air gap between the lateral post of the first half body and the lateral post of the second half body; and cutting or grinding the combined first half body and second half body along a second plane passing through the central post and the lateral post to form a third half body including the first and second air gaps.

Abstract: A thermomagnetic power generator is provided. The thermomagnetic power generator includes: at least one set of magnetic poles; at least a trough, filled with a fluid; and a plurality of chain links, linked into a closed chain, wherein each of the chain links is made of the magnetic material and a first part of the closed chain is inside the trough and immersed by the fluid while a second part of the closed chain is outside the trough and exposed to an environment. The fluid and the environment are at different temperatures, wherein the set of magnetic poles causes different forces on the first and the second part of the closed chain due to the thermomagnetic effect so as to generate a torque upon the closed chain to drive the closed chain.

Abstract: An arrangement of a NTC resistor in an electromagnet includes an electromagnetic coil comprising a main winding and a shunt winding, a coil carrier configured to have the electromagnetic coil be wound thereon, a first contact terminal and a second contact terminal configured to supply a voltage, a NTC resistor, a first contact lead comprising a first contact lead end, a second contact lead comprising a second contact lead end, and a third contact lead. The first contact lead, the second contact lead and the third contact lead are configured to interconnect the first contact terminal, the second contact terminal, the main winding, the shunt winding, and the NTC resistor. A fixing element is configured to be elastically deformable and to exert a spring force so as to fix the NTC resistor between the first contact lead end and the second contact lead end.

Abstract: A device for controlling a magnetic flux in an electromagnetic system, wherein the system includes magnetically connected magnetic cores, between which a volume is arranged. The volume includes a controllable magnetic flux region and the magnetic flux region includes a magnetic material having a relative permeability that may be varied by influencing the temperature of the material. The magnetic material includes a magnetic material, the Curie point of which lies within the temperature operating range of the device and exhibits paramagnetic properties within the temperature range. Also a method of controlling a magnetic flux.

Abstract: A method of manufacturing a solenoidal magnet structure, includes the step of providing a collapsible accurate mold in which to wind the coils winding wire into defined positions in the mold, placing a mechanical support structure over the coils so wound, impregnating the coils and the mechanical support structure with a thermosetting resin, allowing the thermosetting resin to harden, and collapsing the mold and removing the resultant solenoidal magnet structure formed by the resin impregnated coils and the mechanical support structure from the mold as a single solid piece.

Abstract: A cryostat (1) with a magnet coil system including superconductors for the production of a magnet field B0 in a measuring volume (3) within a room temperature bore (2) of the cryostat has a plurality of radially nested solenoid-shaped coil sections (4, 5, 6) which surround the room temperature bore and which are electrically connected in series, at least one of which being an LTS section (5, 6) with a conventional low temperature superconductor (LTS) and at least one of which being an HTS section (4) including a high temperature superconductor (HTS), wherein the LTS section (5, 6) is located in a helium tank (9) of the cryostat (1) along with liquid helium at a helium temperature TL. The apparatus is characterized in that the HTS section (4) is disposed radially within the LTS section (5, 6) in a vacuum portion of the cryostat and is separated from the LTS section (5, 6) by the helium tank (9) wall (9a) facing the room temperature bore.

Abstract: One embodiment disclosed herein is an apparatus for performing a thermodynamic cycle comprising: a sample that exhibits temporary magnetic remanence; and a magnetisation apparatus for magnetising the sample, wherein the magnetisation apparatus is operable, during a first part of the thermodynamic cycle, to produce a cyclically-varying magnetising field comprising a wavetrain of a single or plurality of consecutive cycles, and to remove the magnetising field from the sample during a second part of the thermodynamic cycle, wherein demagnetisation of the sample during the second part of the thermodynamic cycle causes the generation of an independent magnetic flux.

Abstract: There is disclosed a permanent current switch which has a high temperature margin and which is thermally stable and which securely performs a switching operation between a superconducting state and a normal conducting state. The permanent current switch of the present invention has a coiled superconducting wire and a heater wire which switches the superconducting wire between the superconducting state and the normal conducting state, the superconducting wire is a magnesium diboride superconducting wire having a high-resistance metal on an outer side and a magnesium diboride superconducting portion on an inner side and prepared by forming a superconducting metal on a layer between the high-resistance metal and the magnesium diboride superconducting portion, and the permanent current switch further comprises a superconductive connecting section superconductively connected to a lead wire guided from the superconducting wire and a superconducting wire for a wiring line.

Abstract: An improved field emission system and method is provided that involves field emission structures having electric or magnetic field sources. The magnitudes, polarities, and positions of the magnetic or electric field sources are configured to have desirable correlation properties, which may be in accordance with a code. The correlation properties correspond to a desired spatial force function where spatial forces between field emission structures correspond to relative alignment, separation distance, and the spatial force function.

Abstract: A magnet arrangement with a magnet coil system (M) with two coil systems (C, D) that are each arranged in a container (B1, B2) positioned around the z axis and that are axially mechanically separated by a split (G), wherein each coil system (C, D) comprises a first (C1, D1) and a second coil section system (C2, D2), wherein the first coil section systems (C1, D1) are exposed to attractive magnetic forces showing toward the split (G) (KC2, KD2) and the second coil section systems (C2, D2), to repulsive magnetic forces showing away from the split (G) (KC2, KD2), and containing in the split (G) at least one mechanical structure that withstands compressive loads (E1, E2) and that supports a part of the attractive magnetic forces (KC1, KD1), is characterized in that, in the split (G) within the dimensions of the containers (B1, B2), a mechanical structure (H1) is provided that mechanically withstands tensile loads in the z direction, supports a part of the repulsive magnetic forces in the axial direction (KC2, KD2

Abstract: The invention concerns a pressure control valve for the control of the value of pressure in a hydraulic circuit, especially in a hydraulic circuit of a vehicle transmission, with a valve housing, with a solenoid coil, with an armature component group comprising an armature rod, an armature and advantageously, a spring, with a yoke and with a push rod, which is interposed between the armature rod and a control element, whereby the section of the valve housing (3) in the zone of the control element (16) consists of a plastic flange (2a), and further, the armature rod (1) possesses a control boring in the longitudinal direction, in which a pin (12, 12?, 12?) is inserted, the material and dimensioning are so selected, that the pin can compensate for a temperature based longitudinal change of the plastic flange (2a).

Abstract: An undulator includes a periodic arrangement of magnets to produce a periodic spatial magnetic field distribution in a magnetic gap defined by the magnets. The undulator further includes a temperature-compensating material selectively arranged to compensate for a temperature-dependent change in the magnetic field of the undulator. The change may be in the strength of the magnetic field, or in the position of the magnetic field centerline. According to one aspect of the invention, the temperature-compensating material is movably arranged, so as to fine tune its compensation effect after it is initially arranged. Alternatively or additionally, the amount of temperature-compensating material may be adjusted to fine tune its compensation effect after it is initially arranged.

Abstract: A device for influencing an electron beam, for example a beam deflecting device in an electron beam lithography machine, comprises a beam influencing coil (13) operable to influence an electron beam (EB) in the vicinity of the device by way of a magnetic field and a heat dissipation compensating coil (14) operable to provide a heat output so compensating for any change in heat dissipation of the device due to operation of the beam influencing coil (13)—particularly variable operation to vary the field intensity or to create and remove a field—as to reduce the amount of change, preferably to maintain the net heat dissipation at a constant value. The compensating coil (13) can be controlled, for example, by measurement (19) of the heat dissipation of the device and calculating (18) current supply (16) to the coil (13) in dependence on the measured dissipation.

Abstract: A particle-optical apparatus is proposed as well as a method for operating the same. The particle-optical apparatus provides a magnetic field for deflecting charged particles of a beam of charged particles and comprises a body of a material with a permeability number around which a current conductor at least partially engages and a temperature-adjusting unit for adjusting a temperature of the magnetic-flux-carrying body substantially to a nominal temperature. A relative variation of the permeability number relative to a width of a temperature range is to be smaller than a limit value a, wherein a is preferably smaller than 3·10?3K?1. In particular, the nominal temperature is at an extremum of a temperature dependence of the permeability number. Preferably, such a particle-optical apparatus can be employed in a microscopy or a lithography apparatus.

Abstract: An apparatus for performing a thermodynamic cycle comprising: a sample having a ferromagnetic phase transition temperature; means to magnetise the sample above the ferromagnetic phase transition temperature of the sample; and means to cool the sample to a temperature that is below the ferromagnetic phase transition temperature thereof, wherein the demagnetisation of the sample whilst the sample is below the ferromagnetic phase transition temperature thereof causes the generation of an independent magnetic flux.

Abstract: A particle-optical apparatus is proposed as well as a method for operating the same. The particle-optical apparatus provides a magnetic field for deflecting charged particles of a beam of charged particles and comprises a body of a material with a permeability number around which a current conductor at least partially engages and a temperature-adjusting unit -for adjusting a temperature of the magnetic-flux-carrying body substantially to a nominal temperature. A relative variation of the permeability number relative to a width of a temperature range is to be smaller than a limit value a, wherein a is preferably smaller than 3·10−3K−1. In particular, the nominal temperature is at an extremum of a temperature dependence of the permeability number. Preferably, such a particle-optical apparatus can be employed in a microscopy or a lithography apparatus.

Abstract: A color cathode-ray tube apparatus has a compensation mechanism for generating a magnetic field that compensates a change in a horizontal-deflection magnetic field due to a change in the temperature of horizontal-deflection coils. The compensation mechanism is formed of auxiliary coils to which a current is supplied in synchronism with horizontal deflection of electron beams, and a control element for controlling the current supplied to the auxiliary coils in accordance with a change in the temperature of the horizontal-deflection coils.

Abstract: Temperature compensation for a magnetic sector used in mass spectrometry. A high temperature dependant magnetic sector is used. This magnetic sector is compensated by a magnetic shunt that has opposite temperature characteristics to those of the magnet.

Abstract: In order to provide a magnetic field stabilization method, magnetic field generating apparatus and magnetic resonance imaging apparatus that is not affected by the temperature distribution in an installation space, in stabilizing a magnetic field of a magnetic field generating apparatus 2 having a pair of permanent magnets facing each other with a space interposed and yokes constituting a magnetic circuit for the permanent magnets, heat quantities to be applied to a plurality of positions are individually controlled (172, 174) based on the temperatures detected at a plurality of positions 154, 158 on the yoke to stabilize the respective temperatures at the plurality of positions.

Abstract: Provided are non-halogen, flame-resistant, resin materials and resin magnet materials, and also electron beam controllers comprising the resin magnet materials. The resin material comprises (A) a non-halogen resin composition, (B) a metal oxide hydrate, and (C) one or both of antimony trioxide and zinc borate. The resin magnet material comprises those components (A), (B) and C), and (D) a magnetic material. In the electron beam controller, the four-pole and 6-pole convergence magnets and the two-pole purity controller magnets are made of the resin magnet materials.

Abstract: A thermo-sensitive actuator capable of operating without the need of providing a temperature detector as a separate member. The actuator includes a stator made of a magnetic material to form a yoke. A rotor is rotatably provided in an opening provided in the stator. The actuator further includes pole pieces for magnetically connecting the stator and the rotor. A magnetic source is provided in any of the magnetic paths formed by the constituent elements. A thermo-sensitive magnetic material, which shows a change in magnetic characteristics, e.g. permeability, saturated magnetic flux density, or residual magnetic flux density, according to temperature, is provided in a part of the magnetic paths.

Abstract: A solenoid exhaust gas recirculation (EGR) valve (12) includes a first inductive coil (48) that generates a magnetic field when energized by a signal from a control unit (13). The magnetic field drives a ferromagnetic armature valve (64) open and closed--metering the flow of recovered exhaust gases from an engine exhaust manifold (14) to an engine air intake manifold (16). The exhaust gas flow rate depends upon the amount of current flowing through the first coil (48). The resistance of the first coil (48) is temperature-dependent. Therefore, to reduce changes in coil current and magnetic field strength due to temperature changes, the first coil (48) is connected in series with a thermistor (75) having a temperature coefficient of resistance that is opposite that of the first coil (48). A temperature stable resistor in the form of a second coil (72) is connected across the thermistor (75) to modify the thermistor temperature-response curve to more closely offset that of the first coil (48).

Abstract: A force motor having a cylindrical armature of ferromagnetic material is provided. An electromagnetic coil is disposed coaxially around the armature. First and second cylindrical plates are disposed on opposite ends of the armature in spaced proximity from the armature forming a respective gap having a predetermined length. A substantially tubular permanent magnet is disposed coaxially around the armature. The magnet is magnetized radially with respect to the longitudinal axis and provides a pair of oppositely directed magnetic flux paths. A current source energizes the electromagnetic coil, which produces an electromagnetic flux path directed through the gaps and the armature to cause the armature to move. Advantageously, temperature compensators are provided to differentially expand and contract, with respect to the cylindrical plates, in response to a varying temperature of the force motor.

Abstract: An electromagnet for a nuclear reactor shutdown system, which comprises upper and lower cores disposed in an axially symmetrical arrangement and capable of latching with and delatching from each other. When an ambient temperature increases, the upper and lower iron cores are delatched from each other and a control rod connected to the lower iron core falls down into a reactor core. The lower iron core is provided with a plurality of slits to form a plurality of fins therebetween. A temperature sensitive magnetic material (TSMM) is disposed in the outer circumferential lower corner portion of the lower iron core. An interface between the TSMM and an iron core material takes the form of a side surface of a cone whose central axis is coincident with the symmetry axis and whose apex angle lies in the range of 60.degree. to 120.degree..

Abstract: A pair of torquer magnets each comprising a cup-shaped yoke is provided with a disk-like permanent magnet and a pole piece. A through-hole provided through the center of the torquer magnet and a spool member made of a magnetic compensating metal is inserted into and fixed in the through-hole. The spool is shaped to have a central portion intermediate its end of a substantially smaller diameter.

Abstract: A first shell of magnetic material having a hollow cavity is magnetized and as a remanence to produce a first uniform field in the cavity. The first shell has a temperature coefficient such that the first uniform field varies with temperature in a first direction. A second shell, mounted concentrically with the first shell, has a remanence substantially the same as the remanence of the first shell and is magnetized to produce a second uniform field in the cavity in the same direction as the first uniform field. The second shell has a temperature coefficient that is opposite to and much larger than the temperature coefficient of the first shell. Changes in temperature will cause the cavity fields produced by each of the two shells to vary in opposite directions such that there will be virtually no net change in the combined cavity field.

Abstract: A color cathode-ray tube-yoke combination comprises a color cathode-ray tube having a glass envelope and a yoke for producing magnetic fields positioned thereon. At least one semi-flexible corrective magnet is attached to a curved portion of the envelope. The novel corrective magnet is improved over prior corrective magnets by the inclusion therein of at least one portion of reduced thickness which increases the flexibility of the corrective magnet to provide conformity to the curved surface portion of the envelope.

Abstract: A superconducting electromagnet for nuclear magnetic resonance imaging has a pair of Z gradient coils surrounded by a heat shield. The heat shield comprises an electrically-conducting tube having one or more cylindrical portions which have longitudinal slits formed therein and at least two annular portions which do not have slits and which are integral with the cylindrical portions. The annular portions are inductively coupled with the Z gradient coils. The axial positions of the centers of the annular portions are selected such that the sum of the cubic term in the expression for the magnetic field generated by eddy currents which are induced in the annular portions and the cubic term in the expression for the magnetic field generated by the Z gradient coils is equal to zero. The resulting composite magnetic field varies substantially linearly along the longitudinal axis of the electromagnet.

Abstract: A solenoid valve comprising: a stator; a coil responsive to current into thereto, and magnetically connected to the stator. The coil characterized such that its resistance changes with temperature to increase or decrease, as the case may be to vary the amount of flux generated. A valve seat positioned about one end of the stator defining a valve seating surface positioned at a predetermined distance for the one end and a flat armature movable relative to the valve seat and when seated thereon is spaced from the one end. The armature fabricated of a bi-metallic, thermally responsive element for causing a portion of such armature to move closer to or farther from the stator to vary the distance between such portion on the one end as a function of temperature to compensate for the changes in magnetic flux.

Abstract: To reduce the running cost of an MRI apparatus, power supplied to a normal conductive coil from a pre-regulator is reduced in an idling mode. This reduction in power also reduces the heat generated in the normal conductive coil and a shunt resistor. A computer controls a cooling unit according to the amount of the heat reduced in order to reduce to flow rate of a cooling medium. In this manner, the temperatures of the normal conductive coil and shunt resistor can be maintained at constant levels. Further, if a current value is set to maintain the temperatures of the normal conductive coil and shunt resistor at the constant levels only by natural heat radiating, circulation of the cooling medium can be stopped.

Abstract: A deflection device generating magnetic field for electron beam deflection comprises, a cylindrical mold, a horizontal deflection coil provided inside the mold, a magnetic core attached to outside of the mold, a vertical deflection coil wound on the core, and magnetic member means for modifying deflection field distribution, interposed between the mold and vertical deflection coil.The deflection device further includes a porous ceramic layer for heat dissipation coated on at least a part of the outer surfaces of the mold, horizontal deflection coil, vertical deflection coil and magnetic member means.

Abstract: A high-performance deflection yoke providing deflection of an electron beam in a CRT at high rates at high deflection angles. The high-performance deflection yoke includes a heat sink contacting the deflection yoke coils to remove the heat produced in the deflection yoke due to core losses and heat produced in the deflection coils due to resistive losses. The heat sink minimizes induced eddy currents and comprises fine wire elements, interwoven and/or in juxtaposition with the deflection coils, wherein the heat created within and picked up by the deflection coils is transferred to the heat sink for dissipation. By minimizing power lost in the heat sink due to inductive heating of the metallic components thereof, the heat sink according to the present invention provides a high-performance deflection yoke having low inductance, high power performance not heretofore practically realizable.

Abstract: A thermal reed switch assembly including two magnetic reed switches having two permanent magnets and at least two semicylindrical thermal magnetic members each having mutually different magnetic tansition points sandwiching the reed switch therebetween. An inner diameter of one thermal magnetic member may be larger than at least a second member therein increasing the sectional area ratio of the members.

Abstract: Magnetic field formers in a cathode ray tube (CRT) deflection yoke for controlling the position of an electron beam in the CRT are secured to and maintained in position on the yoke by means of a foamed hot melt adhesive. An inert gas such as nitrogen or carbon dioxide is introduced in a volumetrically metered manner into a hot melt adhesive which may be polyethylene, polypropylene or any number of other thermoplastics to form a foamed adhesive containing a large volume of gas bubbles. The foamed hot melt fluid is then deposited between the magnetic field formers and various other portions of the deflection yoke to provide magnetic field former support and yoke strength, eliminate deflection yoke hot spots, dampen out yoke vibration modes, and reduce the cost of the deflection yoke.

Abstract: A convergence device for electron beams in a color picture tube includes a pair of four-pole magnet rings, a pair of six-pole magnet rings and a pair of two-pole magnet rings, the absolute value of the temperature coefficient of magnetization of which is equal to or less than 0.05%/.degree. C. measured in a temperature range of 0.degree. C. to 120.degree. C.

Abstract: A air-flow-rate sensor having a thermo-magnetically operated switch including a U-shaped temperature sensitive ferromagnetic piece, a positive temperature characteristic thermister, and two terminal plates, which are stationarily mounted in an opening chamber of an insulator frame. The two terminal plates are for connecting the thermister to an external electric power source and are in contact with respective input electrodes on opposite surfaces of the thermister. One of the two terminal plates is formed in a generally arcuate form to elastically press the other terminal plate onto the ferromagnetic piece through the thermister. The thermo-magnetically operated switch is fixedly mounted on the frame by fitting its opposite terminals into grooves formed in the inner wall of the frame. Each terminal plate is also fixed to the frame by fitting both ends into another grooves formed in the inner wall of the frame.

Abstract: When two pieces of magnetic material are clamped together in a magnetic circuit, a silicone rubber piece is used to control the clamping pressure in order not only to prevent material stress at the clamping surfaces but also to compensate for the effects of temperature expansion of the magnetic material.

Abstract: In the disclosed driving circuit for a coil, particularly for driving a coil in a device such as a camera whose shutter blades are driven with electro-magnetic force generated by a current flowing through the coil and a magnetic field in which the coil is positioned, a voltage approximately proportional to the absolute temperature is applied across the terminals of the coil so as to produce temperature compensation of the coil current.

Abstract: Thermal compensators comprising at least one metallic alloy in amorphous form which are especially useful in stabilizing magnetic devices under conditions of changing ambient operating temperature are provided.

Abstract: A temperature compensated magnetic damping assembly for providing a braking torque on an electroconductive disk of an induction device includes a pair of permanent magnets each having an easy axis of magnetization. Each permanent magnet provides two easy flux paths parallel to the easy axis of magnetization and separated by a dead zone. The permanent magnets are juxtaposed about a predetermined space through which the disk rotates such that the easy flux paths are perpendicular to the disk, and are aligned such that the magnetic flux passes twice through the disk in opposite directions. Flux return plates are provided adjacent to each of the permanent magnets so as to provide a flux path parallel to the disk and linking the two easy flux paths of each of the permanent magnets. In this configuration, a highly-efficient, substantially square magnetic flux loop is provided. One of the flux return plates is movable relative to the adjacent permanent magnet so as to provide series adjustment of the damping torque.

Abstract: A serial printer head is provided which comprises a sandwich structure (1,3,5) of a first circular yoke plate (1), a cylindrical magnet (3) and a ring shaped second yoke plate (5); a plurality of electromagnets (2,4) positioned on the first yoke plate (1) at predetermined angle intervals; an armature-print-needle assembly (7,8,9,10) having a circular resilient spring (7), a plurality of armatures (8) and a plurality of print needles (9) placed on the sandwich structure (1,3,5) so that the sandwich structure (1,3,5), electromagnets (2,4) and the armatures (8) provide first a substantially closed magnetic path; and an adjusting yoke (12) attached to the sandwich structure (1,3,5). The adjusting yoke (12) has the magnetic characteristics that the magnetic reluctance increases as the temperature increases. Although the flux generated by the permanent magnet (3) is changed due to the change of the temperature, that flux change is compensated for by the presence of the adjusting yoke (12).

Abstract: In a magnetic field generator mounted about a neck of a cathode ray tube for focusing an electron beam and made up of a permanent magnet, a magnetic field adjusting mechanism for adjusting field intensity produced by the permanent magnet and a magnetic member adapted to compensate for a temperature characteristic of the permanent magnet, the temperature characteristic compensating member is located at a position not affected by magnetic flux adjusted by the magnetic field adjusting mechanism.

Abstract: A watthour meter damping assembly includes a U-shaped magnetic yoke and a pair of highly coercive and anisotropic permanent magnets projecting in facing relationship from the ends of the yoke. Opposing pole faces of the magnets form an air gap receiving a meter disc to be magnetically retarded. A single temperature compensator extends over the pole faces of the permanent magnets to form a compensating shunt flux path around the air gap. The compensator and magnetic yoke extend substantially parallel to each other from the inner and outer pole faces, respectively, of the magnet pair.

Abstract: A balancing scale or electromagnetically compensated weighing apparatus has an independently actuatable and temperature-sensitive magnetic device for balancing a load member; the magnetic device forms a magnetic circuit, and includes a temperature-sensitive corrective device affecting the circuit in at least two locations, so as to substantially temperature-compensate the magnetic circuit over a predetermined temperature range.

Abstract: A temperature compensated accelerometer of the type having a permanent magnet, moving coil rebalance system is disclosed. A cylindrical permanent magnet and surrounding sleeve produce radial magnetic fields in annular regions in which are located rebalance coils on a suspended bobbin. A noninductive temperature sensing winding on the magnet is connected in a bridge input circuit to an amplifier which produces a current in an auxillary winding for augmenting the fields produced by the permanent magnet so as to maintain constant magnetic field strength in the annular regions.

Abstract: A core type magnetron is disclosed wherein a permanent magnet is provided in an anode resonator surrounding a cathode, characterized in that said permanent magnet has a reversible temperature coefficient of which is variable depending on the operating point and which is adapted such that it is utilized at the operating point where said reversible temperature coefficient has the value of zero or close thereto.

Abstract: A temperature responsive reed switch having magnetic reed pieces, a permanent magnet disposed near a contact of the reed switch and being magnetized in an axial direction of the reed switch, two temperature responsive magnetic materials disposed adjacent the ends of the permanent magnet in the axial direction of the reed switch and a magnetic yoke disposed adjacent the outer surfaces of the temperature responsive magnetic material.

Abstract: An electromagnetic force applying device comprises a core with an annular air gap, a coil for creating a radial magnetic field in the air gap and an armature ring movable axially in the air gap. The core and the ring are of different magnetic materials with different coefficients of thermal expansion so that the force applied to the ring when a given current flows through the coil varies with temperature.

Abstract: A metal strip on a magnetic core body, provided with an air gap, for a coil means, is connected to a surface of the magnetic material such that an assembly similar to a bimetal is formed. Variations in temperature then cause variations of the length of the air gap.