Solenoid

About: Solenoid is a research topic. Over the lifetime, 19278 publications have been published within this topic receiving 114721 citations.

Manifold solenoid valve driven by serial signals

Abstract: In a manifold solenoid valve drive-controlled by serial signals, a solenoid valve itself is provided with a function for receiving serial signals for single valves or double valves so as to simplify assembly and replacement of the manifold solenoid valve. For this purpose, in order to transmit serial signals to solenoid valves through manifold blocks 30 on which solenoid valves 20 are mounted and which are connected, each manifold block 30 is provided with female/male connecting terminals 46a and 46b for transmitting serial signals and a connector 49 for transmitting drive control serial signals to the solenoid valves 20 and supplying drive power for switching a main valve 22. A connector 25 for transmitting and receiving power that is connected to the connector 49 when the solenoid valve 20 is mounted is provided at a position matched to the connector 49 of the manifold block. The solenoid valve 20 is provided with a slave chip 28 that extracts operation signals for solenoid valves from serial signals received through the connectors.

Locating an inaccessible object by detecting horizontal and vertical components of a magnetic field

Abstract: If a solenoid is mounted on an underground object, such as a boring tool, magnetic fields generated by an electric current flowing through that solenoid can be detected by a suitable detector at or above the surface If the axis of the solenoid is tilted, the maximum value of the field is not directly above the solenoid Therefore, the present invention makes use of measured values of horizontal and vertical components of the magnetic field to determine the separation of the detector and the solenoid, and also, by making use of a tilt sensor associated with the solenoid to derive a prediction of the ratio of the horizontal and vertical components of the field at a position vertically above or below the solenoid If that predicted value of the ratio is then compared with the measured value of the ratio, the two will coincide when the detector is vertically above the solenoid Thus, by moving the detector until such coincidence is obtained, the position of the solenoid can be determined

Aharonov-Bohm effect as a scattering event

Abstract: The Aharonov-Bohm effect is reconsidered as a scattering event of an electron by a magnetic field confined in an infinite solenoid of finite radius both in the situation where the solenoid is penetrable as well as impenetrable. We next discuss the validity of the Born approximation for the partial-wave scattering amplitudes and explain why for the cylindrically symmetric $(m=0)$ partial wave the first Born approximation fails in the long-wavelength limit or as the radius of the solenoid shrinks to zero.

Integrated RF inductors with micro-patterned NiFe core

Abstract: Integrated radio-frequency solenoids with micro-patterned magnetic cores for reduced dimensions and compatibility with CMOS/BiCMOS process technology are presented and discussed. It is demonstrated that the use of a ferromagnetic (FM) core leads to a more than 20-fold enhanced inductance per area. This is achieved by tailoring the anisotropy of the FM core and the design of the metal coil structure. Both a higher operating frequency and a larger inductance are obtained by increasing the shape aspect ratio of the FM core and by depositing the magnetic film under an external magnetic field. A reference to an optimum shape anisotropy has been created by measuring the FM core inductors with an external DC magnetic field. An optimum practical trade-off of inductance and operating frequency results from patterning of the FM core.

A novel heat engine for magnetizing superconductors

Abstract: The potential of bulk melt-processed YBCO single domains to trap significant magnetic fields (Tomita and Murakami 2003 Nature 421 517–20; Fuchs et al 2000 Appl. Phys. Lett. 76 2107–9) at cryogenic temperatures makes them particularly attractive for a variety of engineering applications including superconducting magnets, magnetic bearings and motors (Coombs et al 1999 IEEE Trans. Appl. Supercond. 9 968–71; Coombs et al 2005 IEEE Trans. Appl. Supercond. 15 2312–5). It has already been shown that large fields can be obtained in single domain samples at 77 K. A range of possible applications exist in the design of high power density electric motors (Jiang et al 2006 Supercond. Sci. Technol. 19 1164–8). Before such devices can be created a major problem needs to be overcome. Even though all of these devices use a superconductor in the role of a permanent magnet and even though the superconductor can trap potentially huge magnetic fields (greater than 10 T) the problem is how to induce the magnetic fields. There are four possible known methods: (1) cooling in field; (2) zero field cooling, followed by slowly applied field; (3) pulse magnetization; (4) flux pumping. Any of these methods could be used to magnetize the superconductor and this may be done either in situ or ex situ. Ideally the superconductors are magnetized in situ. There are several reasons for this: first, if the superconductors should become demagnetized through (i) flux creep, (ii) repeatedly applied perpendicular fields (Vanderbemden et al 2007 Phys. Rev. B 75 (17)) or (iii) by loss of cooling then they may be re-magnetized without the need to disassemble the machine; secondly, there are difficulties with handling very strongly magnetized material at cryogenic temperatures when assembling the machine; thirdly, ex situ methods would require the machine to be assembled both cold and pre-magnetized and would offer significant design difficulties. Until room temperature superconductors can be prepared, the most efficient design of machine will therefore be one in which an in situ magnetizing fixture is included. The first three methods all require a solenoid which can be switched on and off. In the first method an applied magnetic field is required equal to the required magnetic field, whilst the second and third approaches require fields at least two times greater. The final method, however, offers significant advantages since it achieves the final required field by repeated applications of a small field and can utilize a permanent magnet (Coombs 2007 British Patent GB2431519 granted 2007-09-26). If we wish to pulse a field using, say, a 10 T magnet to magnetize a 30 mm × 10 mm sample then we can work out how big the solenoid needs to be. If it were possible to wind an appropriate coil using YBCO tape then, assuming an Ic of 70 A and a thickness of 100 µm, we would have 100 turns and 7000 A turns. This would produce a B field of approximately 7000/(20 × 10−3) × 4π × 10−7 = 0.4 T. To produce 10 T would require pulsing to 1400 A! An alternative calculation would be to assume a Jc of say 5 × 108A m−1 and a coil 1 cm2 in cross section. The field would then be 5 × 108 × 10−2 × (2 × 4π × 10−7) = 10 T. Clearly if the magnetization fixture is not to occupy more room than the puck itself then a very high activation current would be required and either constraint makes in situ magnetization a very difficult proposition. What is required for in situ magnetization is a magnetization method in which a relatively small field of the order of millitesla repeatedly applied is used to magnetize the superconductor. This paper describes a novel method for achieving this.