Magnetic circuit

About: Magnetic circuit is a research topic. Over the lifetime, 15707 publications have been published within this topic receiving 118099 citations.

Inverse type magnetic flow damper

Abstract: A kind of inversion magnetic current alter amortisseur,which has application in the absorption of vibration of the building structure and the locomotive cars It includes the cylinder body,the piston, the piston rod which connected to it, the confinement gasoline device of the both sides of the cylinder body and the cylinder cap, there has magnetic current alternative liquid in the void of the cylinder body, and institutes the magnetizer that generates the magnetic field and the energizing coil and the electromagnet magnetic circuit component which is unitized of the running void, the cylinder body is composed of the master cylinder, or the master cylinder and the set jar, or the master cylinder and bypass jar, its character is:Institutes both the energizing coil and the permanent magnet magnetic circuit, composes the compounded magnetic circuit with the energizing coil and the permanent magnetic field, and also institutes the administer void in the electromagnet circuit, and when the power is cut, the most of the permanent magnetic field that generated by the permanent magnet will pass through the running void, so the amortisseur can work at the great amortization condition The component of the electromagnet circuit may set at the pertinent position in terms of the different cylinder body This kind of amortisseur can joint with the controlled structure, fulfills the semiactivly controlled with the absorption of vibration

Shielded electromagnetic acoustic transducers

Abstract: Disclosed is an electromagnetic acoustic transducer, including a source of magnetic flux for establishing a static magnetic field, an electrical conductor for conducting an alternating current in the static magnetic field, and an electrically conductive, nonmagnetic shield disposed between the source of magnetic flux and the conductor.

Relaxation of Trapped High Magnetic Field in 100 m-long Class $rm MgB_2$ Solenoid Coil in Persistent Current Mode Operation

Abstract: This paper reports on the relaxation of trapped magnetic field in a MgB2 solenoid coil in PC mode operation. For PC mode operation, we fabricated a closed loop circuit with a MgB2 coil, a PCS and some superconducting joints. The MgB2 coil was fabricated employing a 100 m-long PIT processed MgB2 wire using a wind & react method. The critical current Ic of the coil reached 166 A and the coil was able to generate a maximum magnetic field of about 2.5 T at 4.2 K without an external field. The PCS was fabricated employing a long NbTi wire stabilized Cu-Ni alloy. The joints were fabricated between MgB2 and NbTi conductor, between NbTi (PCS) and NbTi conductor. The resistance of all fabricated joints was estimated to be less than 1.0times10-13 Omega. In PC mode operation with the closed loop circuit, a magnetic field of 1.46 T was trapped for about 50000 s (above 12 hr.) without any detectable decay. These results demonstrate the possible use of the MgB 2 superconductor for applications such as MRI superconducting magnet

A Distributed Magnetic Circuit Approach to Analysis of Multiphase Induction Machines With Nonsinusoidal Supply

Abstract: A 15-phase induction machine supplied by voltages with third-order harmonic injection has nonsinusoidal magnetomotive forces distribution. This paper introduces a distributed magnetic circuit approach to perform magnetic circuit calculations in order to determine the magnetizing inductance for both the fundamental and third-harmonic component. The proposed approach divides the half-pole or one-pole machine model into a large number of fan-shaped sectors. The air-gap flux densities for all sectors are then solved iteratively. The fundamental and third-harmonic inductances are extracted via Fourier analysis of air-gap flux density distribution. Calculated fundamental and third-order harmonic inductances are compared with those obtained from no-load tests of a 15-phase prototype induction machine. The good agreement between calculated and experimental results verifies the accuracy of the presented method.

Fully clamped coupled inductors in power conversion circuits

Abstract: The subject invention reveals improvement methods for circuits that use a coupled inductor wherein overshoot and ringing associated with leakage inductance of said coupled inductor is entirely eliminated by addition of non-dissipative active clamp networks that clamp each winding during each operating state of a power supply containing said coupled inductor. A further improvement applicable to zero voltage switching circuits that employ an inductor for driving a zero voltage turn on switching transition of a switch enables elimination of said inductor and preserves said zero voltage switching properties by adding leakage inductance to a coupled inductor without any adverse overshoot and ringing effects associated with said leakage inductance. The subject invention also reveals a coupled inductor with enhanced leakage inductance which can be used with said other improvements. Example circuits including zero voltage switching flyback and forward converters which require only one magnetic circuit element are revealed. Zero voltage switching tapped inductor buck and boost converters with a single magnetic circuit element are also revealed.