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Magnetic circuit
About: Magnetic circuit is a research topic. Over the lifetime, 15707 publications have been published within this topic receiving 118099 citations.
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TL;DR: In this article, the magnetic field due to current flowing in complex shapes of current-carrying conductors have been calculated analytically, simulated using finite-element analysis (FEA), and measured using the superconducting quantum interference device technique (SQUID).
91 citations
TL;DR: In this article, the authors proposed a nonlinear model for three-phase transformers with three legs with and without task under DC bias based on electric and magnetic circuit theory, where the wave shapes of the three magnetizing currents of (asymmetric) transformers are dependent on the phase sequence.
Abstract: This paper proposes a new model for three-phase transformers with three legs with and without task under DC bias based on electric and magnetic circuit theory. For the calculation of the nonsinusoidal no-load currents, a combination of time and frequency domains is used. The analysis shows that (1) asymmetric three-phase transformers with three legs generate magnetizing currents with triplen harmonics not being of the zero-sequence type. (2) The wave shapes of the three magnetizing currents of (asymmetric) transformers are dependent on the phase sequence. (3) The magnetic history of transformer magnetization-due to residual magnetization and hysteresis of the tank-cannot be ignored if a DC bias is present and the magnetic influence of the tank is relatively strong, e.g., for oil-cooled transformers. (4) Symmetric three-phase transformers with three legs generate no-load currents without triplen harmonics. (5) The effects of DC bias currents (e.g., reactive power demand, harmonic distortion) can be suppressed employing symmetric three-phase transformers with three legs including tank. Measurements corroborate computational results; thus this nonlinear model is valid and accurate.
90 citations
TL;DR: In this paper, a magnetic circuit model for an interior permanent magnet (IPM) synchronous machine is presented, which includes each portion of magnetic flux paths, especially the leakage flux paths around the magnets in the rotor.
Abstract: This paper presents a magnetic circuit model for an interior permanent magnet (IPM) synchronous machine. The model includes each portion of magnetic flux paths, especially the leakage flux paths around the magnets in the rotor. The magnetic field quantities are expressed analytically in terms of the reluctance ratio /spl beta/ and the leakage flux ratios /spl eta/ and /spl lambda/. It is shown that the width and the iron saturation level of the iron bridge have an important effect on the magnetic field distribution within the motor. Numerical results confirm the validity of the analytical model.
90 citations
TL;DR: In this paper, the effects of a moderate magnetic field applied to a SQUID magnetometer and introduces the concept of flux dam, which is a weak link or Josephson junction in series with the pickup loop which allows magnetic flux to enter and leave the inside of the superconducting loop easily for moderate changes in magnetic field.
Abstract: This letter discusses the effects of a moderate magnetic field applied to a SQUID magnetometer and introduces the invention of the ‘‘flux dam’’ A flux dam is a weak link or Josephson junction in series with the pickup loop which allows magnetic flux to enter and leave the inside of the superconducting loop easily for moderate changes in magnetic field This largely prevents the flux lines from entering and being pinned in the superconducting parts of the magnetometer which would create extra low frequency noise SQUID magnetometers with flux dams in the pickup loop can be operated in the Earth’s magnetic field without a significant increase in low frequency flux noise
90 citations
02 Oct 1993
TL;DR: A permeance-tube-based method is developed to allow simple algebraic magnetic circuit analysis and associated prediction of flux linkages regardless of the level of magnetic saturation of the ferromagnetic structure.
Abstract: Unlike its rotary counterpart, the linear switched reluctance machine (LSRM) lends itself to double-sided excitation and multiple translator (or "rotor") configurations that can yield high-force density designs suitable for controlled linear motion in hostile environments. This paper presents the particular design of a 6:4, double-sided, double-translator LSRM that develops 5.1 lb/in/sup 2/ of air gap force shear. The work develops a permeance tube based method to allow simple algebraic magnetic circuit analysis and associated prediction of flux linkages regardless of the level of magnetic saturation of the ferromagnetic structure. Theoretical static thrust predictions are made based on the calculation of change in stored magnetic coenergy per unit distance of translator movement. Laboratory testing of a proof-of-principle LSRM, built up to verify the theoretical predictions, shows that the calculated and measured average thrust values agree within reasonable error over the range of excitation. >
90 citations