Magnetic circuit

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

Optimized reduction of the magnetic field near Swedish 400 KV lines by advanced control of shield wire currents. Test results and economic evaluation

Abstract: The design of existing Swedish 400 kV lines is described, especially as regards parameters influencing the characteristics of the magnetic field. Field reduction possibilities by introducing controlled shield wire currents on the relatively new delta configuration are analyzed together with results from tests on a line in operation. The use of a regulator to optimize each shield wire current separately in order to compensate for asymmetry is demonstrated. >

A combined finite element-state space modeling environment for induction motors in the ABC frame of reference: the blocked-rotor and sinusoidally energized load conditions

Abstract: The combined finite element-state space (CFE-SS) modeling environment was used to predict the performance of a 1.2 hp, three-phase case-study squirrel cage induction motor under blocked rotor and typical load operating conditions. The nature of this CFE-SS environment allows one to rigorously account for the impact of space harmonics generated by the magnetic circuit, winding, and cage geometric, as well as layout peculiarities and magnetic saturation, on the current and torque profiles, and ohmic losses in the stator armature and cage. This includes the ability to predict the profiles of connector and bar currents. The results of the CFE-SS simulations compare favorably with blocked rotor and load experimental test data. Potential capabilities of this CFE-SS modeling environment, and its use in impacting motor design decisions, are discussed in the light of reported findings. >

Analytical Calculation of Back EMF Waveform for Linear PM Motors in Slotted and Slotless Structures

Abstract: This paper presents the analytical calculation of back electromotive force (EMF) waveform for linear permanent magnet motors in either slotted or slotless structures. The predictions are based on the analysis of the 2-D magnetic field distributions and the 3-D end effects. In the slotted structure, the relative permeance function obtained by the Schwarz-Christoffel conformal mapping is used to take into account the effects of slotting and to calculate the air-gap flux density. Subsequently, to evaluate the leakage components resulting from the slot opening, slot opening factor is introduced to reflect the elements which do not follow the intended path to produce the back EMF. In the slotless structure, the effective values of the magnetic field quantities, together with the extended theory of winding factors, are employed to evaluate the back EMF waveform. For the analysis of the axial end effects, the 3-D leakage factor is incorporated into the analytical solutions by adding the end leakage permeance to the entire magnetic circuit models. The validity of the analytical results for each topology is confirmed by 2-D finite element and experimental results.

A Practicable Method for Ferromagnetic Object Moving Direction Identification

Abstract: The direction of a moving target is an important piece of information in many wireless sensor network (WSN) applications, such as in boundary security, traffic flow control, etc. Due to its robustness, the magnetic sensor can be used to detect a passing ferromagnetic object. By using the orthogonality of two perpendicularly placed sensing units in a monomer magnetic sensor, a linear algorithm based on a magnetic dipole model to identify the ferromagnetic object's moving direction is introduced in this paper. It has been successfully applied in real WSN applications to reduce the numbers of nodes, and prolong the lifetime of the network. Both simulation and field experiments show it has strong noise immunity and more than 95% correction rate in direction detecting.

Accelerator with closed electron drift

Abstract: The invention is related to a plasma technology field, in particular, to plasma accelerators, used in a space technology, in scientific researches and in industry. A technical result is that the accelerator has an increased lifetime which is achieved by reducing in wear of discharge chamber walls. An accelerator with closed electron drift includes a ring anode 1 with an anode cavity 2, a magnetic circuit 3, field coils 4 and pole tips 5 with a ring interpole gap, external 6 and internal 7 ring cathodes, a cathode-compensator 8, a power supply 9, a means forming positive gradient of magnetic field 10 which can be formed by walls of the anode 1 made of ferromagnetic material. Outlet edges of the anode 1 are provided with nozzles 11 made of nonmagnetic material; a nozzle shape coincides with shape of the magnetic field line of force which is tangential to outlet edges of the anode. The anode 1 is connected with a system supplying with gaseous active substance by means of the hole 12.