Magnetic core

About: Magnetic core is a research topic. Over the lifetime, 30011 publications have been published within this topic receiving 155247 citations.

Finite Element Analysis of Field Distribution and Characteristic Performance of Squirrel Cage Induction Motor with Broken Bars

Abstract: This paper develops the foundations of a technique for diagnosis and characterization of effects of broken bars in squirrel-cage induction motors based on the time-stepping coupled finite-element approach. These studies are performed by using the model to compute healthy case, one-broken-bar fault, and two adjacent broken bars fault performance data, which contains stator starting current waveforms, the current density on the bars, the magnetic force distribution on the rotor bars, and the distribution of magnetic field. Meanwhile, the iron core loss distributions on the rotor tooth adjacent to broken bars are computed, and the harmonic component of air-gap flux density is analyzed. From this data, the faulty signatures are extracted. Theoretical approach together with experimental results derived from a two-pole 1.1 kW induction motor confirms the validity of the proposed method. Furthermore, this method, which could help to develop diagnostics of broken bars and performance evaluation of induction motors, has great potential in future applications

Repetitive power pulse generator with fast rising pulse

Abstract: A solid-state pulse generator using a split magnetic core transformer is described. In one embodiment, the solid-state drive circuit uses MOSFETs switching a blumlein to produce a desired input pulses in a primary winding of the split magnetic core. The pulse length is determined primarily by the characteristics of the blumlein and the split core transformer. The “on” time of the solid-state devices can exceed the output pulse length, thereby reducing the chance of damaging voltage spikes. The use of a split magnetic core allows several solid-state drive circuits to be used in parallel to produce a single output pulse. In one embodiment, each solid-state drive circuit drives a separate single-turn primary winding of a split magnetic core transformer. In one embodiment, each core of the split core transformer has one primary winding. The separate cores of the split core transformer are provided with a single secondary winding that couples all of the cores to produce a relatively high-voltage output pulse with relatively few turns in the secondary winding.

Multiple turn low profile magnetic component using sheet windings

Abstract: A magnetic component (i.e. inductor or transformer) utilizes sheet winding patterns designed to enhance component assembly and maximize utilization of the core window areas. The windings are obtained from a copper sheet from which sheet winding patterns are obtained by etching, stamping or cutting the copper sheet. These winding patterns are contoured to fit precisely into the window area of the core of the magnetic component so that the window area is fully utilized. Basic symmetrical copper sheet patterns are used and these are sequentially stacked and combined to achieve multiple turn windings. These assembled winding components are connected to a bobbin which includes pins at its periphery to interconnect the copper sheet winding patterns to obtain the desired number of turns of the windings. The bobbin structure supports the component on a circuit board with the magnetic core of the component protruding through an aperture in the printed circuit board in order to permit a low profile mounting for the component.

Three coil bridge transformer

Abstract: The magnetic core of the transformer is an E--E shaped core. The primary winding of the transformer is divided into three substantially identical planar coils, each coil being wound on one of the three separate core posts. The coils are wired in series such that a current in the primary winding will induce substantially identical magnetic fluxes in the two outer core posts, and an opposite flux in the center post. The secondary of the transformer is formed by a contact plate and a conductor frame which provide conducting paths through the window regions of the E--E core. The bottom of the core is mounted in a recess in the conductor frame. Positioned within in the conductor frame are four rectifiers which make electrical connections to the secondary contact plate. When the transformer delivers power, the voltage on the primary winding will be divided 1/4 on each of the outer coils and 1/2 on the center coil post. During this time only two of the rectifiers will be conducting current. During freewheel times, with no primary voltage, the load current will divide evenly among the four rectifiers. During commutate intervals, between freewheel and on times, the voltage on the primary winding will divide evenly among the three coils. This novel transformer permits a switch mode power supply to supply more power while providing more even cooling.

Thin-film magnetic head having a portion of the upper magnetic core coplanar with a portion of the lower magnetic core

Abstract: A thin-film magnetic head comprising a lower magnetic core formed on a substrate, an upper magnetic core formed on the lower magnetic core with a magnetic gap therebetween, and a coil interposed between the lower magnetic core and the upper magnetic core as insulated from the lower magnetic core and the upper magnetic core, characterized in that at least either of the lower magnetic core and the upper magnetic core comprises a front body of a magnetic pole facing a magnetic recording medium and a rear body of a magnetic pole having part thereof superposed on the front body of the magnetic pole, the rear body of the magnetic pole is disposed as recessed from the head surface facing the medium and held in contact with the front body of the magnetic pole in a plane, the plane is terminated at a rear of the end of the front body of the magnetic pole, and the rear body of the magnetic pole has a shape curved or bent in the direction opposite to the magnetic gap, and further the front body of the magnetic pole is composed of a magnetic member embedded in a trench formed in advance in an insulating layer.