Magnetic core

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

Magnetic properties of soft magnetic powder composites at higher frequencies in comparison with electrical steels

Abstract: To ensure a fair comparison of magnetic properties between electrical steels and SMC the measurements should be done on samples with a similar geometry. At a certain transition point of frequency the specific core losses of SMC become lower then those of electrical steels. Thus, the application of SMC instead of electrical steels in electrical machines operating at elevated frequencies can improve their efficiency.

Method of measuring changes in impedance of a variable impedance load by disposing an impedance connected coil within the air gap of a magnetic core

Abstract: The present invention relates to a method and apparatus for remotely detecting impedance. It is specifically adapted for use on a polishing machine wherein the end point of polishing for removing a surface layer during the processing of semiconductor substrates is detected. A first, or stationary coil having a high permeability core is wound having an air gap and an AC voltage is applied to the stationary coil to provide a magnetic flux in the air gap. A second coil is mounted for rotation on the polishing table, in a position to periodically pass through the air gap of the stationary coil as the table rotates. The second coil is connected at its opposite ends to contacts which are embedded in the surface of the polishing wheel. The contacts are positioned to engage the surface of the substrate which is being polished and provide a load on the second or rotating coil. The rotating coil, when it is in the air gap of the stationary coil, will perturb the flux field therein as a function of the resistance of the load caused by the contacts contacting either a conducting surface or a non-conducting surface. This perturbance of the flux field is measured as a change in the induced voltage in the stationary coil which in turn is converted to a signal which is processed to indicate the end point of polishing, the end point being when a metallic layer has been removed to expose a dielectric layer therebeneath or, conversely, when a dielectric layer has been removed to expose a metallic layer therebeneath.

Rotary armature and method of forming armature coil

Abstract: A central conductor portion of a coil is formed with a potbelly-shaped cross-sectional form and a flat-shaped face of an insulated coating film of the potbelly-shaped cross-sectional form coil is made thinner than an arc-shaped face of the insulated coating film of the potbelly-shaped cross-sectional form coil. An insulated coating wire having a circular-shaped cross-sectional form is formed to a coil having a potbelly-shaped cross-sectional form by rolling process at a normal temperature. A dead space in a slot is lessened and the magnetic resistance of a magnetic core is decreased, thereby a small size and a high output electric motor can be obtained. A method of forming a rotary armature coil having a high space factor in the slot can be attained.

Trip device comprising at least one current transformer

Abstract: A trip device comprises at least one current transformer for supplying power to electronic circuits. The current transformer comprises a magnetic circuit, surrounding a primary conductor, a secondary winding wound onto a part of the magnetic circuit forming a core, and a magnetic shunt branch connected on the magnetic core. The magnetic shunt comprises an air-gap. When the current flowing in the primary conductor is of low value, the magnetic flux stopped by the air-gap flows essentially via the core of the secondary winding. At high current levels the induction is greater and a large part of the magnetic flux passes through the shunt via the air-gap. The current transformer has a non-linear current response which limits excess power supplied to the electronic circuits and dissipated in the transformer. The trip device is useful, for example, in a circuit breaker.