1006 results about "Skin effect" patented technology

A transformer is provided with a coil portion containing primary windings and a secondary winding. Cores sandwich the coil portion. Each of these windings includes a toroidal-shaped portion that is formed by winding flat type wires in a toroidal shape and by overlapping these flat type wires. Edge portions of this flat type wire are derived from the toroidal-shaped portion respectively. A plurality of windings and the cores are arranged along an overlapping direction of the flat type wires. employed, By this structure, a copper loss caused by the skin effect can be reduced and the electromagnetic coupling conditions between the windings can be improved.

A fixing apparatus an aspect of the present invention includes, a heating object which generates the heat by a magnetic flux produced from a coil which generates a predetermined magnetic flux by electromagnetic induction in accordance with a frequency of an input current, and a pressurization mechanism which can provide a predetermined pressure to the heating object, and a coil of the heating object is formed of a litz wire obtained by twisting the number of conductors having a small cross section which are not affected by the skin effect caused due to the frequency of the input current, the number of which allows passage of a quantity of current to be inputted.

The invention relates to a method for recognizing parameters of asynchronous motor. The stator resistance of motor is measured by a method of DC volt-ampere. The rotor resistances as well as leakage inductance of stator and rotor of motor is obtained by short circuit test. Mutual inductance of stator and rotor of motor can be taken from method of no-load test. Compensating voltage drop in on state, switch time delay and dead time raises the accuracy and stability of recognized parameter. The resistance values of rotor at frequency of rating sliding difference are calculated by method of two points through test of locked rotor at two frequencies. Since skin effect is overcome, the resistance values of rotor are accurate enough so as to meet the requirement of vector control system completely.

The invention provides a method for identifying asynchronous motor parameters offline under a stationary state. The method comprises the steps of firstly, identifying a stator resistance value of a motor by using a direct current voltammetry; and then taking a single-phase rated-frequency alternating voltage and a single-phase low-frequency alternating voltage as an excitation source respectively to perform a single-phase alternating current test, obtaining steady-state response currents of the motor through detection, and obtaining a motor stator leakage inductance, a rotor inductance, a rotor resistance and a stator-rotor mutual inductance value through calculation. According to the method, calculation is performed in strict accordance with a motor classic equivalent circuit model, the accuracy is high, additionally, the condition that a reference voltage output by a motor controller is not accordant with the actual voltage and effects of the skin effect are further considered, corresponding compensation measures are taken, and the parameter identifying accuracy is further improved.

The invention discloses a motor parameter detection method and a motor parameter detection device. The motor parameter detection method comprises the following steps: opening the circuit of one of phase windings of a motor; detecting stator leakage inductance and rotor leakage inductance; applying rated voltage with higher frequency than rated power between the other two phases of the motor; and detecting the stator leakage inductance and the rotor leakage inductance according to the computational formula of the stator leakage inductance and the rotor leakage inductance. The invention provides the off-line motor parameter detection method and the motor parameter detection device under the static condition of the rotor of an induction motor, which achieve high accuracy of motor parameter detection through reducing the influences of voltage errors and a skin effect as long as current or voltage with different frequencies is applied between the two phases of the motor in sequence.

A apparatus and apparatus for compensating for video insertion loss due to transmission over long twisted pair cable lines is presented. Transmission of video over twisted pair cable is advantageous because of its superior cost advantage over coaxial cable. However, twisted pair cables have significant loss characteristics at the higher frequencies (i.e., broadband) compared to coaxial cables. At a transmitter station, the video signal is amplified in the high frequency region for possible skin effect losses thereby brute forcing the high frequency components to the receiving station. At the receiver station, the video signal is further compensated for diffusion line and skin effect losses. The total skin effect compensation applied in both the transmitter and receiver stations is such that the square root of frequency characteristics of skin effect losses is compensated for. Thus, at the receiving station, the high frequency compensation added at the transmitter to brute force the high frequency components to the receiving station may be removed if found excessive. Additionally, compensation is included to adjust for skew that may occur because of irregularities between the various twisted pairs used to transmit the individual video components. Non-minimum phase type filters are used to inject delay into the faster arriving signals so that they may coincide in phase with later arriving signals resulting in a true reproduction of the video.

Benzopyranone compounds having the following structure: wherein R1, X, Y and n are as defined here, are disclosed. The compounds of formula (I), wherein R1 is H, can be prepared by demethylation of the corresponding phenolic methyl ether. The compounds are useful for treating a bone-resorbing disease, cancer, arthritis or an estrogen-related condition such as breast cancer, osteoporosis, endometriosis, cardiovascular disease, hypercholesterolemia, prostatic hypertrophy, prostatic carcinomas, obesity, hot flashes, skin effects, mood swings, memory loss, and adverse reproductive effects associated with exposure to environmental chemicals or natural hormonal imbalances.

In order to design on-chip interconnect structures in a flexible way, a CAD approach is advocated in three dimensions, describing high frequency effects such as current redistribution due to the skin-effect or eddy currents and the occurrence of slow-wave modes. The electromagnetic environment is described by a scalar electric potential and a magnetic vector potential. These potentials are not uniquely defined, and in order to obtain a consistent discretization scheme, a gauge-transformation field is introduced. The displacement current is taken into account to describe current redistribution and a small-signal analysis solution scheme is proposed based upon existing techniques for static fields in semiconductors. In addition methods and apparatus for refining the mesh used for numerical analysis is described.

Coil is made to be disposed with gap opposed to the surface of wafer, and wafer stage is made to move in X and Y direction and R and θ direction. When supplying an alternating current to coil with the frequency swept by impedance analyzer, the magnetic field made to be induced in coil will operate on the conductive film of wafer. By changing a parameter (a frequency or an angle) influencing the skin effect of the conductive film and giving the parameter to coil, the state where a magnetic field is not made to penetrate relatively the film of wafer and the state where the magnetic field is made to penetrate relatively the film can be formed. From the variation of various values corresponding to the eddy current induced based on the change of state influenced by the skin effect of the conductive film, the film thickness of wafer can be measured with sufficient accuracy.

The invention discloses a producing method for copper coated aluminum row profile, and the method comprises following steps in turn: 1) cleaning, 2) drying, 3) head rolling, 4) clearance drawing, 5) bimetal combining furnace heating, 6) high frequency induction heating, 7) hot drawing, 8) heat preserving, 9) oxide layer washing and 10) packing. Beneficial effects of the invention are: the metal is not oxidized during drawing. The high frequency induction skin effect enables two kinds of metal with significantly different melting points reaching the critical point of composite metal metallurgy integrating temperature simultaneously, so a permanent compact metallurgical combining is realized between the two kinds of metals. The density of the profile in the invention is only 36.5% to 41.6% of that of pure copper rows, the length of the profile is 2.45 to 2.70 times of that of pure copper rows, the tensile strength of the profile is over 1.6 to 2 times of that of pure copper rows, and the specific resistance is between 0.027310 ohm question mark mm2/m(-40 Celsius system) and 0.041506 ohm question mark mm2/m(70 Celsius system).

The invention discloses a brushless direct current motor electromagnetic torque observation method based on a self-adapting slip-form observer, belonging to the control field of permanent magnet motors. The observation method comprises the following steps of: constructing a state space equation of a brushless direct current motor in an alpha-beta coordinate system based on easily-observing signals, such as motor rotating speed, each phase current of a stator, each ground voltage of the stator, rotor position, and the like; observing a counter emf (Electromotive Force) of the brushless direct current motor in the alpha-beta coordinate system in real time by using the slip-form observer; meanwhile online identifying a stator resistance parameter of the brushless direct current motor to eliminate the influence of a resistance parameter error on counter emf observation; and finally calculating the electromagnetic torque of the brushless direct current motor in real time according to the counter emf, the current and the rotating speed. In the invention, when the stator resistance parameter is unknown or a stator resistance changes due to the influences of temperature and skin effect, the counter emf and the electromagnetic torque of the brushless direct current motor can be accurately observed, the problem of the traditional method influenced by the resistance parameter is solved, and an accurate torque feedback value can be provided for the torque close loop control of the brushless direct current motor.

The invention discloses a preparation method of a special composite contact belt, wherein, two or more clean strips with matched properties are heated rapidly in protective atmosphere according to a certain speed by a brushing mechanism and a high frequency induction heater, continuously rolled and compounded according to a certain processing rate under the condition of atmosphere protection such as hydrogen, nitrogen, argon, etc. after a die is precisely located, and formed a long strip with two or more layers. After the long strip carries out heat treatment, the long strip is rolled to the regulated thickness and divided into a plurality of micro sized strips on a precise stripping device. The micro sized strips are prepared into special composite contact strips after being shaped, rolled and molded by a precise die. The preparation method of the invention has the advantages that close combination can be formed and at the same time performance of material is protected by making use of skin effect of the high frequency induction heating; no large rolling equipment is needed; strength of interlayer combination is high and stable; longer strips can be continuously compounded; production efficiency is high by combination of precise stripping technology, thus being suitable for production in large amount.

An inductor includes a core made from a metallic magnetic material, a wire wound around the core, a pair of outer electrodes coupled to respective end portions of the wire, a shielding member arranged so as to cover a top face and three or more side faces of the core, and an insulating member arranged between the core and the shielding member and having thermal conductivity. The thickness of the shielding member is set by applying the electric resistivity and permeability of the shielding member and the frequency of noise desired to be shielded to an expression for determining the depth of a skin of skin effect. The thickness of the insulating member is set according to the breakdown voltage of the insulating member and the voltage with which insulation is desired to be ensured under a use environment of the inductor.

An apparatus for personal aesthetic skin treatment by RF voltage. The apparatus includes an RF voltage supply and a disposable patch with an assembly of individual electrodes operative to contact segments of the skin and deliver to each contact RF voltage. The RF voltage may be supplied to each of the electrodes according to a predetermined experimentally established skin treatment protocol. The treatment RF current generated by the applied RF voltage heats the skin and is applied intermittently to different electrodes being in contact with the skin in an order and duration sufficient to cause the desired skin effect and enable proper cooling of earlier treated skin segments. The selected protocol ensures safe non-ablative skin treatment parameters.

An electrical conductor for transmission of electrical power, having a total cross-section equal to or above 10 mm² and comprising a plurality of stranded filamentary members, where at least one of the filamentary members is made from microalloyed copper or microalloyed aluminium having annealing temperatures higher than 250° C., and has the side surface thereof totally coated with a fluorinated polymer. The conductor has a better behavior relative to the skin effect and allows operation at high temperatures. Furthermore, if the electrical conductor is suspended, it has a smaller sag and prevents or reduces the accumulation of ice and/or snow.

A surge-suppression system utilizing a hybrid design comprised of metal oxide varistors, silicon avalanche diodes, a fuse element, filter capacitor and multiple surge planes and surge paths to dissipate and divert transient over-voltages away from sensitive electronic equipment. These multiple surge conduction paths provide redundant parallel planes which optimize the skin-effect phenomena, which is the flow of electrical current at the conductor surface. This design provides a very low impedance which produces a high performance surge-suppression system.

Provided is a shunt resistor, which controls an influence of skin effect by high frequency current. The shunt resistor has a rod-shaped resistance body (11), and a pair of main electrode (12), of another material from the resistance body, wherein end faces of the resistance body and the main electrode are bonded. The resistance body (11) has a hole (11a) going through in direction where main electrodes are disposed, or a high resistance part (11b) going through at its axis portion that is highly resistive than outer part, and low resistance part (11c) that is formed in outer of the high resistance part. It is preferable that outer circumference of the resistance body is circle-shaped. Since, current doesn't flow fundamentally in the through hole or the high resistance part, fluctuation band in the current pathway can be reduced. Therefore, change of resistance value by skin effect by high-frequency current can be reduced.

An electric wire having a conductive portion with grooves on the surface thereof to increase a surface area of the conductive portion for enlarging the skin effect in high frequency current and enhancing the transmissibility and the space factor in high frequency current is provided. The conductive portion 1a being made of an electric conductive material is formed on the surface 1a with a convexo-concave surface 3 to provide predetermined amount of grooves 2 or concave portions 20 having a predetermined section with a predetermined depth W extending in a direction of thickness or toward a center of the conductive portion on the surface of the conductive portion along lengthwise the conductive portion