Inductor materials

X X cote material for various inductors, transformers, and TV deflection units... 

The leakage inductance (represented by a small inductor in series with a winding) causes some flux not to couple with the core, but to escape into the surrounding air and materials. Its behavior is not governed by its associated transformer or inductor, hence any reflected impedance to the winding in question does not affect the behavior of the leakage inductor. 

The bath is normally at a temperature in the range 620-710°C, depending on whether the coating material is an aluminium-silicon alloy (for use in high-temperature conditions) or pure aluminium (for corrosion prevention). It is heated by inductors, by resistance heaters or by an external flame. The pot will usually be refractory lined unless cast-iron pots are needed to ensure adequate heat transfer from an external flame. As molten aluminium is extremely aggressive towards ferrous metals, replacement of cast-iron pots is fairly frequent. Refractory-lined pots obviously do not have this drawback, although the bath hardware, in particular the sinker roll and support mechanism, will still be attacked and need replacement at intervals. 

Usually, inductors and transformer used at low temperatures have nonmagnetic cores, since materials with a high permeability at room temperature usually show a strong... 

To model the transformer, an ideal center-tapped transformer is combined with a nonlinear core model for the F material. As this circuit counts on the saturation of the core, a SPICE primitive inductor will not work. By adding this nonlinear core model across the input of the center-tapped transformer, the magnetizing inductance and saturation characteristics of the core are realized. 

Inductors -magnetic matenals as [MAGNETIC MATERIALS - BULK] (Vol 15) -magnetic matenals as [MAGNETIC MATERIALS - BULK] (Vol 15) -use of glassy metals [GLASSY METALS] (Vol 12)... 

Functional fibres, filaments and yams are the basic building blocks of electrotextiles. The textile industry has demonstrated a remarkable capability to incorporate both natural and man-made filaments into yarns and fabrics to satisfy a wide range of physical parameters which survive the manufacturing process and are tailored to specific application environments. Electronic components can be fabricated within and/or on the surface of filaments and can subsequently be processed into functional yams and woven into fabrics. Passive components such as resistors, capacitors and inductors can be fabricated in several different manners. Diodes and transistors can be made on long, thin, flat strands of silicon or formed in a coaxial way. Progress has been made in the development of fibre batteries and fibre-based solar cells. In addition, a variety of actuated materials (piezoelectric, etc.) can be made into multiple long strands (filaments) and subsequently be woven into fabric. 

Soft ferrites are used for the manufacture of inductor cores (pot cores) for telecommunications, low-power transformers and high-flux transformers such as television line output transformers, and as television tube scanning yokes (Fig. 9.17). The more important material characteristics for these and other applications are now discussed with emphasis on the influence of composition and microstructure. The review paper by A. Broese van Groenou et al. [9] and the monograph by E.C. Snelling [10] are recommended to supplement the discussion. 

The resistivity p of an inductor core material is important because it determines eddy current losses. In general room temperature resistivities of ferrites lie in the range 10 —106Qm, many orders of magnitude higher than that of the most resistive of the ferromagnetic alloys (about 8x10 7 Qm). Typical resistivity-temperature data for MnZn and NiZn ferrites are shown in Fig. 9.22. For both... 

There are two ferrite material properties which were not discussed in Section 9.3.1 but which are important in the inductor context they are the temperature and time stabilities of the permeability which, of course, determine the stability of the inductance. The temperature coefficient of permeability must be low, and this has been achieved for certain MnZn ferrite formulations as indicated in Fig. 9.18. A small residual temperature coefficient of inductance can be compensated by a suitable coefficient of opposite sign in the capacitance of the resonant combination. 

In the use of ferrites as inductors for tuned circuits, the Q of the materials is of prime importance. Wide-band transformers are also used extensively in communications systems, for example to transform signal voltages and to provide impedance matching and d.c. isolation of one part of a circuit from another. Pulse transformers are of increasing importance because of the rapidly growing use of pulsed signals in communications technology. Since a pulse can... 

Inductors. Inductors have many turns of conductor wrapped around a cylinder if the cylinder is of a magnetic material, then the inductance L is much increased. L is measured in henrys. Two intertwined turns of wire will have mutual inductance M a current through one loop will induce a current in the second loop. The units of M are the same as for L. 

Transformers have a magnetic material (typically, Fe) and two inductors wrapped around it the magnet increases by a few thousandfold the mutual inductance Mbetween the two loops. Transformers are used to increase (step-up transformer) or decrease (step-down transformer) the voltage in the second circuit relative to the first. 

An inductor is commonly a coiled conducting wire wrapped around a core (e g., ferromagnetic material) with two terminals. When current passes through the inductor, magnetic flux is produced, resulting in inductance. The number of loops, the size of each loop, and the core material all affect the inductance value. 

Figure 3.36 shows the heating principle of the zone refining purification procedure and also introduces the geometric and material conditions that characterize the process. It also shows how the stick transfers heat to the contiguous medium. For a correct introduction to this problem, we assume that the production of heat by the inductor has Gaussian behaviour, so, for the heat generation rate, we can write Eq. (3.124) where the source amplitude (watt/m ) is A, f(t) is a dimensionless function that keeps the maximum temperature for the inductor constant and kj and k2 are the constants with dimension ... 

For many traditional ceramics such as structural elements (tiles, bricks, etc.), white-wares, (tableware, sanitaryware, etc.), and common refractories, the raw materials are naturally occurring minerals, and moderate levels of impurities are tolerated. More specialized technical ceramics such as electronic ceramics (substrates, electronic packages, capacitors, inductors, etc.) or high performance structural ceramics (silicon carbide, silicon nitride, etc.) demand low or controlled levels of impurities and make use of higher purity powders often made by more specialized techniques. 

Such an inductor generates a temperature field of almost square symmetry. The main slit in the inductor, which forms the current loop, however, is not completely equivalent to the other three slits as seen in Fig. 3.9b. Furthermore, the surface tension surrounds the corners by minimizing the melt surface, which is not desired because the goal are quadratic wafers directly cut from the crystals. Additionally, on the straight sides, where the horizontal curvature is almost zero, growth instabilities can occur. Regarding the application for the solar industry, which would save material loss and the costs of cutting the round crystal into a square one, it is essential to get a stable... 

A. Muiznieks, A. Rudevics, K. Lacis, H. Riemann, A. Liidge, F.W. Schulze, B. Nacke, Square-like silicon crystal rod growth by FZ method with especially 3D shaped HF inductors. International Scientific Colloquium Modelling for Material Processing, Riga, 2006... 

Figure 11.1 shows an example of the schematic diagram of FLA equipment [9]. The flash lamps, e.g., xenon lamps, are energized by discharging a capac-itor/inductor bank flash power supply [10], resulting in millisecond-order radiation onto wafers, to increase the temperature of target material by light... 

In attempting to generally reduce parasitics and their associated losses, we may notice that these are often dependent on various external factors — temperature for one. Some losses increase with temperature — for example the conduction loss in a mosfet. And some may decrease — for example the conduction loss in a bjt (when operated with low currents). Another example of the latter type is the ESR-related loss of a typical aluminum electrolytic capacitor, which also decreases with temperature. On the other hand, some losses may have rather strange shapes. For example, we could have an inverted bell-shaped curve — representing an optimum operating point somewhere between the two extremes. This is what the core loss term of many modern ferrite materials (used for inductor cores) looks like — it is at its minimum at around 80 to 90°C, increasing on either side. 

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