515:
eddy currents. Finer particles allow operation at higher frequencies, as the eddy currents are mostly restricted to within the individual grains. Coating of the particles with an insulating layer, or their separation with a thin layer of a binder, lowers the eddy current losses. Presence of larger particles can degrade high-frequency performance. Permeability is influenced by the spacing between the grains, which form distributed air gap; the less gap, the higher permeability and the less-soft saturation. Due to large difference of densities, even a small amount of binder, weight-wise, can significantly increase the volume and therefore intergrain spacing.
506:) that are non-crystalline or glassy. These are being used to create high-efficiency transformers. The materials can be highly responsive to magnetic fields for low hysteresis losses, and they can also have lower conductivity to reduce eddy current losses. Power utilities are currently making widespread use of these transformers for new installations. High mechanical strength and corrosion resistance are also common properties of metallic glasses which are positive for this application.
355:
1141:
1314:
1037:
421:
lamination. Since the current in an eddy current loop is proportional to the area of the loop, this prevents most of the current from flowing, reducing eddy currents to a very small level. Since power dissipated is proportional to the square of the current, breaking a large core into narrow laminations reduces the power losses drastically. From this, it can be seen that the thinner the laminations, the lower the eddy current losses.
133:
782:
1129:
1326:
1017:
675:, makes low audio noise. Loses inductance with increasing temperature, unlike the other materials; can be exploited by combining with other materials as a composite core, for temperature compensation. Saturation flux of about 1 tesla. Good temperature stability. Used in switching power supplies, pulse and flyback transformers, in-line noise filters, swing chokes, and in filters in
1257:
452:, offering better magnetic properties than GNO in one direction. As the magnetic field in inductor and transformer cores is always along the same direction, it is an advantage to use grain oriented steel in the preferred orientation. Rotating machines, where the direction of the magnetic field can change, gain no benefit from grain-oriented steel.
939:
1771:. The loops flow perpendicular to the magnetic field axis. The energy of the currents is dissipated as heat in the resistance of the core material. The power loss is proportional to the area of the loops and inversely proportional to the resistivity of the core material. Eddy current losses can be reduced by making the core out of thin
1191:
971:
955:
1117:
923:
896:
884:
410:
1203:
653:
to compensate capacitance in long telephone lines. It is usable up to about 200 kHz to 1 MHz, depending on vendor. It is still used in above-ground telephone lines, due to its temperature stability. Underground lines, where temperature is more stable, tend to use ferrite cores due to their
662:
An alloy of about 50–50% of nickel and iron. High energy storage, saturation flux density of about 1.5 tesla. Residual flux density near zero. Used in applications with high DC current bias (line noise filters, or inductors in switching regulators) or where low residual flux density is needed (e.g.
913:
E-shaped core are more symmetric solutions to form a closed magnetic system. Most of the time, the electric circuit is wound around the center leg, whose section area is twice that of each individual outer leg. In 3-phase transformer cores, the legs are of equal size, and all three legs are wound.
529:
Powdered iron is the cheapest material. It has higher core loss than the more advanced alloys, but this can be compensated for by making the core bigger; it is advantageous where cost is more important than mass and size. Saturation flux of about 1 to 1.5 tesla. Relatively high hysteresis and eddy
514:
Powder cores consist of metal grains mixed with a suitable organic or inorganic binder, and pressed to desired density. Higher density is achieved with higher pressure and lower amount of binder. Higher density cores have higher permeability, but lower resistance and therefore higher losses due to
272:
In some cases the losses are undesirable and with very strong fields saturation can be a problem, and an 'air core' is used. A former may still be used; a piece of material, such as plastic or a composite, that may not have any significant magnetic permeability but which simply holds the coils of
603:
The as-prepared particles, "E-type"and have onion-like skin, with concentric shells separated with a gap. They contain significant amount of carbon. They behave as much smaller than what their outer size would suggest. The "C-type" particles can be prepared by heating the E-type ones in hydrogen
420:
magnetic cores are made of stacks of thin iron sheets coated with an insulating layer, lying as much as possible parallel with the lines of flux. The layers of insulation serve as a barrier to eddy currents, so eddy currents can only flow in narrow loops within the thickness of each single
1336:
The ring core may also be composed of two separate C-shaped hemispheres secured together within a plastic shell, permitting it to be placed on finished cables with large connectors already installed, that would prevent threading the cable through the small inner diameter of a solid ring.
1787:
By definition, this category includes any losses in addition to eddy-current and hysteresis losses. This can also be described as broadening of the hysteresis loop with frequency. Physical mechanisms for anomalous loss include localized eddy-current effects near moving domain walls.
537:
The binder used is usually epoxy or other organic resin, susceptible to thermal aging. At higher temperatures, typically above 125 °C, the binder degrades and the core magnetic properties may change. With more heat-resistant binders the cores can be used up to 200 °C.
705:. The grain size of the powder reaches down to 10–100 nanometers. The material has very good performance at lower frequencies. It is used in chokes for inverters and in high power applications. It is available under names like e.g. Nanoperm, Vitroperm, Hitperm and Finemet.
1656:
1008:"E" and "I", are stacked with the "I" against the open end of the "E" to form a 3-legged structure. Coils can be wound around any leg, but usually the center leg is used. This type of core is frequently used for power transformers, autotransformers, and inductors.
389:) limits the eddy currents to circulate within each individual lamination, reducing the total current. In this diagram the field and currents are shown in one direction, but they actually reverse direction with the alternating current in the transformer winding.
646:, and 17% iron. Very low core loss, low hysteresis and therefore low signal distortion. Very good temperature stability. High cost. Maximum saturation flux of about 0.8 tesla. Used in high-Q filters, resonant circuits, loading coils, transformers, chokes, etc.
2112:
Losses in magnetic materials can be characterized by the
Steinmetz coefficients, which however do not take into account temperature variability. Material manufacturers provide data on core losses in tabular and graphical form for practical conditions of use.
727:
are used for high-frequency applications. The ferrite materials can be engineered with a wide range of parameters. As ceramics, they are essentially insulators, which prevents eddy currents, although losses such as hysteresis losses can still occur.
1888:
1333:
The ring is essentially identical in shape and performance to the toroid, except that inductors commonly pass only through the center of the core, without wrapping around the core multiple times.
530:
current loss, operation limited to lower frequencies (approx. below 100 kHz). Used in energy storage inductors, DC output chokes, differential mode chokes, triac regulator chokes, chokes for
1492:
field for the material, which has the form of a closed loop. The net energy that flows into the inductor expressed in relationship to the B-H characteristic of the core is shown by the equation
491:
in hydrogen atmosphere in a magnetic field; subsequent sharper bends disrupt its grain alignment, leading to localized loss of permeability; this can be regained by repeating the annealing step.
2302:"How to choose Iron Powder, Sendust, Koolmu, High Flux and MPP Cores as output inductor and chokes : CWS Coil Winding Specialist, manufacturer of transformers, inductors, coils and chokes"
1498:
740:. This includes coils wound on a plastic or ceramic form in addition to those made of stiff wire that are self-supporting and have air inside them. Air core coils generally have a much lower
1749:
249:
material in the center of the coil can increase the magnetic field by hundreds or thousands of times; this is called a magnetic core. The field of the wire penetrates the core material,
1166:. The shape of a pot core is round with an internal hollow that almost completely encloses the coil. Usually a pot core is made in two halves which fit together around a coil former (
1295:
cores), specialized machinery is required for automated winding of a toroidal core. Toroids have less audible noise, such as mains hum, because the magnetic forces do not exert
1480:. This process causes losses, because the domain walls get "snagged" on defects in the crystal structure and then "snap" past them, dissipating energy as heat. This is called
801:. The coil is wound around the rod, or a coil form with the rod inside. Moving the rod in or out of the coil changes the flux through the coil, and can be used to adjust the
2233:
2027:
663:
pulse and flyback transformers, the high saturation is suitable for unipolar drive), especially where space is constrained. The material is usable up to about 200 kHz.
1401:
487:
to reach their magnetic properties, and lose them when subjected to mechanical or thermal abuse. For example, the permeability of mu-metal increases about 40 times after
2095:
441:
is used in transformer cores. Further increase in silicon concentration impairs the steel's mechanical properties, causing difficulties for rolling due to brittleness.
317:
and so does not remain magnetised when the field is removed, which is often important in applications where the magnetic field is required to be repeatedly switched.
1924:
253:
it, so that the strong magnetic field of the core adds to the field created by the wire. The amount that the magnetic field is increased by the core depends on the
1946:
328:
circulating within it, closed loops of electric current in planes perpendicular to the field. The current flowing through the resistance of the metal heats it by
1234:). The coil is wound through the hole in the torus and around the outside. An ideal coil is distributed evenly all around the circumference of the torus. The
2071:
2049:
1998:
1972:
1242:
of circular loops inside the core, and the lack of sharp bends will constrain virtually all of the field to the core material. This not only makes a highly
1081:
A planar core consists of two flat pieces of magnetic material, one above and one below the coil. It is typically used with a flat coil that is part of a
101:
by a factor of several hundred times what it would be without the core. However, magnetic cores have side effects which must be taken into account. In
1057:
Again used for iron cores. Similar to using an "E" and "I" together, a pair of "E" cores will accommodate a larger coil former and can produce a larger
541:
Iron powder cores are most commonly available as toroids. Sometimes as E, EI, and rods or blocks, used primarily in high-power and high-current parts.
298:(DC) electromagnets and in some electric motors; and it can create a concentrated field that is as much as 50,000 times more intense than an air core.
1288:. The main drawback that limits their use for general purpose applications is the inherent difficulty of winding wire through the center of a torus.
1810:
2513:
1661:
This equation shows that the amount of energy lost in the material in one cycle of the applied field is proportional to the area inside the
1321:
rod with connection wires glued to the ends. On the right, a molded ferrite rod with holes, with a single wire threaded through the holes.
2658:
768:
are still present. Air cores are also used when field strengths above around 2 Tesla are required as they are not subject to saturation.
2677:
2137:
1221:
761:
2687:
2610:
2355:
521:
The surface of the particles is often oxidized and coated with a phosphate layer, to provide them with mutual electrical insulation.
2538:
2488:
2463:
2435:
2408:
2365:
2333:. Göteborg, Sweden: Department of Energy and Environment, Division of Electric Power Engineering, Chalmers University of Technology
1065:. If an air gap is required, the centre leg of the "E" is shortened so that the air gap sits in the middle of the coil to minimize
848:
Like a cylindrical rod but is square, rarely used on its own. This type of core is most likely to be found in car ignition coils.
1775:
which have an insulating coating, or alternatively, making the core of a magnetic material with high electrical resistance, like
586:, particularly at very high frequencies. Carbonyl iron has lower losses than hydrogen-reduced iron, but also lower permeability.
332:, causing significant power losses. Therefore, solid iron cores are not used in transformers or inductors, they are replaced by
90:
to be concentrated in the core material. The magnetic field is often created by a current-carrying coil of wire around the core.
1949:
157:
2575:
1651:{\displaystyle W=\int {\left(nA_{c}{\frac {dB(t)}{t}}\right)\left({\frac {H(t)l_{m}}{n}}\right)dt}=(A_{c}l_{m})\int {HdB}}
875:
core to make a square closed core, the simplest closed core shape. Windings may be put on one or both legs of the core.
1277:
1250:
1243:
1179:
1070:
837:
617:
685:
The material was invented in Japan in 1936. It is usable up to about 500 kHz to 1 MHz, depending on vendor.
2380:
1675:
518:
Lower permeability materials are better suited for higher frequencies, due to balancing of core and winding losses.
393:
In order to reduce the eddy current losses mentioned above, most low frequency power transformers and inductors use
2682:
624:
1768:
1353:
value of a core configuration is frequently specified by manufacturers. The relationship between inductance and A
1171:
218:
582:. This is equivalent to a microscopic laminated magnetic circuit (see silicon steel, above), hence reducing the
682:
Absence of nickel results in easier processing of the material and its lower cost than both high-flux and MPP.
1804:
densities. The equation has three loss components: hysteresis, residual, and eddy current, and it is given by
1299:
on the core. The core is only in compression or tension, and the circular shape is more stable mechanically.
2107:
1776:
1760:
1477:
1438:, some of the power that would ideally be transferred through the device is lost in the core, dissipated as
1318:
613:
265:
can cause frequency-dependent energy losses, different core materials are used for coils used at different
2567:
676:
488:
287:
156:
in it. The drawing shows a section through the core. The purpose of the core is to provide a closed high
2327:
1665:. Since the energy lost in each cycle is constant, hysteresis power losses increase proportionally with
574:
between 50 kHz and 200 MHz. Carbonyl iron powders are basically constituted of micrometer-size
1265:
1082:
1027:
579:
306:
254:
35:
2254:
Inoue, A.; Kong, F. L.; Han, Y.; Zhu, S. L.; Churyumov, A.; Shalaan, E.; Al-Marzouki, F. (2018-01-15).
1066:
2662:
2255:
2197:
2127:
210:
98:
20:
2005:
2328:"Powder Material for Inductor Cores, Evaluation of MPP, Sendust and High flux core characteristics"
1463:
472:. They can be manufactured as stampings or as long ribbons for tape wound cores. Some alloys, e.g.
448:, grain-oriented (GO) and grain non-oriented (GNO), GO is most desirable for magnetic cores. It is
321:
118:
102:
87:
2648:
1779:. Most magnetic cores intended for power converter application use ferrite cores for this reason.
1363:
354:
790:
238:
59:
2157:
1140:
324:(AC) applications such as transformers and inductors, the changing magnetic field induces large
589:
A popular application of carbonyl iron-based magnetic cores is in high-frequency and broadband
2616:
2606:
2534:
2509:
2484:
2459:
2431:
2425:
2404:
2398:
2361:
2275:
2215:
2078:
1005:
765:
620:
320:
Due to the electrical conductivity of the metal, when a solid one-piece metal core is used in
43:
437:
of the metal, up to four times higher. The higher resistivity reduces the eddy currents, so
2584:
2267:
2205:
1899:
757:
724:
672:
337:
126:
83:
2301:
1454:, the loss in the windings. Iron losses are often described as being in three categories:
1313:
1036:
1931:
1662:
1481:
1473:
1285:
1090:
1086:
745:
694:
671:
An alloy of 6% aluminium, 9% silicon, and 85% iron. Core losses higher than MPP. Very low
499:
110:
2201:
313:
at ambient temperature.) Annealed iron is used because, unlike "hard" iron, it has low
117:
in applications such as transformers and inductors. "Soft" magnetic materials with low
2588:
2056:
2034:
1983:
1957:
1296:
1239:
484:
302:
295:
234:
214:
177:
the magnetic field lines "bulge" out, so the field strength is less than in the core:
132:
94:
71:
55:
39:
2256:"Development and application of Fe-based soft magnetic bulk metallic glassy inductors"
1325:
2671:
1469:
1042:
828:
from one end of the rod to the other. The air path ensures that the inductor remains
583:
567:
559:
553:
445:
438:
398:
349:
329:
250:
246:
242:
222:
122:
79:
75:
47:
2653:
1146:
Exploded view that shows the spiral track made directly on the printed circuit board
1128:
165:– magnetic field in the core will be approximately constant across any cross section
1764:
1308:
1281:
806:
719:
650:
531:
460:
A family of specialized alloys exists for magnetic core applications. Examples are
325:
310:
258:
241:. A coil without a magnetic core is called an "air core" coil. Adding a piece of
196:
114:
2568:"Magnetic Measurements at Low Flux Densities Using the Alternating Current Bridge"
2381:
http://www.jmag-international.com/catalog/101_ChokeCoil_CurrentCharacteristic.html
2271:
781:
752:
that occur in magnetic cores. The absence of normal core losses permits a higher
697:
alloy of a standard iron-boron-silicon alloy, with addition of smaller amounts of
616:
have higher permeability but lower Q than carbonyl iron. They are used mostly for
1763:, the changing magnetic field induces circulating loops of current in it, called
1451:
1423:
1246:
1163:
1097:
1062:
604:
atmosphere at 400 °C for prolonged time, resulting in carbon-free powders.
594:
563:
469:
449:
434:
394:
374:
230:
106:
67:
51:
1026:
cores, a plastic bobbin and two clips. The bobbin has pins to be soldered to a
1016:
562:, a highly pure iron, have high stability of parameters across a wide range of
2132:
1975:
1772:
1435:
1001:
948:
core allows for construction of inductors or transformers with a lower profile
821:
802:
741:
639:
417:
333:
314:
262:
2279:
2219:
301:
Iron is desirable to make magnetic cores, as it can withstand high levels of
2620:
1797:
1666:
1273:
1175:
833:
749:
477:
465:
266:
31:
1357:
number in the linear portion of the magnetisation curve is defined to be:
817:
is used once the inductor has been tuned to prevent the core from moving.
544:
Carbonyl iron is significantly more expensive than hydrogen-reduced iron.
1883:{\displaystyle {\frac {R_{\text{ac}}}{\mu L}}=aB_{\text{max}}f+cf+ef^{2}}
1431:
1427:
1235:
1231:
1159:
1058:
798:
753:
590:
571:
461:
226:
63:
1256:
2186:"New Determinations of the Saturation Magnetization of Nickel and Iron"
702:
503:
473:
430:
148:
in a typical magnetic core transformer or inductor, with the iron core
2210:
2185:
1472:
of the core material changes by expansion and contraction of the tiny
1406:
where n is the number of turns, L is the inductance (e.g. in nH) and A
1264:
It is popular for applications where the desirable features are: high
785:
Ferrite rods are simple cylinders of ferrite that can be wound around.
86:. The high permeability, relative to the surrounding air, causes the
1269:
1227:
1167:
1094:
829:
809:
to allow adjustment with a screwdriver. In radio circuits, a blob of
698:
643:
575:
2400:
Engineering Basics: Electrical, Electronics and
Computer Engineering
1202:
938:
534:
correction, resonant inductors, and pulse and flyback transformers.
1190:
970:
954:
199:; magnetic field lines which don't follow complete magnetic circuit
2122:
1443:
1324:
1312:
1116:
922:
895:
883:
814:
794:
780:
409:
408:
353:
131:
1291:
Unlike a split core (a core made of two elements, like a pair of
2234:"Metglas® Amorphous Metal Materials – Distribution Transformers"
1801:
1439:
1422:
magnetic field, as it is in devices that use AC current such as
291:
2397:
Thyagarajan, T.; Sendur Chelvi, K.P.; Rangaswamy, T.R. (2007).
1100:
to be constructed for low cost. It is not as ideal as either a
744:
than similarly sized ferromagnetic core coils, but are used in
825:
810:
2449:
2447:
1410:
is expressed in inductance per turn squared (e.g. in nH/n).
630:
Hydrogen-reduced iron cores are often called "power cores".
2659:
How to use ferrites for EMI suppression via
Wayback Machine
824:, but the magnetic field lines must still pass through the
2553:
433:
to iron (around 3%) results in a dramatic increase of the
221:. Coils are widely used in electronic components such as
2403:(3rd ed.). New Age International. pp. 184–185.
2172:
Les composants magnétiques de l'électronique de puissance
820:
The presence of the high permeability core increases the
760:, such as up to a few megahertz. However, losses such as
1000:
Sheets of suitable iron stamped out in shapes like the (
93:
The use of a magnetic core can increase the strength of
2649:
Online calculator for ferrite coil winding calculations
1669:. The final equation for the hysteresis power loss is
1468:
When the magnetic field through the core changes, the
679:(e.g. dimmers) where low acoustic noise is important.
2081:
2059:
2037:
2008:
1986:
1960:
1934:
1902:
1813:
1678:
1501:
1366:
336:
or powdered iron cores, or nonconductive cores like
2508:(Second ed.). Chichester: Wiley. p. 113.
736:A coil not containing a magnetic core is called an
649:The material was first introduced in 1940, used in
257:of the core material. Because side effects such as
2089:
2065:
2043:
2021:
1992:
1966:
1940:
1918:
1882:
1743:
1650:
1395:
2654:What are the bumps at the end of computer cables?
2531:Fundamentals of Power Electronics, Second Edition
2456:Fundamentals of Power Electronics, Second Edition
2184:Danan, H.; Herr, A.; Meyer, A.J.P. (1968-02-01).
600:Carbonyl iron cores are often called "RF cores".
2603:Soft ferrites : properties and applications
2430:. Vol. 2 (4th ed.). IET. p. 195.
1796:An equation known as Legg's equation models the
209:An electric current through a wire wound into a
16:Object used to guide and confine magnetic fields
1744:{\displaystyle P_{H}=(f)(A_{c}l_{m})\int {HdB}}
756:, so air core coils are used in high frequency
152:forming a closed loop, possibly with air gaps
105:(AC) devices they cause energy losses, called
2529:Erickson, Robert; Maksimović, Dragan (2001).
2454:Erickson, Robert; Maksimović, Dragan (2001).
1926:is the effective core loss resistance (ohms),
1158:Usually ferrite or similar. This is used for
8:
2349:
2347:
1045:of the previous figure showing the structure
2533:. Kluwer Academic Publishers. p. 507.
2483:. Tata McGraw-Hill Education. p. 128.
2458:. Kluwer Academic Publishers. p. 506.
2357:Handbook of Modern Ferromagnetic Materials
2321:
2319:
2317:
2315:
1476:it is composed of, due to movement of the
74:, and magnetic assemblies. It is made of
2637:, Marengo, IL: Arnold Engineering Company
2583:(1), Bell Telephone Laboratories: 39–63,
2360:. Springer Science & Business Media.
2209:
2082:
2080:
2058:
2036:
2013:
2007:
1985:
1959:
1933:
1907:
1901:
1874:
1846:
1820:
1814:
1812:
1730:
1718:
1708:
1683:
1677:
1637:
1625:
1615:
1582:
1563:
1530:
1524:
1511:
1500:
1387:
1377:
1365:
748:circuits to prevent energy losses called
2295:
2293:
2291:
2289:
1329:A ferrite ring on a computer data cable.
1255:
840:may be a problem in some circumstances.
397:cores, made of stacks of thin sheets of
2149:
901:The C-shaped core, with rounded corners
217:through the center of the coil, due to
2605:(2nd ed.). London: Butterworths.
2481:Basic Electrical Engineering, Volume 1
2326:Johan Kindmark, Fredrik Rosén (2013).
1484:. It can be seen in the graph of the
1022:Construction of an inductor using two
369:within a solid iron transformer core.
144:created by a current-carrying winding
7:
2029:is the maximum flux density (gauss),
623:and low-frequency chokes, mainly in
2633:Arnold Engineering Company (n.d.),
2138:Toroidal inductors and transformers
2000:is the hysteresis loss coefficient,
1222:Toroidal inductors and transformers
964:core has a cylindrical central leg.
889:A U-shaped core, with sharp corners
2589:10.1002/j.1538-7305.1936.tb00718.x
2506:High-frequency magnetic components
578:of iron coated in a thin layer of
173:– "fringing fields". In the gaps
160:path for the magnetic field lines.
14:
2424:Whitfield, John Frederic (1995).
2354:Goldman, Alex (6 December 2012).
2051:is the residual loss coefficient,
836:occurs at the end of the rod and
476:, are manufactured as powder and
2566:Legg, Victor E. (January 1936),
2504:Kazimierczuk, Marian K. (2014).
2300:others, The Zen Cart™ Team and.
1446:. Core loss is commonly termed
1418:When the core is subjected to a
1201:
1189:
1139:
1127:
1115:
1035:
1015:
969:
953:
937:
921:
894:
882:
597:, especially higher power ones.
294:is used in magnetic assemblies,
2554:Arnold Engineering Company n.d.
2260:Journal of Alloys and Compounds
1280:. One such application is the
1085:. This design is excellent for
483:Many materials require careful
2174:, cours de Supélec, mars 2001
2022:{\displaystyle B_{\text{max}}}
1724:
1701:
1698:
1692:
1631:
1608:
1575:
1569:
1545:
1539:
1317:On the left, a non-adjustable
793:or powdered iron, and used in
385:with insulation between them (
1:
2576:Bell System Technical Journal
2272:10.1016/j.jallcom.2017.08.240
2097:is the eddy loss coefficient.
2073:is the frequency (hertz), and
1170:). This design of core has a
502:is a variety of alloys (e.g.
129:, are usually used in cores.
46:and magnetic devices such as
19:For the computer memory, see
1759:If the core is electrically
1396:{\displaystyle L=n^{2}A_{L}}
1278:electromagnetic interference
1251:electromagnetic interference
1180:electromagnetic interference
1071:electromagnetic interference
863:-shaped cores are used with
838:electromagnetic interference
625:switched-mode power supplies
618:electromagnetic interference
373:Making the core out of thin
2427:Electrical Craft Principles
1238:of this geometry creates a
1108:but costs less to produce.
832:. In this type of inductor
2704:
2678:Electromagnetic components
2190:Journal of Applied Physics
2105:
1461:
1306:
1226:This design is based on a
1219:
980:core is halfway between a
717:
551:
347:
38:used to confine and guide
18:
2688:Electromagnetic radiation
2370:– via Google Books.
2090:{\displaystyle {\ce {e}}}
1769:electromagnetic induction
797:especially for tuning an
1791:
1450:in contradistinction to
777:Straight cylindrical rod
772:Commonly used structures
121:and hysteresis, such as
2601:Snelling, E.C. (1988).
1249:, but also reduces the
1196:A pot core of 'RM' type
677:phase-fired controllers
612:Powdered cores made of
570:levels, with excellent
558:Powdered cores made of
444:Among the two types of
344:Laminated silicon steel
78:metal such as iron, or
2102:Steinmetz coefficients
2091:
2067:
2045:
2023:
1994:
1968:
1942:
1920:
1919:{\displaystyle R_{ac}}
1884:
1745:
1652:
1397:
1330:
1322:
1261:
1253:radiated by the coil.
789:Most commonly made of
786:
414:
413:Typical EI Lamination.
390:
377:parallel to the field
219:Ampere's circuital law
201:
2479:Dhogal, P.S. (1986).
2092:
2068:
2046:
2024:
1995:
1969:
1950:material permeability
1943:
1921:
1885:
1746:
1653:
1398:
1328:
1316:
1259:
1230:(the same shape as a
1083:printed circuit board
1028:printed circuit board
784:
638:An alloy of about 2%
614:hydrogen reduced iron
608:Hydrogen-reduced iron
580:electrical insulation
412:
357:
255:magnetic permeability
135:
36:magnetic permeability
2663:Murata Manufacturing
2128:Magnetic-core memory
2108:Steinmetz's equation
2079:
2057:
2035:
2006:
1984:
1958:
1941:{\displaystyle \mu }
1932:
1900:
1811:
1676:
1499:
1364:
429:A small addition of
99:electromagnetic coil
88:magnetic field lines
21:Magnetic-core memory
2202:1968JAP....39..669D
1755:Eddy-current losses
1464:Magnetic hysteresis
1174:effect, preventing
805:. Often the rod is
634:MPP (molypermalloy)
322:alternating current
103:alternating current
2087:
2063:
2041:
2019:
1990:
1964:
1938:
1916:
1880:
1741:
1648:
1393:
1331:
1323:
1262:
1208:A Regular Pot Core
1089:and allows a high
787:
415:
391:
202:
82:compounds such as
2683:Radio electronics
2515:978-1-118-71779-0
2211:10.1063/1.2163571
2170:Daniel Sadarnac,
2085:
2066:{\displaystyle f}
2044:{\displaystyle c}
2016:
1993:{\displaystyle a}
1967:{\displaystyle L}
1849:
1834:
1823:
1800:core loss at low
1798:magnetic material
1592:
1552:
1488:field versus the
1458:Hysteresis losses
1134:A planar inductor
1122:A planar 'E' core
1053:Pair of "E" cores
766:dielectric losses
758:resonant circuits
658:High-flux (Ni-Fe)
44:electromechanical
32:magnetic material
2695:
2638:
2625:
2624:
2598:
2592:
2591:
2572:
2563:
2557:
2551:
2545:
2544:
2526:
2520:
2519:
2501:
2495:
2494:
2476:
2470:
2469:
2451:
2442:
2441:
2421:
2415:
2414:
2394:
2388:
2378:
2372:
2371:
2351:
2342:
2341:
2339:
2338:
2332:
2323:
2310:
2309:
2297:
2284:
2283:
2251:
2245:
2244:
2242:
2240:
2230:
2224:
2223:
2213:
2181:
2175:
2168:
2162:
2161:
2158:"Soft iron core"
2154:
2096:
2094:
2093:
2088:
2086:
2083:
2072:
2070:
2069:
2064:
2050:
2048:
2047:
2042:
2028:
2026:
2025:
2020:
2018:
2017:
2014:
1999:
1997:
1996:
1991:
1973:
1971:
1970:
1965:
1947:
1945:
1944:
1939:
1925:
1923:
1922:
1917:
1915:
1914:
1889:
1887:
1886:
1881:
1879:
1878:
1851:
1850:
1847:
1835:
1833:
1825:
1824:
1821:
1815:
1783:Anomalous losses
1750:
1748:
1747:
1742:
1740:
1723:
1722:
1713:
1712:
1688:
1687:
1657:
1655:
1654:
1649:
1647:
1630:
1629:
1620:
1619:
1604:
1597:
1593:
1588:
1587:
1586:
1564:
1558:
1554:
1553:
1548:
1531:
1529:
1528:
1474:magnetic domains
1402:
1400:
1399:
1394:
1392:
1391:
1382:
1381:
1205:
1193:
1143:
1131:
1119:
1039:
1019:
996:"E" and "I" core
973:
957:
941:
925:
898:
886:
762:proximity effect
725:Ferrite ceramics
673:magnetostriction
425:Silicon alloying
382:
366:
273:wires in place.
184: <
141:
2703:
2702:
2698:
2697:
2696:
2694:
2693:
2692:
2668:
2667:
2645:
2632:
2629:
2628:
2613:
2600:
2599:
2595:
2570:
2565:
2564:
2560:
2552:
2548:
2541:
2528:
2527:
2523:
2516:
2503:
2502:
2498:
2491:
2478:
2477:
2473:
2466:
2453:
2452:
2445:
2438:
2423:
2422:
2418:
2411:
2396:
2395:
2391:
2386:
2379:
2375:
2368:
2353:
2352:
2345:
2336:
2334:
2330:
2325:
2324:
2313:
2299:
2298:
2287:
2253:
2252:
2248:
2238:
2236:
2232:
2231:
2227:
2183:
2182:
2178:
2169:
2165:
2156:
2155:
2151:
2146:
2119:
2110:
2104:
2077:
2076:
2055:
2054:
2033:
2032:
2009:
2004:
2003:
1982:
1981:
1956:
1955:
1930:
1929:
1903:
1898:
1897:
1870:
1842:
1826:
1816:
1809:
1808:
1794:
1792:Legg's equation
1785:
1757:
1714:
1704:
1679:
1674:
1673:
1663:hysteresis loop
1621:
1611:
1578:
1565:
1559:
1532:
1520:
1516:
1512:
1497:
1496:
1482:hysteresis loss
1466:
1460:
1416:
1409:
1383:
1373:
1362:
1361:
1356:
1352:
1347:
1344:
1311:
1305:
1286:audio amplifier
1260:A toroidal core
1224:
1218:
1213:
1212:
1211:
1210:
1209:
1206:
1198:
1197:
1194:
1156:
1151:
1150:
1149:
1148:
1147:
1144:
1136:
1135:
1132:
1124:
1123:
1120:
1087:mass production
1079:
1055:
1050:
1049:
1048:
1047:
1046:
1040:
1032:
1031:
1020:
998:
993:
992:
991:
990:
989:
974:
966:
965:
958:
950:
949:
942:
934:
933:
926:
911:
906:
905:
904:
903:
902:
899:
891:
890:
887:
854:
852:"C" or "U" core
846:
844:Single "I" core
779:
774:
746:radio frequency
734:
722:
716:
711:
695:nanocrystalline
691:
689:Nanocrystalline
669:
667:Sendust, KoolMU
660:
636:
610:
556:
550:
527:
512:
510:Powdered metals
500:Amorphous metal
497:
458:
427:
407:
380:
364:
352:
346:
284:
279:
235:electric motors
207:
200:
193:
188:
182:
171:
166:
161:
139:
136:Magnetic field
72:recording heads
56:electric motors
42:in electrical,
40:magnetic fields
24:
17:
12:
11:
5:
2701:
2699:
2691:
2690:
2685:
2680:
2670:
2669:
2666:
2665:
2656:
2651:
2644:
2643:External links
2641:
2640:
2639:
2627:
2626:
2612:978-0408027601
2611:
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2539:
2521:
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2471:
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2409:
2389:
2384:
2373:
2366:
2343:
2311:
2306:www.coilws.com
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2163:
2148:
2147:
2145:
2142:
2141:
2140:
2135:
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2118:
2115:
2106:Main article:
2103:
2100:
2099:
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2012:
2001:
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1527:
1523:
1519:
1515:
1510:
1507:
1504:
1462:Main article:
1459:
1456:
1442:and sometimes
1415:
1412:
1407:
1404:
1403:
1390:
1386:
1380:
1376:
1372:
1369:
1354:
1350:
1346:
1342:
1339:
1307:Main article:
1304:
1301:
1297:bending moment
1276:, and minimal
1266:specific power
1240:magnetic field
1220:Main article:
1217:
1214:
1207:
1200:
1199:
1195:
1188:
1187:
1186:
1185:
1184:
1155:
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1133:
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1125:
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1114:
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1111:
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1078:
1075:
1054:
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1033:
1021:
1014:
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1012:
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1010:
997:
994:
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878:
877:
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770:
733:
730:
718:Main article:
715:
712:
710:
707:
690:
687:
668:
665:
659:
656:
635:
632:
609:
606:
552:Main article:
549:
546:
526:
523:
511:
508:
496:
495:Vitreous metal
493:
485:heat treatment
457:
456:Special alloys
454:
426:
423:
406:
403:
361:Eddy currents
348:Main article:
345:
342:
303:magnetic field
296:direct current
283:
280:
278:
275:
223:electromagnets
215:magnetic field
206:
205:Core materials
203:
191:
180:
169:
95:magnetic field
48:electromagnets
30:is a piece of
15:
13:
10:
9:
6:
4:
3:
2:
2700:
2689:
2686:
2684:
2681:
2679:
2676:
2675:
2673:
2664:
2660:
2657:
2655:
2652:
2650:
2647:
2646:
2642:
2636:
2631:
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2608:
2604:
2597:
2594:
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2550:
2547:
2542:
2540:9780792372707
2536:
2532:
2525:
2522:
2517:
2511:
2507:
2500:
2497:
2492:
2490:9780074515860
2486:
2482:
2475:
2472:
2467:
2465:9780792372707
2461:
2457:
2450:
2448:
2444:
2439:
2437:9780852968338
2433:
2429:
2428:
2420:
2417:
2412:
2410:9788122412741
2406:
2402:
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2374:
2369:
2367:9781461549178
2363:
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2329:
2322:
2320:
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2316:
2312:
2307:
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2294:
2292:
2290:
2286:
2281:
2277:
2273:
2269:
2266:: 1303–1309.
2265:
2261:
2257:
2250:
2247:
2235:
2229:
2226:
2221:
2217:
2212:
2207:
2203:
2199:
2196:(2): 669–70.
2195:
2191:
2187:
2180:
2177:
2173:
2167:
2164:
2159:
2153:
2150:
2143:
2139:
2136:
2134:
2131:
2129:
2126:
2124:
2121:
2120:
2116:
2114:
2109:
2101:
2075:
2060:
2053:
2038:
2031:
2010:
2002:
1987:
1980:
1977:
1961:
1954:
1951:
1935:
1928:
1911:
1908:
1904:
1896:
1895:
1894:
1875:
1871:
1867:
1864:
1861:
1858:
1855:
1852:
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1806:
1805:
1803:
1799:
1789:
1782:
1780:
1778:
1774:
1770:
1766:
1765:eddy currents
1762:
1754:
1737:
1734:
1731:
1727:
1719:
1715:
1709:
1705:
1695:
1689:
1684:
1680:
1672:
1671:
1670:
1668:
1664:
1644:
1641:
1638:
1634:
1626:
1622:
1616:
1612:
1605:
1601:
1598:
1594:
1589:
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1579:
1572:
1566:
1560:
1555:
1549:
1542:
1536:
1533:
1525:
1521:
1517:
1513:
1508:
1505:
1502:
1495:
1494:
1493:
1491:
1487:
1483:
1479:
1475:
1471:
1470:magnetization
1465:
1457:
1455:
1453:
1449:
1445:
1441:
1437:
1433:
1429:
1425:
1421:
1413:
1411:
1388:
1384:
1378:
1374:
1370:
1367:
1360:
1359:
1358:
1340:
1338:
1334:
1327:
1320:
1315:
1310:
1302:
1300:
1298:
1294:
1289:
1287:
1283:
1279:
1275:
1271:
1268:per mass and
1267:
1258:
1254:
1252:
1248:
1245:
1241:
1237:
1233:
1229:
1223:
1216:Toroidal core
1215:
1204:
1192:
1183:
1181:
1178:and reducing
1177:
1173:
1169:
1165:
1161:
1153:
1142:
1130:
1118:
1109:
1107:
1106:toroidal core
1103:
1099:
1096:
1092:
1088:
1084:
1076:
1074:
1072:
1068:
1064:
1060:
1052:
1044:
1043:Exploded view
1038:
1029:
1025:
1018:
1009:
1007:
1003:
995:
987:
983:
979:
972:
963:
956:
947:
940:
931:
924:
915:
908:
897:
885:
876:
874:
870:
866:
862:
858:
851:
849:
843:
841:
839:
835:
831:
827:
823:
818:
816:
812:
808:
804:
800:
796:
792:
783:
776:
771:
769:
767:
763:
759:
755:
751:
747:
743:
739:
731:
729:
726:
721:
713:
708:
706:
704:
700:
696:
688:
686:
683:
680:
678:
674:
666:
664:
657:
655:
652:
651:loading coils
647:
645:
641:
633:
631:
628:
626:
622:
619:
615:
607:
605:
601:
598:
596:
592:
587:
585:
584:eddy currents
581:
577:
573:
569:
568:magnetic flux
565:
561:
560:carbonyl iron
555:
554:carbonyl iron
548:Carbonyl iron
547:
545:
542:
539:
535:
533:
524:
522:
519:
516:
509:
507:
505:
501:
494:
492:
490:
486:
481:
479:
475:
471:
467:
463:
455:
453:
451:
447:
446:silicon steel
442:
440:
439:silicon steel
436:
432:
424:
422:
419:
411:
404:
402:
400:
399:silicon steel
396:
388:
384:
376:
372:
368:
360:
356:
351:
350:Silicon steel
343:
341:
339:
335:
331:
330:Joule heating
327:
326:eddy currents
323:
318:
316:
312:
308:
304:
299:
297:
293:
289:
281:
276:
274:
270:
268:
264:
260:
259:eddy currents
256:
252:
248:
247:ferrimagnetic
244:
243:ferromagnetic
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232:
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224:
220:
216:
212:
204:
198:
194:
187:
183:
176:
172:
164:
159:
155:
151:
147:
143:
134:
130:
128:
124:
123:silicon steel
120:
116:
115:eddy currents
112:
108:
104:
100:
96:
91:
89:
85:
81:
80:ferrimagnetic
77:
76:ferromagnetic
73:
69:
65:
61:
57:
53:
49:
45:
41:
37:
33:
29:
28:magnetic core
22:
2634:
2602:
2596:
2580:
2574:
2561:
2556:, p. 70
2549:
2530:
2524:
2505:
2499:
2480:
2474:
2455:
2426:
2419:
2399:
2392:
2376:
2356:
2335:. Retrieved
2305:
2263:
2259:
2249:
2239:25 September
2237:. Retrieved
2228:
2193:
2189:
2179:
2171:
2166:
2152:
2111:
1892:
1795:
1786:
1758:
1660:
1489:
1485:
1478:domain walls
1467:
1447:
1424:transformers
1419:
1417:
1405:
1348:
1335:
1332:
1309:Ferrite bead
1303:Ring or bead
1292:
1290:
1284:for a hi-fi
1282:power supply
1263:
1225:
1164:transformers
1157:
1105:
1101:
1080:
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981:
977:
961:
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912:
872:
868:
864:
860:
856:
855:
847:
819:
788:
737:
735:
723:
720:Ferrite core
692:
684:
681:
670:
661:
654:lower cost.
648:
637:
629:
611:
602:
599:
595:transformers
588:
564:temperatures
557:
543:
540:
536:
532:power factor
528:
520:
517:
513:
498:
482:
459:
443:
428:
416:
392:
386:
378:
370:
362:
358:
319:
309:(up to 2.16
300:
285:
277:Solid metals
271:
231:transformers
208:
197:leakage flux
189:
185:
178:
174:
167:
162:
158:permeability
153:
149:
145:
137:
92:
68:loudspeakers
52:transformers
34:with a high
27:
25:
1773:laminations
1452:copper loss
1436:alternators
1247:transformer
1098:transformer
1077:Planar core
1069:and reduce
1063:transformer
867:or another
750:core losses
470:supermalloy
450:anisotropic
435:resistivity
375:laminations
267:frequencies
251:magnetizing
107:core losses
70:, magnetic
2672:Categories
2337:2017-06-05
2144:References
2133:Pole piece
1976:inductance
1761:conductive
1002:sans-serif
928:Classical
822:inductance
803:inductance
742:inductance
640:molybdenum
480:to shape.
405:Lamination
315:coercivity
307:saturating
263:hysteresis
239:generators
213:creates a
119:coercivity
111:hysteresis
60:generators
2635:MPP Cores
2280:0925-8388
2220:0021-8979
1978:(henrys),
1936:μ
1828:μ
1767:, due to
1728:∫
1667:frequency
1635:∫
1509:∫
1448:iron loss
1432:AC motors
1428:inductors
1414:Core loss
1274:mains hum
1244:efficient
1176:radiation
1172:shielding
1160:inductors
834:radiation
591:inductors
572:Q factors
489:annealing
466:permalloy
418:Laminated
395:laminated
334:laminated
282:Soft iron
227:inductors
109:, due to
64:inductors
2621:17875867
2117:See also
1420:changing
1236:symmetry
1232:doughnut
1154:Pot core
1102:pot core
1093:, small
1067:fringing
1059:inductor
909:"E" core
807:threaded
799:inductor
754:Q factor
738:air core
709:Ceramics
478:sintered
462:mu-metal
381:B, green
305:without
288:annealed
286:"Soft" (
84:ferrites
2198:Bibcode
1974:is the
1948:is the
1777:ferrite
1319:ferrite
1006:letters
791:ferrite
714:Ferrite
703:niobium
621:filters
576:spheres
504:Metglas
474:Sendust
431:silicon
371:(right)
338:ferrite
127:ferrite
2619:
2609:
2537:
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2364:
2278:
2218:
1893:where
1430:, and
1272:, low
1270:volume
1228:toroid
1168:bobbin
1095:volume
984:and a
830:linear
795:radios
699:copper
644:nickel
642:, 81%
468:, and
365:I, red
359:(left)
311:teslas
97:in an
2571:(PDF)
2387:Value
2331:(PDF)
2123:Balun
1444:noise
1349:The A
1345:value
1091:power
815:resin
146:(red)
140:green
125:, or
2617:OCLC
2607:ISBN
2535:ISBN
2510:ISBN
2485:ISBN
2460:ISBN
2432:ISBN
2405:ISBN
2362:ISBN
2276:ISSN
2241:2020
2216:ISSN
1802:flux
1440:heat
1434:and
1162:and
988:core
976:The
960:The
946:EFD'
944:The
932:core
859:and
764:and
701:and
593:and
566:and
525:Iron
292:iron
261:and
237:and
211:coil
113:and
2661:by
2585:doi
2383:, A
2268:doi
2264:731
2206:doi
2015:max
1848:max
1104:or
1061:or
986:pot
962:ETD
871:or
826:air
813:or
811:wax
732:Air
245:or
2674::
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379:(
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190:B
186:B
181:F
179:B
175:G
170:F
168:B
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154:G
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138:(
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