Production produce capacitors
Film capacitors , plastic film capacitors , film dielectric capacitors , or polymer film capacitors , generically called "film caps" as well as power film capacitors, are electrical capacitors with an insulating plastic film as the dielectric , sometimes combined with paper as carrier of the electrodes. The dielectric films, depending on the desired dielectric strength, are drawn in a special process to an extremely thin thickness, and are then provided with electrodes. The electrodes of film capacitors may be metallized aluminum or zinc applied directly to the surface of the plastic film, or a separate metallic foil. Two of these conductive layers are wound into a cylinder shaped winding, usually flattened to reduce mounting space requirements on a printed circuit board , or layered as multiple single layers stacked together, to form a capacitor body. Film capacitors, together with ceramic capacitors and electrolytic capacitors , are the most common capacitor types for use in electronic equipment, and are used in many AC and DC microelectronics and electronics circuits.VIDEO ON THE TOPIC: EEVblog #33 1of2 - Capacitor Tutorial (Electrolytic, Tantalum, & Plastic Film)
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Film capacitors , plastic film capacitors , film dielectric capacitors , or polymer film capacitors , generically called "film caps" as well as power film capacitors, are electrical capacitors with an insulating plastic film as the dielectric , sometimes combined with paper as carrier of the electrodes.
The dielectric films, depending on the desired dielectric strength, are drawn in a special process to an extremely thin thickness, and are then provided with electrodes. The electrodes of film capacitors may be metallized aluminum or zinc applied directly to the surface of the plastic film, or a separate metallic foil.
Two of these conductive layers are wound into a cylinder shaped winding, usually flattened to reduce mounting space requirements on a printed circuit board , or layered as multiple single layers stacked together, to form a capacitor body. Film capacitors, together with ceramic capacitors and electrolytic capacitors , are the most common capacitor types for use in electronic equipment, and are used in many AC and DC microelectronics and electronics circuits.
A related component type is the power film capacitor. Although the materials and construction techniques used for large power film capacitors are very similar to those used for ordinary film capacitors, capacitors with high to very high power ratings for applications in power systems and electrical installations are often classified separately, for historical reasons.
As modern electronic equipment gained the capacity to handle power levels that were previously the exclusive domain of "electrical power" components, the distinction between the "electronic" and "electrical" power ratings has become less distinct.
Flattened winding of a "naked" film capacitor before encasement, with a view of collateral metal contact layers "schoopage" and attached terminals.
Film capacitors are made out of two pieces of plastic film covered with metallic electrodes, wound into a cylindrical shaped winding, with terminals attached, and then encapsulated. In general, film capacitors are not polarized, so the two terminals are interchangeable. There are two different types of plastic film capacitors, made with two different electrode configurations:. A key advantage of modern film capacitor internal construction is direct contact to the electrodes on both ends of the winding.
This contact keeps all current paths to the entire electrode very short. The setup behaves like a large number of individual capacitors connected in parallel , thus reducing the internal ohmic losses ESR and the parasitic inductance ESL.
The inherent geometry of film capacitor structure results in very low ohmic losses and a very low parasitic inductance, which makes them especially suitable for applications with very high surge currents snubbers and for AC power applications, or for applications at higher frequencies.
Another feature of film capacitors is the possibility of choosing different film materials for the dielectric layer to select for desirable electrical characteristics, such as stability, wide temperature range, or ability to withstand very high voltages. Polypropylene film capacitors are specified because of their low electrical losses and their nearly linear behavior over a very wide frequency range, for stability Class 1 applications in resonant circuits , comparable only with ceramic capacitors.
For simple high frequency filter circuits , polyester capacitors offer low-cost solutions with excellent long-term stability, allowing replacement of more expensive tantalum electrolytic capacitors.
Typical capacitance values of smaller film capacitors used in electronics start around picofarads and extend upwards to microfarads. Unique mechanical properties of plastic and paper films in some special configurations allow them to be used in capacitors of very large dimensions. The larger film capacitors are used as power capacitors in electrical power installations and plants, capable of withstanding very high power or very high applied voltages.
The dielectric strength of these capacitors can reach into the four-digit voltage range. According to the equation, a thinner dielectric or a larger electrode area both will increase the capacitance value , as will a dielectric material of higher permittivity. The following example describes a typical manufacturing process flow for wound metallized plastic film capacitors.
As an alternative to the traditional wound construction of film capacitors, they can also be manufactured in a "stacked" configuration. So-called multi-layer capacitors MLP, Multilayer Polymer Capacitors can be produced by sawing this large winding into many smaller single segments. Low-cost metallized plastic film capacitors for general purpose applications are produced in this manner.
The point-defect cause of the short-circuit is burned out, and the resulting vapor pressure blows the arc away, too. This property of self-healing allows the use of a single-layer winding of metallized films without any additional protection against defects, and thereby leads to a reduction in the amount of the physical space required to achieve a given performance specification.
In other words, the so-called "volumetric efficiency" of the capacitor is increased. The self-healing capability of metallized films is used multiple times during the manufacturing process of metallized film capacitors.
Typically, after slitting the metallized film to the desired width, any resulting defects can be burned out healed by applying a suitable voltage before winding.
The same method is also used after the metallization of the contact surfaces "schoopage" to remove any defects in the capacitor caused by the secondary metallization process. The "pinholes" in the metallization caused by the self-healing arcs reduce the capacitance of the capacitor very slightly. For larger film capacitors with very high standards for stability and long lifetime, such as snubber capacitors, the metallization can be made with a special fault isolation pattern.
In the picture on the right hand side, such a metallization formed into a "T" pattern is shown. Each of these "T" patterns produces a deliberately narrowed cross-section in the conductive metallization. These restrictions work like microscopic fuses so that if a point-defect short-circuit between the electrodes occurs, the high current of the short only burns out the fuses around the fault. The affected sections are thus disconnected and isolated in a controlled manner, without any explosions surrounding a larger short-circuit arc.
Therefore, the area affected is limited and the fault is gently controlled, significantly reducing internal damage to the capacitor, which can thus remain in service with only an infinitesimal reduction in capacitance.
In field installations of electrical power distribution equipment, capacitor bank fault tolerance is often improved by connecting multiple capacitors in parallel, each protected with an internal or external fuse. Should an individual capacitor develop an internal short, the resulting fault current augmented by capacitive discharge from neighboring capacitors blows the fuse, thus isolating the failed capacitor from the remaining devices.
This technique is analogous to the "T metallization" technique described above, but operating at a larger physical scale.
More-complex series and parallel arrangements of capacitor banks are also used to allow continuity of service despite individual capacitor failures at this larger scale. The rated voltage of different film materials depends on factors such as the thickness of the film, the quality of the material freedom from physical defects and chemical impurities , the ambient temperature, and frequency of operation, plus a safety margin against the breakdown voltage dielectric strength.
But to a first approximation, the voltage rating of a film capacitor depends primarily on the thickness of the plastic film. For example, with the minimum available film thickness of polyester film capacitors about 0. If higher voltages are needed, typically a thicker plastic film will be used. But the breakdown voltage for dielectric films is usually nonlinear.
For thicknesses greater than about 5 mils, the breakdown voltage only increases approximately with the square-root of the film thickness. On the other hand, the capacitance decreases linearly with increased film thickness. For reasons of availability, storage and existing processing capabilities, it is desirable to achieve higher breakdown voltages while using existing available film materials. This can be achieved by a one-sided partial metallization of the insulating films in such a manner that an internal series connection of capacitors is produced.
By using this series connection technique, the total breakdown voltage of the capacitor can be multiplied by an arbitrary factor, but the total capacitance is also reduced by the same factor. The breakdown voltage can be increased by using one-sided partially metallized films, or the breakdown voltage of the capacitor can be increased by using double-sided metallized films. Double-sided metallized films also can be combined with internal series-connected capacitors by partial metallization.
These multiple technique designs are especially used for high-reliability applications with polypropylene films. An important property of film capacitors is their ability to withstand high peak voltage or peak current surge pulses. This capability depends on all internal connections of the film capacitor withstanding the peak current loads up to the maximum specified temperature. The collateral contact layers schoopage with the electrodes can be a potential limitation of peak current carrying capacity.
The electrode layers are wound slightly offset from each other, so that the edges of the electrodes can be contacted using a face contacting method "schoopage" at the collateral end faces of the winding. This internal connection is ultimately made by multiple point-shaped contacts at the edge of the electrode, and can be modeled as a large number of individual capacitors all connected in parallel.
The many individual resistance ESR and inductance ESL losses are connected in parallel , so that these total undesirable parasitic losses are minimized. However, ohmic contact resistance heating is generated when peak current flows through these individual microscopic contacting points, which are critical areas for the overall internal resistance of the capacitor.
If the current gets too high, "hot spots" can develop and cause burning of the contact areas. A second limitation of the current-carrying capacity is caused by the ohmic bulk resistance of the electrodes themselves. For metallized film capacitors, which have layer thicknesses from 0. The surge current rating of film capacitors can be enhanced by various internal configurations. Because metallization is the cheapest way of producing electrodes, optimizing the shape of the electrodes is one way to minimize the internal resistance and to increase the current-carrying capacity.
A slightly thicker metallization layer at the schoopage contact sides of the electrodes results in a lower overall contact resistance and increased surge current handling, without losing the self-healing properties throughout the remainder of the metallization. Another technique to increase the surge current rating for film capacitors is a double-sided metallization. This can double the peak current rating. The double-sided metallized film is electrostatically field-free because the electrodes have the same voltage potential on both sides of the film, and therefore does not contribute to the total capacitance of the capacitor.
This film can therefore be made of a different and less expensive material. For example, a polypropylene film capacitor with double-sided metallization on a polyester film carrier makes the capacitor not only cheaper but also smaller, because the thinner polyester foil improves the volumetric efficiency of the capacitor.
These capacitors use thin metal foils, usually aluminum, as the electrodes overlying the polymer film. The advantage of this construction is the easy and robust connection of the metal foil electrodes.
In this design, the contact resistance in the area of the schoopage is the lowest. However, metal foil capacitors do not have self-healing properties. To avoid breakdowns caused by weak spots in the dielectric, the insulating film chosen is always thicker than theoretically required by the specific breakdown voltage of the material. Radial style with heavy-duty solder terminals for snubber applications and high surge pulse loads. SMD style for printed circuit board surface mounting, with metallized contacts on two opposite edges.
Film capacitors for use in electronic equipment are packaged in the common and usual industry styles: axial, radial, and SMD. Traditional axial type packages are less used today, but are still specified for point-to-point wiring and some traditional through-hole printed circuit boards.
The most common form factor is the radial type single ended , with both terminals on one side of the capacitor body. To facilitate automated insertion , radial plastic film capacitors are commonly constructed with terminal spacings at standardized distances, starting with 2.
Radial capacitors are available potted in plastic cases, or dipped in an epoxy resin to protect the capacitor body against environmental influences. Although the transient heat of reflow soldering induces high stress in the plastic film materials, film capacitors able to withstand such temperatures are available in surface-mounted device SMD packages.
Before the introduction of plastic films, capacitors made by sandwiching a strip of impregnated paper between strips of metal, and rolling the result into a cylinder— paper capacitors —were commonly used; their manufacture started in ,  and they were used from the early 20th century as decoupling capacitors in telecommunications telephony. With the development of plastic materials by organic chemists during the Second World War , the capacitor industry began to replace paper with thinner polymer films.
One very early development in film capacitors was described in British Patent , in German manufacturers such as WIMA, Roederstein , Siemens and Philips were trend-setters and leaders in a world market driven by consumer electronics.
One of the great advantages of plastic films for capacitor fabrication is that plastic films have considerably fewer defects than paper sheets used in paper capacitors. This allows the manufacture of plastic film capacitors with only a single layer of plastic film, whereas paper capacitors need a double layer of paper [ citation needed ]. Plastic film capacitors were significantly smaller in physical size better volumetric efficiency , with the same capacitance value and the same dielectric strength as comparable paper capacitors.
Then-new plastic materials also showed further advantages compared with paper. Plastic is much less hygroscopic than paper, reducing the deleterious effects of imperfect sealing. Additionally, most plastics are subject to fewer chemical changes over long periods, providing long-term stability of their electrical parameters.
Capacitor Manufacturing Best Practices for Increasing Profitability in 2019
Source: TTI, Paumanok article. This MarketEYE article summarizes the historical methods by which capacitor manufacturers have increased profitability in each capacitor dielectric over the past 30 years. The data is sourced from Paumanok Publications, Inc. Fixed and Variable Costs to Produce Capacitors In the worldwide capacitor industry, fixed costs represent about 20 percent of the costs of goods sold while variable costs represent a full 80 percent of CGS. To improve profitability, vendors focus primarily on variable costs, including raw materials, labor, variable overhead and variable manufacturing costs.
A module is a compact construction, including capacitors, magnetic starters and circuit breakers or fusing elements. The maximum capacity of one module is kvar, operating voltage being V. The modules for RPC are delivered completely built-in and ready-for-use, which enables fast ands easy mounting of the modules in a capacitor unit. The regulators have an output relay for capacitor banks and are manufactured in different versions with 5, 7, 8 or 12 control steps from stock if available and by order.
The anode foil, cathode foil, and electrolyte paper are cut to the specified width from the source rolls of the specified length. Leads for contacting the cathode and anode foil electrodes are attached either by crimping or by ultrasonic welding. The electrolytic paper is layered between the anode foil and the electrode foil. A coiled construction separates the electrodes. When the structure is coiled in this manner it is known as an "element. The case is slipped into a sleeve printed with the rated voltage, capacitance, and polarity. After which, the sleeve is heat shrunk on to the case. The specified voltage is applied to grow an anode oxide thin film on the cut surface end and on any flaws in the formed oxide thin film. All units are subjected to functional testing and cosmetic inspection. Non-conforming units are removed from production.
)] и помидоров, однако мы заменили овощи рисом, а все прочее из бакалеи вы можете подобрать. Кроха Николь прошагала возле Элли по всему супермаркету.
На другой стороне за проволочной сеткой, там, где прежде граждане Нового Эдема самостоятельно совершали свои покупки, пять или шесть Тиассо и Линкольнов - все 300-й серии, полностью перепрограммированные правительством Накамуры - расхаживали в проходах, выполняя заказы.
Большинство полок пустовало.
Четверо небесно-голубых созданий с полусферическими макушками, покрытыми дрожащей мозгоподобной субстанцией, сидели на корточках напротив Ричарда, все еще не выпускавшего Никки. Все восемь узловатых антенн, переплетаясь, тянулись к Никки, словно бы они хотели что-то сообщить.
Это не его стиль. Он отправился с Арчи, только чтобы избавить от этого меня". Когда охранник ударил Ричарда и тот упал на пол, она снова дернулась. "План был безнадежен с самого начала, - сказала она себе, когда полицейские Нового Эдема вывели Ричарда и Арчи из дворца Накамуры.
Галилей не отрицает, что ударил Марию несколько раз, она закричала, а потом он придавил ее к полу и занялся трусами. Дверь-то он запер. Бенджи выломал ее плечом, прежде чем наброситься на Галилея. Из-за шума и ущерба, нанесенного оборудованию, Большой Блок явился немедленно, а с ним и куча свидетелей.
Арчи сказал мне, что крохотные жучки и москитоморфы, по сути дела, разговаривают друг с другом на общем языке. И это не. Некоторые из морфов владеют _восемью_ языками различных микросуществ. Сам Арчи способен общаться с сорока другими видами: пятнадцать из них используют основные цвета речи октопауков, остальные - знаковые и химические языки, а также другие области электромагнитного спектра. Сновавший взад-вперед Ричард на миг замер посреди комнаты.
Спросила Николь. - Мы вернемся, как только сумеем. Если никого не окажется. кстати, Николь, оставь в Белой комнате передатчик и включи побольше громкость, а другой положи в детской. Тогда мы сможем узнать, что нас подкарауливают. Как я уже говорил, если они не полезут к нам, мы успеем догнать вас; если же люди Накамуры займут нашу квартиру, мы попробуем пробраться в логово октопауков прямо отсюда.
Спросила Николь. - Нет, я был ошеломлен. Сперва я удивился тому, что и он, и смотритель зоопарка смолчали, но потом вспомнил, что октопауки глухи. Оба они помолчали несколько секунд. - Ричард, ты не должен был слышать этот крик.
Что он боится. - Элли, все это дерьмо, я не психолог, но уверен - едва ли кто-нибудь из нас способен осознать, что сделало с ним это двойное убийство. Могу только отметить: допускаю - и достаточно обоснованно, - что он не сохранит нашу тайну, просто чтобы уклониться от трудного решения. - Макс глубоко затянулся и поглядел на свою молодую приятельницу.
"Неужели я попал не. Должно быть, ошибся тоннелем. - Нет, разум отверг эту мысль, пока он торопливо оглядывал комнату, - это именно та комната. в углу пара перышек и одна из забавных пеленок Никки.
Крошечная светящаяся хижина вблизи него бесследно исчезла. Арчи и четверо людей спустились на землю.
Развлекаешься, - заметил Орел. - Возможно, - усмехнулась Николь. - Просто фантастическая игрушка. Едва не забыла о боли в бедре.
Оба устали, Николь дышала с трудом. - Ричард, мне надо передохнуть. Я теперь не могу носиться как. Ричард и Николь торопливо прошли по пустому и темному коридору около пятидесяти метров. Слева оказалась дверь.
С помощью сушильных и стиральных машин, которые они видели в Новом Эдеме, инопланетяне, спешно организовавшие Гранд-отель, устроили возле кафетерия прачечную самообслуживания. В большой комнате находилось еще две женщины. Наи преднамеренно отправилась в дальний угол комнаты, чтобы переговорить с Николь с глазу на глаз.