DE2624724A1 - ELECTRIC CAPACITOR - Google Patents

Description

L i ο e π tia - Patent-Verwaltungs-GmbH 6000 Frankfurt / Ma in 70, Theodor-Stern-Kai 1

- ΗΝ 76/1 31.5 = 1976 - ΡΤ-Π-Hs / rh

Electric capacitor

The present invention relates to an electrical, nichtiuprärnierten, plastic packaged capacitor whose Kondennatorwickel consists of metallised einseitif Isolierstofffoli ^f -n.

It is known to encase capacitor windings with plastic by spraying or yawing. The cover serves as protection against mechanical damage from outside and against penetration from moisture or, in the case of wet electrolytic capacitors, against the escape of the electrolyte. The envelope is therefore provided instead of a metal gel housing.

Capacitors for higher voltages, for pulse loads or Higher outputs are usually built into metal housings and are treated with a suitable impregnating agent, e.g. mineral oils or GhIordiphenyl etc. soaked in order to remove air inclusions and thus avoiding the use of the glow discharge or shifting it to higher voltages. In different In some cases, the impregnating agents should have certain chemical compositions that are suitable for the breakdown in the capacitor winding Release substances that are supposed to form non-conductive compounds with the reaction products that occur during the breakdown.

The present invention is concerned with the object of reducing manufacturing costs of power capacitors, if possible while maintaining the electrical values, and is expensive Saving primary process steps. According to the invention this is done by the combination of the following features is achieved:

a) the capacitor linings are made of vapor-deposited aluminum;

b) several capacitor windings are spaced apart

arranged in a row and closed with a plastic cover which shrinks during or after the Uriliüllungsprozeö encapsulated or overmolded in a structural unit.

709850/0235

A two-component product is expediently used as the plastic such as polyurethanes, epoxy resins or polyester resins. Polypropylene is advantageously used for the insulating film, which is preferably vapor-coated on one side with aluminum as a capacitor coating.

So far it was of the opinion that for the production of capacitors for higher voltages and powers, an impregnating agent was used cannot be dispensed with and in addition no vapor-deposited layers can be used. Surprisingly it has However, it has been found that this is possible if an appropriate pressure is exerted on the roll and that it is sufficient for this to use a suitable one during curing a permanent pressure on the capacitor coil to encapsulate or encapsulate producing plastic. To the Production of capacitors of greater power and higher voltage are, in a known manner, several according to the invention Capacitors connected in parallel and / or in series. This means that a single v / ikkel size can be used for all capacitor types produce and build this alone according to the invention or if necessary, several non-encapsulated or encapsulated capacitor windings can be cast together to form a capacitor module and use these modules as the basis for all required capacitor sizes. This gives you a dry, out plastic-encapsulated coils built up power capacitor, with the single elements or modules in simple Vfoise as standard manufactured, stored for any length of time and, if necessary, assembled into capacitors of the desired power and voltage and can be switched. Other advantageous details of the invention are described below with reference to the exemplary embodiments shown in the drawing.

Pig. 1 shows a capacitor according to the invention from the side in section,

Pig. 2 the structure of the individual layers, Pig. 3 a capacitor module according to the invention in one Top view,

Pig. 4 the module from the side in section, Pig. 5 one made up of several modules according to the invention Power capacitor in a common housing of the page in the cut,

fÖ9850 / 023 $

- ■ 'i' ·. G "oir ^ t the section of the circle of the pig. 5, i''- ;. 7 'is a S ji-old ^{scheme for phase alternating current, - · 1;} > β unci j Jo a switching scheme for rotary currents.

In Ii ¹ If; .-. 1 it't ait L denotes a condenser winding made of metal-coated,: in; 5bi.'s.) N: lf: i ':'nr.fcnllbs-'lanipften wound on a -.Vick ^ l ^ ohlriorn 2 There is insulating foils, the length v / echneli'eine projecting up to an end face or endon beforehand, as shown in enlarged form in FIG. The one final top capacitor plate J, which is applied on the Isolierstoffi'olie ^l v, iut by a sprayed or runs epreßte contact layer 5 contacts and provided with a connection part c. The overhang 7 of the insulating film S extends to the lower end face, is contacted there by an applied contact layer 9 and is provided with a connection conductor 10, which leads through the hollow winding mandrel 2 to the upper end face and projects beyond it.

urfinauri [j3._ ^¥ ; emä.o the coil 1 is not impregnated and encapsulated or overmolded with an ivoplastic envelope L1, a plastic being used which exerts pressure on the capacitor winding 1 after hardening and / or cooling. For the plastic sheath, compounds are preferably used which have a high temperature resistance, a favorable coefficient of thermal conductivity, high dielectric strength and low dielectric losses, so that a high voltage resistance and glow threshold voltage are guaranteed. These are preferably the reaction product of the mixture of two components or thermosetting plastics. A polyurethane is advantageously used to generate a moderate pressure, an epoxy resin is expediently used to generate a medium pressure, and a polyester resin is preferably used to generate a strong pressure. Mixtures of the individual abovementioned compositions are also possible. Furthermore, substances can expediently be added which ensure good heat conduction, but at least not significantly impair the other properties, for example aluminum oxide or magnesium oxide powder or particles of suitable size and shape.

üin according to the invention to a larger unit of several encapsulated capacitor windings is a combined module shown in Figures 3 and 4. Here are several capacitor windings 1 of e.g. about 1 kVAR and 400 V alternating voltage in each

709850/0235

Distance from each other in a row next to each other and optionally several such rows at a distance one behind the other to one Module assembled and together with a plastic cover 11 provided.

In the embodiment, three rows are arranged in one level and their upper and lower front sides are each connected to a busbar 12, 13, I ⁷ I-, 15, 16, 17, so that six connections, for example with U, Y, V /, X, Y, Z are designated, are present.

In each case in the plastic core between four adjacent capacitor windings 1 is a through hole 18 or an opening is provided through which the lower connections, here X, Y, Z are led out upwards.

The bores 18 serve at the same time for better heat dissipation and for better pressure distribution through the plastic casing 11 pressure exerted on the winding 1. In addition, they can be used to connect several modules by means of a Fastening element 24, e.g., a rod, together to connect, e.g. to screw and / or to fix the module on a carrier or in a container. By stacking multiple such modules and the respective connection of the same connections, a capacitor of higher power can be obtained. The Fir. 5 ·

In this embodiment of the invention there are six Modules according to FIGS. 3 and 4 with the interposition of spacers 19 stacked on top of each other and all connections X, all Y etc. together and up through bushings 20 from the housing cover 21 of a housing 22 led out. The spacers 19 advantageously consist of spacer rings that are placed over the bores 18 and can rest on their edge (cf. detail of FIG. 5). Advantageously intervenes tapered part 23 in the bores 18 a.

There are then connection options in the Di-Supervision 7 for single-phase alternating current, according to FIG. 8 for the Delta connection for three-phase current and remäi Fig. 9 for the star connection with three-phase current, as it is also used for clipboards. Motors and transformers are known.

TO9850 / Ö23®

To increase the operating voltage, the junction of one module can be connected to the input of the following module when the rioculn are superimposed. The container 22, which can be made of metal or l'unnt'rtjfi ', can advantageously be filled with a liquid, vorzur.Eueein, which enables the heat dissipated in the modules to be dissipated well. For this, however, a high-quality impregnating agent does not need to be used, as is the case with the previously customary impregnated Koncensatorarickeln, since this is not so heavily stressed here.

By using such plastic blocks with cast Capacitor windings can therefore be used in a wide variety of ways with one and the same type Power capacitors are manufactured. The former can therefore be manufactured and stored as a series product and, depending on the order, the appropriate capacitor type can be created in the shortest possible time, as there are no vacuum processes and impregnations more are required.

It has proven to be particularly favorable to use polypropylene foils that are vapor-coated with aluminum on one side as insulating foils and capacitor linings to before Vi end. Capacitors made from this material without impregnating agents are known and are used for motor and lamp capacitors, i.e. for voltages up to about 400 V AC, used. These capacitors cannot hold higher voltages, in particular the necessary test voltage of over 1000 V the end. However, it has been shown that when using an external Pressure on the coil, a test voltage of well over 1000 V can be achieved.

The glow start voltage increases with the pressure under which the not completely avoidable thin air layers are between the plastic films due to the shrinkage pressure of the plastic housing (plastic casing). The middle free It is known that the path length of the ionized gas molecules decreases with pressure, so that impact ionization becomes less likely. In comparison with the previous power capacitors, the glow current of the MKP lap under compression appears to be to have different meaning and valuation. While with the impregnated metal foil power constants the

709850/023 «

j ^ -

Glow current from a few weak points in the system, e.g. mainly from xiandzorien with increased field strength, from defects in the dielectric (plastic film, paper film) or on ketallic edges The test results indicate a metallic foil surface with the described MLP-V / ickeln on a more even, larger 'Glinmstroni. In other words, during the Glimiiistroii ;. in the case of the impregnated foil condensers of a few, locally narrowly limited places are disgusting large in MvP-V / i Areas involved. As for damage to the dielectric (foil) the current density is decisive, an equally large Glimnistrom can with an impregnated metal foil capacitor to damage lead, while the HKP-Wiekel shows no damage. This means that power capacitors and the individual windings can also be created with the cheap non-impregnated capacitor or modules can continue to function as hot and light condensers as before used because they are not more expensive in terms of price, but due to large-scale production for use in power capacitors and due to the possibility of being able to dispense with the previously required metal cup, ger; ebenenfallc get even cheaper.

an advantageous development of the invention can be any ar Individual capacitor winding 1 expediently in the area of the upper end face be equipped with a fuse, üs has namely surprisingly found that an inventive Capacitor despite the use of self-healing vapor-deposited Iletallbelägo and polypropylene as a carrier through the encapsulation respond to fuses with plastic. This experimentally observed behavior can be due to higher Energy conversion in a high pressure IIKP coil be explained. In fact, the penetration channels are much wider here observed than, for example, with the usual MP-WickeIn. This associated significantly greater energy consumption is expressed in an external current that a fuse respond can leave.

Due to the good properties of the capacitors according to the invention, like no risk of explosion, incombustibility, no leakage of impregnation liquid, it can be beneficial together with others Switching and Hegel devices, such as an electronic reactive power controller, special air contactors and the capacitors

TO9850 / 023B

Αβ

upstream Ιίΐί-Sicaerimren in a common fc>: "- holding cabinet be housed.

709850/0238

-44-

Blank page

Claims (21)

Patent claims: Electrical, non-impregnated, plastic-coated capacitor, its capacitor winding from one side ffiotallbedampftert Isolierstoffolien consists, characterized by the combination following Herkraale: a) the capacitor plates consist of steamed-up G.ii Aluminum, b) several Londeneatorwickel are at a distance from each other arranged in a height and with one leg: or after the wrapping process, shrinking plastic wrapping encapsulated or overmolded to form a structural unit. 2. Capacitor according to claim 1, characterized in that the insulating films consist of polypropylene. 3. Capacitor according to claim 1 or 2, characterized in that several cables are cast into a module. M-. Capacitor according to Claim 1, 2 or 3, characterized in that in a module containing several capacitor windings (1) between the capacitor windings (1) the plastic (11) is provided with continuous bores (18) running parallel to the capacitor windings (1). 5- capacitor according to at least one of claims 1 to 4, characterized in that the capacitor windings (l) are provided with a contact layer (5; 9) on the end faces, with the capacitor windings (l) of a module arranged in series, the lower ones in each case Contact layers (9) and the upper contact layers (5) of a row are connected to one another by a respective busbar (13 or 12; 15 or 14; 17 or 16). 6. Capacitor according to at least one of claims 1 to 5j, characterized in that each busbar (12 to 17) has a connection (U; ¥; V /; X; Y; Z). 7. Capacitor according to at least one of claims 1 to 6, characterized in that the or a rope of the bores (18) are used to implement the connections (U, V, W, X, Y, Z). 8. Capacitor according to at least one of claims 1 to 7> characterized in that the connections are in two rows of 709850/023 $ ORIGINAL INSPECTED Bores are provided so that in a row all inputs (U, V, V /) and all outputs (X, T, Z) are in the other. 9. Capacitor according to claim 8, characterized in that the connections of one row have the inputs in the order I, II, III, (U, V. W) and in the other the outputs in the order III, I, II (Z , X, X) are arranged. 10. Capacitor according to at least one of claims 1 to 9 » characterized in that several modules are arranged one above the other at a distance from one another with the interposition of spacers (19). 11. Capacitor according to at least one of claims 1 to 9> characterized in that the spacers (19) are provided in the region of the bores (18). 12. Capacitor according to claim 9 or 10, characterized in that there are provided annular spacers (19) around the bores (18). 13. Capacitor according to claim 12, characterized in that the ring-shaped spacer (19) has an extension (23) on at least one side which engages in a bore (18). 14. Capacitor according to at least one of claims 1 to 13, characterized in that a fastening element (24) engages through at least one bore (18). 15 · Capacitor according to claim 14, characterized in that the fastening element (24) is used to fasten one or the modules to a carrier or housing (22) and / or to hold several modules together. 16. Capacitor according to at least one of claims 1 to 15> characterized in that the connections (U, Y, W, I, Y, Z) are used to hold several modules together. 17. Capacitor according to at least one of claims 1 to 16, characterized in that one or more modules are accommodated in a housing (22) and the housing is filled with $ d.nem Iaoliermittel. 18. Capacitor according to claim 17, characterized in that 709850/0231 a. liquid isolating agent provided int 19 · Capacitor according to at least one of Claims 1 to 18, characterized in that each individual capacitor winding (1) is protected by a fuse 3t. 20. Capacitor according to claim 19, characterized in that: ä the fuse is provided in the area of the upper end face. 21. Capacitor according to at least one of claims 1 to 20, characterized in that it is housed in a common switch cabinet together with an electronic reactive power regulator, air contactors and upstream NH fuses.