US3844968A - New impregnation mixtures for electrical insulating mixtures - Google Patents

New impregnation mixtures for electrical insulating mixtures Download PDF

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Publication number
US3844968A
US3844968A US00223319A US22331972A US3844968A US 3844968 A US3844968 A US 3844968A US 00223319 A US00223319 A US 00223319A US 22331972 A US22331972 A US 22331972A US 3844968 A US3844968 A US 3844968A
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composition
weight
mixtures
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percent
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US00223319A
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P Jay
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Rhone Progil SA
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Rhone Progil SA
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Classifications

    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01GCAPACITORS; CAPACITORS, RECTIFIERS, DETECTORS, SWITCHING DEVICES, LIGHT-SENSITIVE OR TEMPERATURE-SENSITIVE DEVICES OF THE ELECTROLYTIC TYPE
    • H01G4/00Fixed capacitors; Processes of their manufacture
    • H01G4/002Details
    • H01G4/018Dielectrics
    • H01G4/20Dielectrics using combinations of dielectrics from more than one of groups H01G4/02 - H01G4/06
    • H01G4/22Dielectrics using combinations of dielectrics from more than one of groups H01G4/02 - H01G4/06 impregnated
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01BCABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
    • H01B3/00Insulators or insulating bodies characterised by the insulating materials; Selection of materials for their insulating or dielectric properties
    • H01B3/18Insulators or insulating bodies characterised by the insulating materials; Selection of materials for their insulating or dielectric properties mainly consisting of organic substances
    • H01B3/20Insulators or insulating bodies characterised by the insulating materials; Selection of materials for their insulating or dielectric properties mainly consisting of organic substances liquids, e.g. oils
    • H01B3/24Insulators or insulating bodies characterised by the insulating materials; Selection of materials for their insulating or dielectric properties mainly consisting of organic substances liquids, e.g. oils containing halogen in the molecules, e.g. halogenated oils
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01GCAPACITORS; CAPACITORS, RECTIFIERS, DETECTORS, SWITCHING DEVICES, LIGHT-SENSITIVE OR TEMPERATURE-SENSITIVE DEVICES OF THE ELECTROLYTIC TYPE
    • H01G4/00Fixed capacitors; Processes of their manufacture
    • H01G4/002Details
    • H01G4/018Dielectrics
    • H01G4/20Dielectrics using combinations of dielectrics from more than one of groups H01G4/02 - H01G4/06
    • H01G4/22Dielectrics using combinations of dielectrics from more than one of groups H01G4/02 - H01G4/06 impregnated
    • H01G4/221Dielectrics using combinations of dielectrics from more than one of groups H01G4/02 - H01G4/06 impregnated characterised by the composition of the impregnant
    • H01G4/222Dielectrics using combinations of dielectrics from more than one of groups H01G4/02 - H01G4/06 impregnated characterised by the composition of the impregnant halogenated

Definitions

  • ABSTRACT Dielectric liquids consisting essentially of a mixture of 25 33 parts of monochlorinated diphenyl, 28 36 parts of 2,4'-dichlor0diphenyl and 37 43 parts by weight of trichlorodiphenyl.
  • dichlorodiphenyl fractions and trichlorodiphenyl fractions are particularly interesting because of their high permittivity.
  • the tetrato hexachlorinated homologs have reduced dielectric constant values, such values decreasing as the number of chlorine atoms linked to the diph'enyl molecule increases; however, these higher chlorinated homologs do have. sufficiently high dielectric constant values for such products to find application as dielectric impregnants, particularly in admixture with the lower chlorine containing homologs.
  • the polychlorinated diphenyls in general possess a number of advantages in this field, one of the prime such advantages being great chemical stability.
  • dichlorodiphenyls for example, are crystallizable which prevents their use in electrical devices operating at low temperature.
  • Trichlorodiphenyls and the higher chlorine containing homologs do not crystallize, but they are considerably more viscous than the dichlorinatetl diphenyls which provides serious problems in attempting to impregnate the dielectric spacers, particularly when such spacers are not easily wettable.
  • metallized-paper capacitors and polyolefin film capacitors have several advantages over capacitors of the classical type made with paper.
  • the polyolefin film capacitors have a very high dielectric strength, but the polyolefin films are not easily wettable with the usual impregnating liquids, such as trichlorodiphenyl. and as a result have not in general been satisfactory because they do not wet sufficiently and the dielectric does not penetrate.
  • French Patent No. l,502,22l Nov. 18, I966
  • trichlorodiphenyl as an impregnating liquid for solid polyolefin spacers, but as pointed out above, this is not satisfactory.
  • dielectric liquids consisting of a mixture of polychlorinated diphenyls and trichlorobenzenes have a low viscosity and a low freezing point.
  • such mixtures have a much less satisfactory stability than do chlorodiphenyls, and, moreover, such mixtures have the disadvantage of having a high vapor pressure.
  • compositions which are applicable in a general way to usage in all insulated electrical devices, have shown'particular usefulness in the impregnation of dielectric materials which are normally very difficult to wet, such as polyolefin materials, and those which are used in low temperature environments.
  • the new dielectric liquid compositions consist essentially of a mixture of various diphenyl chlorination products in specified proportions, namely for parts by weight, from 25 33 parts of monochlorodiphenyl, from 28 36 parts by weight of 2,4-dichlorodiphenyl, and from 37 43 parts by weight of trichlorodiphenyl.
  • the present invention has a number of surprising aspects, one of which is that the monochlorodiphenyl product may be used in the substantial quantities indicated and that it not only does not detract from the properties of the composition, but adds to such proper ties.
  • the monochlorodiphenyl homolog was not satisfactory as a capacitor impregnant. Since this material is crystallizable, it could not be expected that one could use substantial quantities'of this material and obtain a liquid which would not crystallize.
  • other workers have tried to utilize mixtures containing this compound, noting for example French Patent No. 702,497 (Sept.
  • the monochlorodiphenyl to be used in accordance with the present invention may be any chlorinated diphenyl product, the chlorine content of which is at or near 1 chlorine atom per diphenyl molecule, and having only been subjected to a distillation to remove any tar. In other words, it is not necessary to utilize a pure isomer or to provide the monochlorodiphenyl in purified form.
  • the 2,4-dichlorodiphenyl fraction it is to be understood that any chlorinated diphenyl fraction, the total chlorine content of which corresponds to a proportion of about 2 chlorine atoms per diphenyl molecule, and in which the 2,4-isomer is present in a quantity of at least 50 percent by weight, is satisfactory.
  • the use of a pure 2,4-dichlorodiphenyl is not excluded from the present invention, it is preferred that the 2,4-dichlorodiphenyl fraction utilized in the present invention constitute in fact 65 85 percent by weight of the 2,4 isomer rather than 100 percent thereof.
  • a diphenyl chlorination product distilling between 154 164C.
  • the trichlorodiphenyl component used in the present invention has a chlorine content at or near 3 chlorine atoms per diphenyl molecule, i.e., it contains approximately 41 percent chlorine and has been treated to the extent that the chlorination tars have been removed as in the case of the monochlorodiphenyls discussed above. This is the same trichlorodiphenyl used in the prior art for impregnation of capacitors. Processes for obtaining this material are also found in Pat. No. 3,194,766.
  • the new dielectric impregnating liquids are provided in a single mixture, at room temperature, consisting essentially of the three constituents in suitable proportions; the liquids are preferably treated in accordance with the classical activated earth treatment.
  • the viscosity of the composition is lower than the classical trichlorodiphenyl impregnating liquid and, in general, if this characteristic is considered in relation to temperature it may be said that the viscosity of the mixture according to the present invention is similar to the viscosity of trichlorodiphenyl taken at a temperature higher than the temperature of the mixture in accordance with the present invention. This reduced viscosity is an important advantage.
  • Another surprising advantage of the present composition is its wetting power. There was no reason to predict that the wetting power of the composition would be better than the wetting power of the components, yet with regard to solid dielectric materials, particularly polyolefin films, it has been surprisingly found that the wetting power of the present composition is far superior to that of trichlorodiphenyl.
  • This wetting power may be evaluated by measuring contact angle of a liquid drop with a polyolefin film on which the drop is deposited; this is the angle between the surface of the film and the tangent to the curve of the drop at the contact point of the drop at the film. lt has been observed that for the mixture in accordance with the present invention, this angle is 39, while it is 48 for a drop of trichlorodiphenyl.
  • the liquid to be tested was poured into the tube and the temperature was brought to C. by means of an electrical resistance followed by stirring to obtain a good uniform temperature.
  • the liquid was thus maintained at 100C. for 2 hours and then the temperature was gradually increased 10 at a time over each subsequent 2 hour period, with the results being tabulated below at each temperature increment.
  • the test was conducted under identical conditions for the two liquid impregnants, namely the impregnant in the composition of the present invention and trichlorodiphenyl.
  • the impregnant of the present invention there was used a mixture of 27 percent monochlorodiphenyl, 36 percent dichlorodiphenyl with 60 percent of the 2,4 isomer, and 37 percent trichlorodiphenyl.
  • the weight of liquid recovered in the lower receptacle, at the end of each temperature increment, constitutes the measure of liquid penetrating power through the polypropylene film.
  • composition of the present invention has greatly superior penetrating power with regard to polyolefin film.
  • the dielectric properties of the impregnant of the present invention are very satisfactory.
  • the permittivity of these impregnants at 20C. is very near 6 and their dielectric losses are low.
  • a mixture according to the invention, with a density of 1.29 and a viscosity of 1.6 centistokes at 100C. has a loss angle (tg5), measured at 100C. and under 50 Hertz, of 0.005.
  • the dielectric liquids are intended to be used to impregnate polyolefin film capacitors, it may be advantageous to add with them a low quantity of a silicone oil, soluble therein, which results in the decreasing of the surface tension of the mixture and improves wetting even further.
  • a silicone oil soluble therein, which results in the decreasing of the surface tension of the mixture and improves wetting even further.
  • the selection of any particular silicone oil is not critical and, in general, one may choose any known product from the thinnest to the most viscous, provided that this silicone oil is entirely soluble in the mixtures according to the present invention in the. designated proportions.
  • polymethylphenyl siloxanes are particularly suitable and among'these compounds it is preferred to select those having a sufficiently low vapor pressure so that they are not removed by vaporization during the dielectric liquid degassing which takes place before impregnating the capacitors.
  • the quantity of silicone oil which may be added is also not particularly critical, except that the maximum quantity must not be so great that the silicone oil will be in effect a diluent; in a general way, the quantity of silicone oil used will generally be between 20 and 2,000 parts per million (ppm) with regard to the polychlorodiphenyl mixture. Based on tests conducted on mixtures according to the present invention and with added parts of silicone oil, the contact angle defined above was reduced to 25, 23, and 16 for silicone quantities added to the impregnant compositions of respectively 200, 500, 1,000 and 2,000 ppm.
  • these may be materials which combine with degradation products of the chlorinated diphenyls, under the action of electrical field; for example, hydrochloric acid may result from the degradation under electrical field of the chlorinated diphenylcompounds and the purifier adjuvants, often referred to as scavengers, are capable of reacting with the hydrochloric acid and thereby obviating its potential damaging effects.
  • purifiers or scavengers may be mentioned amines, morpholine derivatives, antimony and tin organic compounds and epoxide compounds.
  • Such epoxide compounds are particularly advantageous, particularly phenoxy-propylene, styrene oxide, diphenyl-ethylene oxide, epoxyethyl-l-epoxy- 3,4-cyclohexane, etc.
  • These additives may be incorporated without any disadvantage in mixtures according to the present invention and normal proportions, i.e., in quantities between 0.1 and 5 percent by weight with regard to the chlorinated diphenyl mixture.
  • liquid dielectric mixtures of the present invention have advantageous utility in all the normal applications of such liquids including, in a general way, electrical device insulation by means of impregnation. They are particularly useful in the treatment of materials subject to hard running conditions or materials which are difficult to impregnate with other liquid mixtures, such as for example, devices exposed at low temperatures, or capacitors having one or several polyolefin films which may or may not be used in conjunction with the conventional dielectric paper sheets.
  • the methods of treating the electrical devices with the liquids of the present invention are the same methods as are normally used with the chlorinated diphenyl materials.
  • the films may be impregnated with the dielectric liquid composition, such as by the use of vacuum, followed by heating for several hours at a temperature from 85 95C.
  • the impregnation may be achieved at a significantly lower temperature than that which has been utilizable in the past; for example, one may impregnate the capacitor using the composition of the present invention at only 60C., and this is substantially less than the temperature which may be used if one is attempting to impregnate using a viscous liquid such as trichlorodiphenyl.
  • the quality of the resulting impregnated devices are, in a general way, better than the properties of the impregnated devices obtained with the impregnation liquids of the prior art.
  • the capacity, the insulating resistance, and the aging properties are more than adequate for the various dielectric requirements.
  • a dielectric liquid according to the present invention was prepared by mixing, at room temperature, the following products in the indicated proportions:
  • This mixture had a total chlorine content of 33%. Its viscosity was 16 centistokes at 20C.; 3.6 centistokes at 60C.; 1.6 centistoke at l0OC. lts permittivity was 6.0 at 20C. Cooled to --C., it did not crystallize, even after priming or seeding.
  • This mixture was used to impregnate a series of 10 capacitors. Those had aluminum frames separated by an insulating set composed of two polypropylene films 12 microns thick, placed on every side of a Kraft paper sheet for capacitors, having a thickness of IO microns. lmpregnation was made at C., under a pressure of 10' mm. Hg. after drying. Then the devices were maintained at 90C. for 4 hours under a normal pressure.
  • EXAMPLE 2 As a comparison, capacitors impregnated either with a liquid according to the invention, or with trichlorodiphenyl were submitted to a test of dielectric rigidity under continuous voltage.
  • a liquid composition for the impregnation of electrical insulating materials consisting substantially of a mixture of 25 33 parts by weight of monochlorodiphenyl, 28 36 parts by weight of dichlorodiphenyl consisting of at least 50 percent of the 2,4 isomer, and 37 43 parts by weight of trichlorodiphenyl.
  • dichlorodiphenyl is a diphenyl chlorination product distilling between 154 and l64C. under a pressure of 10 mm. Hg. and containing 75 percent by weight of 2,4'-dichlorodiphenyl.
  • composition in accordance with claim 1 further comprising 20 2,000 ppm based on said parts by weight of a silicone oil.
  • composition in accordance with claim 4 wherein said silicone oil is a methylphenylpolysiloxane.
  • composition in accordance with claim 1 further comprising 0.] 5 percent by weight based on said I00 parts of a hydrochloric acid scavenger.
  • composition in accordance with claim 6 wherein said scavenger is an epoxide compound.

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Physics & Mathematics (AREA)
  • Chemical & Material Sciences (AREA)
  • Oil, Petroleum & Natural Gas (AREA)
  • Spectroscopy & Molecular Physics (AREA)
  • Manufacturing & Machinery (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • Organic Insulating Materials (AREA)
  • Fixed Capacitors And Capacitor Manufacturing Machines (AREA)
US00223319A 1971-02-05 1972-02-03 New impregnation mixtures for electrical insulating mixtures Expired - Lifetime US3844968A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
FR7104692A FR2124184B1 (fr) 1971-02-05 1971-02-05

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US3844968A true US3844968A (en) 1974-10-29

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US (1) US3844968A (fr)
AU (1) AU458561B2 (fr)
BE (1) BE779009A (fr)
CA (1) CA971750A (fr)
DE (1) DE2202684C3 (fr)
ES (1) ES399490A1 (fr)
FR (1) FR2124184B1 (fr)
GB (1) GB1336266A (fr)
IT (1) IT948436B (fr)
SE (1) SE380657B (fr)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4097912A (en) * 1974-04-01 1978-06-27 Mcgraw-Edison Company Electrical capacitor having an impregnated dielectric
US4097913A (en) * 1975-01-20 1978-06-27 Mcgraw-Edison Company Electrical capacitor having an impregnated dielectric system
US4115834A (en) * 1976-08-23 1978-09-19 Cornell-Dubilier Electric Corp. Dielectric composition and device containing same
US4177156A (en) * 1977-03-10 1979-12-04 Rhone-Poulenc Industries Dielectric compositions comprising mixtures of polychlorinated benzenes and alkylaromatic hydrocarbons
US5014033A (en) * 1988-09-30 1991-05-07 Atochem Dielectric liquid compositions containing hydroxybenzaldehyde

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR702497A (fr) * 1929-10-28 1931-04-09 Fed Phosphorus Co Huile pour tranformateurs
US3038107A (en) * 1959-06-08 1962-06-05 Monsanto Chemicals Liquid dielectric compositions, method of preparation and use thereof
US3068297A (en) * 1961-04-21 1962-12-11 Monsanto Chemicals Isomerization of halobiphenyls
US3072728A (en) * 1960-03-24 1963-01-08 Monsanto Chemicals Method of preparing halogenated diphenyl compounds
US3194766A (en) * 1961-10-04 1965-07-13 Progil Dielectric composition

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
SE355689B (fr) * 1965-11-18 1973-04-30 Gen Electric

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR702497A (fr) * 1929-10-28 1931-04-09 Fed Phosphorus Co Huile pour tranformateurs
US3038107A (en) * 1959-06-08 1962-06-05 Monsanto Chemicals Liquid dielectric compositions, method of preparation and use thereof
US3072728A (en) * 1960-03-24 1963-01-08 Monsanto Chemicals Method of preparing halogenated diphenyl compounds
US3068297A (en) * 1961-04-21 1962-12-11 Monsanto Chemicals Isomerization of halobiphenyls
US3194766A (en) * 1961-10-04 1965-07-13 Progil Dielectric composition

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4097912A (en) * 1974-04-01 1978-06-27 Mcgraw-Edison Company Electrical capacitor having an impregnated dielectric
US4097913A (en) * 1975-01-20 1978-06-27 Mcgraw-Edison Company Electrical capacitor having an impregnated dielectric system
US4115834A (en) * 1976-08-23 1978-09-19 Cornell-Dubilier Electric Corp. Dielectric composition and device containing same
US4177156A (en) * 1977-03-10 1979-12-04 Rhone-Poulenc Industries Dielectric compositions comprising mixtures of polychlorinated benzenes and alkylaromatic hydrocarbons
US5014033A (en) * 1988-09-30 1991-05-07 Atochem Dielectric liquid compositions containing hydroxybenzaldehyde

Also Published As

Publication number Publication date
DE2202684B2 (de) 1973-11-08
CA971750A (en) 1975-07-29
AU3857472A (en) 1973-08-09
FR2124184A1 (fr) 1972-09-22
FR2124184B1 (fr) 1975-01-17
ES399490A1 (es) 1974-11-01
AU458561B2 (en) 1975-02-06
SE380657B (sv) 1975-11-10
BE779009A (fr) 1972-08-04
GB1336266A (en) 1973-11-07
DE2202684C3 (de) 1974-06-20
IT948436B (it) 1973-05-30
DE2202684A1 (de) 1972-08-24

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