US3766505A - Flyback transformer device - Google Patents

Flyback transformer device Download PDF

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Publication number
US3766505A
US3766505A US00174417A US3766505DA US3766505A US 3766505 A US3766505 A US 3766505A US 00174417 A US00174417 A US 00174417A US 3766505D A US3766505D A US 3766505DA US 3766505 A US3766505 A US 3766505A
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US
United States
Prior art keywords
flyback transformer
insulating oil
transformer device
oil
flyback
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US00174417A
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English (en)
Inventor
K Sato
S Shimazu
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Panasonic Holdings Corp
Original Assignee
Matsushita Electric Industrial Co Ltd
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Filing date
Publication date
Priority claimed from JP9096770U external-priority patent/JPS5139458Y1/ja
Application filed by Matsushita Electric Industrial Co Ltd filed Critical Matsushita Electric Industrial Co Ltd
Application granted granted Critical
Publication of US3766505A publication Critical patent/US3766505A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F27/00—Details of transformers or inductances, in general
    • H01F27/28—Coils; Windings; Conductive connections
    • H01F27/32—Insulating of coils, windings, or parts thereof
    • H01F27/321—Insulating of coils, windings, or parts thereof using a fluid for insulating purposes only
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F27/00—Details of transformers or inductances, in general
    • H01F27/02—Casings
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F38/00—Adaptations of transformers or inductances for specific applications or functions
    • H01F38/42—Flyback transformers

Definitions

  • ABSTRACT A flyback transformer device wherein a flyback transformer and diode are accommodated in a hermetically sealed metal container which is filled with insulating oil whose amount of charge resulting from corona discharge is less than a predetermined value.
  • FIG. 2 is a graph showing the relationship between the amount of charge resulting from corona discharge in insulating oil and the acceleration life time;
  • FIG. 3' is a sectional view of an apparatus for measuring the quantity of charge resulting from corona discharge in the insulating oil
  • FIG. 4 is a graph showing the relations of the accelerating 'life time to the dielectric loss of the insulating oil.
  • FIG. 5 is a sectional view showing the flyback transformer according to a second embodiment of this invention.
  • FIG. 1 of the drawings there is shown the basic construction of the flyback transformer device embodying the present invention, wherein numeral 1 represents a hermetically sealed metallic container in which is accommodated a transformer 2 which is adapted to produce a high-frequency high voltage upon being impressed with an input through a low-voltage terminal 3 from outside.
  • the high-frequency high voltage thus produced is rectified by a high-voltage diode 4 and then taken out through a high-voltage terminal 5 to be connected with a picture tube 6.
  • the space in the hermetically sealed container is entirely vacuum-impregnated with insulating oil as shown at 7 sothat no gas portion is present within the container.
  • the flyback transformer 2 comprises a core 2a, primary coil (primary winding) 2c, and high voltage coil'(secondary winding) 2b, the low-voltage and highvoltage terminals 3 and 5 including conductors 3a and St: for connecting the inside of the container to the outside respectively.
  • the distances for insulation between the various parts within the flyback transformer device can be reduced so that the device per se can be effectively miniaturized; however, at the conductor surfaces to which the high voltage flyback pulse is imparted, it is more likely that corona discharge occurs in the oil, and moreover the quantity of charge resulting from the corona discharge in the oil is very large as compared with the case of the conventional flyback transformer device designed such that the insulation space between the transformer and the metallic shield casing is large enough.
  • a reasonable and economical construction can be achieved by using insulating oil with a high corona discharge starting voltage and corona resistance in addition to taking the aforementioned countermeasures with respect to those portions where it is possible.
  • the determination of corona discharge starting voltage the high voltage charging portion is imperfect since it depends upon the sensitivity of means for detecting corona discharge, its electrode construction condition thereof and so forth. Therefore, the quantity of charge resulting from corona discharge is measured with such an electrode construction and applied voltage that an easily measurable degree of corona discharge occurs, and it has been found that there is a very close co-relation between the charge quantity thus measured and the result of an accelerated life test performed with a flyback transformer device using the same kind of insulating oil as in the present invention.
  • FIG. 2 is a graph showing the result, from which it will be seen that the life span changes sharply, with a corona discharge charge quantity of about 100 pico coulomb (pC) as the boundary, when a voltage of KVp (flyback pulse) is applied.
  • pC pico coulomb
  • FIG. 3 there is shown an electrode arrangement which is so .designed that the liability of occurrence of a corona andthe needle electrode 14 is connected with the high voltage flyback pulse of 15 KVp through a high voltage lead 15 and also with a device for measuring the quantity of charge stemming from corona discharge.
  • the needle electrode is so worked that the point end thereof has a radius of curvature of am.
  • dielectric loss occurs in an infinitesimal portion of the insulating oil to which a high frequency electric field is applied, and as it increases, the dielectric loss density (W/cm) in that portion is increased so that however small the aforementioned portion may be, this portion of the insulating oil is heated to a high temperature so as to be subject to thermal decomposition, evaporation, emission of dissolved gas or the like.
  • aninfinitesimal void is formed in the oil, which becomes a cause for corona discharge.
  • FIG. 4 shows the relationship between the dielectric loss of various types of insulating oil at 25C and the result of acceleration life tests performed in a manner similar to that described with reference to FIG. 2. From this, it will be noted that it is desirable that the dielectric loss of the insulating oil to be used be less than l X 10 in a frequency range of 10 2 X 10 Hz.
  • Noninflammability It is a well known and extensively adopted technique to use noninflammable oil of the diphenol chloride group as insulating oil with the view to improving apparatus with respect to safety; however, it has been seen from the foregoing that in the case of the flyback transformer according to this invention, it is inappropriate to employ such noninflammable insulating oil.
  • the flyback transformer device according to this invention there is no possibility that a short-circuit or a discharge accident tending to lead to fumingor combustion occurs which sometimes happens in the conventional dry type flyback transformer device impregnated with wax or the like.
  • Silicone liquid cannot be said to be non-inflammable itself; however, it has been found that in the case where it is used as insulating oil for the flyback transformer device according to this invention, silicone liquid is superior to certain kinds of non-inflammable insulating oil in that it is very stable, without fuming, with respect to external flame or the like. Thus, by using silicone liquid as insulating oil, the noninflammability of the flyback transformer device according to the present invention is greatly improved.
  • the specific inductive capacity of the insulating oil to be used has a value up to 4, it is possible to construct a flyback transformer device having satisfactory characteristics by correspondingly changing the numbers of turns of the coils, outer diameters of the windings and positional relationship between the primary coil (primary winding) and the high voltage coil (secondary winding), though the situation differs to some extent depending upon the spacing between the hermetically sealed container and the coil surfaces.
  • insulating oil having a specific inductive capacity greater than the aforementioned value it has been found that readily acceptable characteristics can be achieved by increasing the size of the sealed container, the coating thickness of the coil wire and so forth and by constructing the flyback transformer device as shown in FIG. 5. Description will now be made in connection with FIG.
  • numerals l to 7 indicate elements corresponding to those shown in FIG. 1 respectively
  • 8 denotes a spacer molded of a material having a low specific inductive capacity such for example as polypropylene or the like.
  • the spacer 8 is interposed between the sealed container 1 and the flyback transformer 2, serving to reduce stray capacitance which occurs therebetween and decrease the required quantity of the insulating oil to be used so as to reduce the extent of expansion and contraction of the oil which depends upon the temperature thereof.
  • the present flyback transformer device can be greatly miniaturized so that the bulk thereof can be made as small as about one-fifth of that of the conventional device.
  • silicone liquid is used as insulating oil
  • the thermal expansion coefficient of silicone liquid is about 10 percent higher than those of other kinds of insulating oil, it is also possible to decrease the amount of respiration which is required of the sealed metallic container to cope with temperature variations occurring in the flyback transformer device by reducing the quantity of the silicone liquid to be used.
  • a flyback transformer device comprising a hermetically sealed metallic container; a flyback transformer and a high voltage diode accommodated within said hermetically sealed metallic container, electric power being provided to said flyback transformer from outside said container to provide a high DC. voltage output by rectifying the high voltage pulses appearing in said flyback transformer; and insulating oil filling the entire space within said hermetically sealed metallic container including small gaps therein, said insulating oil being characterized by the quantity of charge stemming from a corona discharge occurring between a needle electrode and a flat electrode (the point end of said needle electrode has a radius of curvature of 20 um, and the spacing between said two electrodes is 5 mm) immersed in said oil being pico coulomb (pC) ofless when a flyback pulse of 15 KVp is applied to said electrode.
  • pC pico coulomb
  • a flyback transformer device wherein use is made of insulating oil of which the dielectric loss is less than 1 X 10 at 25C in a frequency range of 10" to 2 X 10 Hz.
  • a flyback transformer device according to claim 1, wherein said insulating oil, use is made of silicone liquid.

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Coils Or Transformers For Communication (AREA)
  • Organic Insulating Materials (AREA)
  • Details Of Television Scanning (AREA)
US00174417A 1970-08-27 1971-08-24 Flyback transformer device Expired - Lifetime US3766505A (en)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
JP7533670 1970-08-27
JP7533870 1970-08-27
JP9096770U JPS5139458Y1 (OSRAM) 1970-09-11 1970-09-11

Publications (1)

Publication Number Publication Date
US3766505A true US3766505A (en) 1973-10-16

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ID=27301780

Family Applications (1)

Application Number Title Priority Date Filing Date
US00174417A Expired - Lifetime US3766505A (en) 1970-08-27 1971-08-24 Flyback transformer device

Country Status (6)

Country Link
US (1) US3766505A (OSRAM)
BE (1) BE771793A (OSRAM)
DE (1) DE2142638C3 (OSRAM)
FR (1) FR2104881B1 (OSRAM)
GB (1) GB1353089A (OSRAM)
NL (1) NL159523B (OSRAM)

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3866086A (en) * 1972-06-28 1975-02-11 Matsushita Electric Industrial Co Ltd Flyback transformer apparatus
US3905001A (en) * 1972-10-31 1975-09-09 Matsushita Electric Industrial Co Ltd Oil-filled electrical instrument
US3904928A (en) * 1973-10-10 1975-09-09 Hitachi Ltd Flyback transformer
US5047744A (en) * 1990-01-23 1991-09-10 Plasma Technics, Inc. High voltage fluid filled transformer
US6188303B1 (en) * 1997-07-09 2001-02-13 Murata Manufacturing Co., Ltd. Flyback transformer
WO2008004107A3 (en) * 2006-07-03 2008-02-28 S E A Societa Elettromeccanica Power reactor for energy transfer

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
IT1046932B (it) * 1974-07-05 1980-07-31 Indesit Dispositivo per l ottenimento di una tensione continua extra elevata

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1905629A (en) * 1930-02-03 1933-04-25 Int Precipitation Co Apparatus for producing rectified high voltage electric current
US2478983A (en) * 1946-07-01 1949-08-16 Runbaken Julian Henry Electrical apparatus
US3234493A (en) * 1963-06-17 1966-02-08 Mc Graw Edison Co Distribution transformer having a molded insulative casing and oil dielectric
US3474369A (en) * 1967-12-05 1969-10-21 Allis Chalmers Mfg Co Hermetically sealed distribution transformer
US3521210A (en) * 1968-05-13 1970-07-21 Matsushita Electric Industrial Co Ltd Intermediate frequency transformer
US3546647A (en) * 1969-08-08 1970-12-08 Eltra Corp Electric coil construction
US3564386A (en) * 1968-12-27 1971-02-16 Westinghouse Electric Corp Power supply for converting high voltage alternating current into high voltage direct current

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CH331333A (de) * 1953-06-18 1958-07-15 Moser Glaser & Co Ag Elektrischer Hochspannungsapparat

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1905629A (en) * 1930-02-03 1933-04-25 Int Precipitation Co Apparatus for producing rectified high voltage electric current
US2478983A (en) * 1946-07-01 1949-08-16 Runbaken Julian Henry Electrical apparatus
US3234493A (en) * 1963-06-17 1966-02-08 Mc Graw Edison Co Distribution transformer having a molded insulative casing and oil dielectric
US3474369A (en) * 1967-12-05 1969-10-21 Allis Chalmers Mfg Co Hermetically sealed distribution transformer
US3521210A (en) * 1968-05-13 1970-07-21 Matsushita Electric Industrial Co Ltd Intermediate frequency transformer
US3564386A (en) * 1968-12-27 1971-02-16 Westinghouse Electric Corp Power supply for converting high voltage alternating current into high voltage direct current
US3546647A (en) * 1969-08-08 1970-12-08 Eltra Corp Electric coil construction

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
Ed. J. B. Birks; Modern Dielectric Materials, 1960, p. 146. *

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3866086A (en) * 1972-06-28 1975-02-11 Matsushita Electric Industrial Co Ltd Flyback transformer apparatus
US3905001A (en) * 1972-10-31 1975-09-09 Matsushita Electric Industrial Co Ltd Oil-filled electrical instrument
US3904928A (en) * 1973-10-10 1975-09-09 Hitachi Ltd Flyback transformer
US5047744A (en) * 1990-01-23 1991-09-10 Plasma Technics, Inc. High voltage fluid filled transformer
US6188303B1 (en) * 1997-07-09 2001-02-13 Murata Manufacturing Co., Ltd. Flyback transformer
US6524132B1 (en) 1997-07-09 2003-02-25 Murata Manufacturing Co., Ltd. Flyback transformer
WO2008004107A3 (en) * 2006-07-03 2008-02-28 S E A Societa Elettromeccanica Power reactor for energy transfer

Also Published As

Publication number Publication date
GB1353089A (en) 1974-05-15
FR2104881B1 (OSRAM) 1976-02-13
DE2142638C3 (de) 1973-12-20
DE2142638A1 (de) 1972-03-02
BE771793A (fr) 1971-12-31
DE2142638B2 (de) 1973-05-30
FR2104881A1 (OSRAM) 1972-04-21
NL7111750A (OSRAM) 1972-02-29
NL159523B (nl) 1979-02-15

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