Classifications

• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
  • H01F37/00—Fixed inductances not covered by group H01F17/00
• • 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
  • H01F27/24—Magnetic cores
  • H01F27/245—Magnetic cores made from sheets, e.g. grain-oriented
• • 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
  • H01F38/08—High-leakage transformers or inductances
  • H01F38/10—Ballasts, e.g. for discharge lamps

Definitions

• Reactors are used in discharge lamps such as e.g. fluorescent tubes, in which the reactors limit the lamp current through their inductive resistance.
• Th e present invention relates to a reactor for the above mentioned purpose, said reactor comprising a core provided with a coil.
• the core is made up of yokes and legs in such a manner that at least two openings are formed in the core.
• the yokes and the legs of the core are made up of laminations of plates.
• One air gap is arranged between one of the legs and a yoke.
• Reactors reactive coils of this kind are previously known per se. There are two important factors that have to be borne in mind when designing reactors for fluorescent tubes. The reactor must be inexpensive to manufacture and it must have a good operating economy, which means that its loss of power should be as small as possible. In the normally used reactors for 4 0Y fluorescent tubes the loss of power amounts to about9-12 %
• a further factor that influences the design of a reactor for fluorescent tubs is to see to that gaps in the construction do not create a leak flux. Such a leak flux might excite adjacent iron parts and put these parts in t o vibrations, which would cause a non-desirable noise.
• the core can be up of laminations of plates of ferro-magnetic material having a magnetic preference direction. This entails an essentially improved flux density, by what means the utilization factor of the reactor is improved.
• a low-losa reactor which comprises a core made up of standardized elements, that are cut from bands of rolled, directionally oriented plates (fig. 1).
• This reactor comprises two coils and the air. gap is divided into four gaps. In this way the leak flux is minimised and a low level of noise is obtained.
• Such a reactor entails a low loss of power, but the relatively large area of copper makes it expensive to manufacture, due to the high costs of copper.
• the core of this reactor is alsomade up of standardized elements of directionally oriented plates. There ia no waste when cutting the plates, since they are cut at an angle of49° in relationto the rolling direction for the plates.
• This reactor entails a low loss of power but. its composition is so complicated that the manufacture of it, becomes too expensive.
• At least one of the yokes is made up of laminations of plates of a non-directionally oriented kind, whereas the remaining yoke and legs in the core consist of lam ina tions of plates having a magnetic preference direction.
• the core of one embodiment of the invention comprises an upper and a lower yoke having intermediary legs wherein the two yokes are made up of laminations of non-directionally oriented plates.
• figs. 1-2 show examples of reactors having directionally oriented plates
• fig. 5 shows - partly in section - a perspective view of a preferred reactor, fig. A shows a schematic cross section of the preferred reactor.
• reactors having cores made up of directionally oriented plates.
• the embodiment according to fig. 1 comprises two coils b and four air gaps c.
• a reactor having the coil enclosed by directionally oriented plates a with air gaps c according to fig. 2 entails a reduced copper area and an increased iron area.
• the reactor 1 (figs. 3-4) comprises an iron core, which is composed of an upper yoke 2 and a lower yoke 3 having three intermediary legs 4a,4b,4c.
• the coil 5 of the reactor 1 is carried by the middle leg 4b.
• the air gap 6 is situated between the upper yoke 2 and said middle leg 4b.
• Each of the yokes 2,3 and the legs is made up of laminations of plates.
• the laminations in the legs 4a, 4b, 4c consist of plates of ferro-magnetic material having a magnetic preference direction.
• the yokes and the legs are connected in a not described mariner to a closed unit 1.
• the length of the coil 20 mm
• the resistance of the coil can now be calculated:
• the resistance and loss of power at 90oC is also calculated below:
• the laminations in the legs 4a, 4c have the dimensions 20 x 10 mm.
• the laminations in the middle leg 4b have the dimensions 19 x 10 mm.
• the laminations in the yokes 2,3 have the dimensions 50 x 10. mm.

Landscapes

• Engineering & Computer Science (AREA)
• Power Engineering (AREA)
• Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
• Physical Or Chemical Processes And Apparatus (AREA)
• Coils Of Transformers For General Uses (AREA)
• Electromagnets (AREA)

Applications Claiming Priority (2)

Publications (1)

Family

ID=20340412

Family Applications (1)

Country Status (8)

Families Citing this family (4)

Family Cites Families (1)

• 1980
  • 1980-03-04 SE SE8001690A patent/SE421844B/sv unknown
• 1981
  • 1981-03-02 JP JP56500804A patent/JPS57500222A/ja active Pending
  • 1981-03-02 EP EP81900547A patent/EP0047266A1/en not_active Withdrawn
  • 1981-03-02 GB GB8132096A patent/GB2083290B/en not_active Expired
  • 1981-03-02 WO PCT/SE1981/000056 patent/WO1981002648A1/en not_active Application Discontinuation
  • 1981-03-03 IT IT8120101A patent/IT8120101A0/it unknown
  • 1981-10-16 FI FI813245A patent/FI813245L/fi not_active Application Discontinuation
  • 1981-11-02 NO NO813702A patent/NO813702L/no unknown

Non-Patent Citations (1)

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