EP0192915A1 - Transformateur avec rapport de transformation variable pendant le fonctionnement - Google Patents

Transformateur avec rapport de transformation variable pendant le fonctionnement Download PDF

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Publication number
EP0192915A1
EP0192915A1 EP85830050A EP85830050A EP0192915A1 EP 0192915 A1 EP0192915 A1 EP 0192915A1 EP 85830050 A EP85830050 A EP 85830050A EP 85830050 A EP85830050 A EP 85830050A EP 0192915 A1 EP0192915 A1 EP 0192915A1
Authority
EP
European Patent Office
Prior art keywords
wires
turn
winding
transformer according
core
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.)
Withdrawn
Application number
EP85830050A
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German (de)
English (en)
Inventor
Giovannini Secondo
Giovannini Gianni
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.)
Imec SpA
Original Assignee
Imec SpA
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Imec SpA filed Critical Imec SpA
Priority to EP85830050A priority Critical patent/EP0192915A1/fr
Publication of EP0192915A1 publication Critical patent/EP0192915A1/fr
Withdrawn legal-status Critical Current

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Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F29/00—Variable transformers or inductances not covered by group H01F21/00
    • H01F29/06—Variable transformers or inductances not covered by group H01F21/00 with current collector gliding or rolling on or along winding

Definitions

  • the present invention refers to a transformer, as well as an autotransformer with a turn ratio which can be varied (Variao) while in operation, designed to deliver a great power to an electric load with an adjustable voltage.
  • the main drawback originates from the fact that, in order to avoid the sudden short-circuit between two contiguous turns, a carbon brush is utilized for the picking-up of the current. Since the carbon has a quite high resistivity, the use thereof on the one hand limits the internal circulation current due to the short-circuit of the turn, but on the other hand it overheats in a geometripal proportion with respect to the magnitude of the current going through it.
  • variable turn ratio transformers in favour of the electronic regulation devices with silicon controlled diodes (SCR), which, however, although being able to drive strong currents, are very far from an ideal regula- ' tion of the voltage and current supplied to the load.
  • SCR devices produce a variable phase shift of the two components of the power, which implies, in certain operation conditions, the presence of very high amounts of apparent power.
  • one of the elements of a transformer is wound up as a twin wire winding and that the brush is caused to move on the winding so as it contacts at the most two contiguous turns, which must belong each to one of the two windings
  • object of the present invention is to overcome the above described drawbacks by means of a transformer, as well as an autotransformer which allows the overheating and the generation of electrical discharges to be avoided.
  • Another object of the present invention is to carry out such a transformer, as well as autotransformer in a simple and cheap way, suitable for mass production.
  • a transformer with a turn ratio variable while in operation is characterized in that at least two wires are wound together on the same core, are exactly interleaved and insulated with respect to each other, on them there is formed a collector free from insulation, on which a contact metal brush slides, and the ends of the wires are connected to each other, possibly through impedances, the arrangement being such that at every moment, during its movement, the brush touches every wire of the winding at the most at only one turn.
  • the internal circulation current flows in all the winding in opposite directions, generating in the self-inductances of the winding itself equal and discordant fluxes, counteracting against each other.
  • These self-inductances can then be increased, by enlarging the windings beyond the extremes of the part concerned with the motion of the brush.
  • the two wires have each the same voltage values as the other one.
  • the brush that picks up the voltage when shorts two contiguous turns, produces one of the two following effects: or a perfect parallel connection, when the two turns have the same potential, or an unbalanced parallel connection, in which an internal circulation current is produced, which is given by the ratio between the voltage of one turn and the impedance of the machine.
  • At least one turn of at least one wire of the winding is only partially linked with the total flux of the magnetic core of the transformer, by means of the use of at least another parted flux turn, the balancing of the voltage differences at the ends of the numerous wires being assured anyway, the arrangement being such that each wire of the collector has the same voltage difference with respect to each of the two contiguous wires.
  • two wires can be wound in parallel and the end turns of one of the wires of the winding, or the initial turn of. pne of the two wires and the final turn of the other one, can be linked with half of the total magnetic flux of the core.
  • the advantage is therefore achieved of being able to finely adjust the absolute amounts of the voltage and current, always keeping them in phase with each other, without there being practically any limitations to the power supplied to the load.
  • an autotransformer according to the present invention comprises a nagnetic core 10, on a column 12 of which there is a winding, sche- natically shown at 14, in which the machine current flows.
  • the winding 14 is provided with two posts 16 and 18, connected to the mains network, and is wound as a twin-wire winding.
  • the winding 14 is formed with two wires 20 and 22, which are carefully offset, exactly interleaved and insulated with respect to each other in the working area, and their ends are short-circuited with each other at the posts.
  • a metal brush 24, generally of copper, is connected to a load 26 and can move between two extremes 28 and 30 of the working area leaning at the most on two, never on three, contiguous wires.
  • a tap is provided on only one of the two wires, in this case the wire 22. To such a tap the other end of the load is connected.
  • Each of the two wires has to be sized for the nominal current of the transformer.
  • the internal circulation current due to the turn short-circuit which is found when the brush 24 shorts two contiguous turns, is therefore limited by the self-inductances formed at the ends of the winding and which are wound in the same direction, so that the mutual inductance also opposes the circulation of the turn shorts circuit current.
  • the winding 14 can be carried out with more than two parallel wires if the brush 14 has to be so large to short-circuit more than two contiguous wires.
  • the homonymous extremes of all the wires will be connected together, so that the winding results comprised of n wires all connected in parallel, the number n being computed so that at every moment, during its movement, the brush touches every wire at the most at only one turn.
  • a transformer according to the present invention differs from the autotransformer of figure 1 in that the two extremes 16 and 18 of the winding 14 are no longer connected to the mains network.
  • a primary winding is now wound, the extremes of which are connected to the network that supplies the electric power.
  • the voltage change can be carried out both at the secondary or primary winding; in this latter case, it is obvious that, by varying the supply, one varies the induction of the machine and consequently also the secondary voltage.
  • the other winding 22 conversely has its extreme turns with the wires threaded into the column 12 so as to embrace only half of the magnetic flux.
  • the number of the winding turns that embrace the whole flux is equal to the number of the turns of the winding 20 minus one, and this in order to keep the voltage and current balance between the two windings.
  • This principle of parting the flux linked with one turn can further be extended to enlarge as much as one likes the sharpness in the adjustment, by decreasing the voltage present between the contiguous wires in contact with the metal brush.
  • the internal circulation current can be controlled in a way different from that shown in the figure 1. There, the impedance of the extreme parts is utilized, leaving to the brush 24 the possibility of moving only on the central part of the two windings.
  • the extreme parts of the two windings can also be wound in a multilayer fashion and located under the central part, restraining in such a manner the longitudinal size of the column.
  • the zero voltage for the load is obtained.
  • an input impedance 40 is connected between the input posts 16 and 18 and the extremes 20a and 22a, on the one hand, and 20b and 22b, on the other hand, of the two windings 20 and 22, respectively.
  • the impedance 40 is comprised of two symmetrical windings 42 and 44. with central tap, to the ends of which the ends of the windings 20 and 22 are connected, and the central taps of which are connected to the input posts 16 and 18.
  • the impedance 40 must be sized for the power relating to half of a turn and furthermore the two windings 42 and 44 must be connected in such a manner that the internal circulation currents in the impedance are opposite in phase, as better shown in figure 4.
  • FIG 5 there is shown the use of an autotransformer according to the present invention for carrying out a voltage stabilizer.
  • the extreme 16 of the winding 14 and the brush 24 are connected to the two wires of the mains power, respectively, whereas the load 26 is connected between the same extreme 16 and an intermediate tap 46, provided on only one of the wires of the winding 14, in this case the wire 22.
  • the working area for the brush 24, going from 28 to 30, extends between about +10+15% and -10+15% of the nominal value of the mains voltage, nominal value at which the tap 46 for the load 26 has been carried out.
  • the moving of the brush can be carried out by a servo- mechanism connected to a drive system, besides well known to the skilled in the art.
  • the exactness of the voltage distribution in the machines carried out according to the present invention is such that it is possible to make equipotential connections of same voltage turns belonging to different transformers having equal structure and power and connected to the same phase, for instance in order to make a parallel connection of some machines to obtain high powers without increasing the turn voltage and therefore keeping the adjustment sharpness.
  • the ends of the wires which form the winding on which the brush operates can be connected by interposing impedances of any kind, such as inductances, resistances or capacitances, and combinations thereof. In this way it is possible to expand the part of the winding utilized as a working area, as besides already shown and described with reference to the figure 4.
  • cores of any shape can be used, e. g. annular cores.

Landscapes

  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Coils Of Transformers For General Uses (AREA)
EP85830050A 1985-02-27 1985-02-27 Transformateur avec rapport de transformation variable pendant le fonctionnement Withdrawn EP0192915A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
EP85830050A EP0192915A1 (fr) 1985-02-27 1985-02-27 Transformateur avec rapport de transformation variable pendant le fonctionnement

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
EP85830050A EP0192915A1 (fr) 1985-02-27 1985-02-27 Transformateur avec rapport de transformation variable pendant le fonctionnement

Publications (1)

Publication Number Publication Date
EP0192915A1 true EP0192915A1 (fr) 1986-09-03

Family

ID=8194673

Family Applications (1)

Application Number Title Priority Date Filing Date
EP85830050A Withdrawn EP0192915A1 (fr) 1985-02-27 1985-02-27 Transformateur avec rapport de transformation variable pendant le fonctionnement

Country Status (1)

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EP (1) EP0192915A1 (fr)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2008065112A1 (fr) * 2006-11-27 2008-06-05 Endress+Hauser Conducta Gesellschaft Für Mess- Und Regeltechnik Mbh+Co. Kg Détecteur inductif de conductivité

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE730390C (de) * 1937-08-22 1943-01-11 Aeg Anordnung zum Parallelbetrieb von feinstufigen Regeltransformatoren
DE1098603B (de) * 1957-01-23 1961-02-02 Wandler & Transformatorenwerk Regeltransformator
DE1281024B (de) * 1964-06-26 1969-03-27 Siemens Ag Stellwicklung mit Stromabnehmeeinrichtung fuer Transformatoren
US3461379A (en) * 1966-09-10 1969-08-12 Osaka Transformer Co Ltd Slide transformers and slide reactor devices
DE1638530B2 (de) * 1968-01-15 1974-03-07 Ruhstrat, Ernst Adolf, 3400 Goettingen Flachdrahtwicklung für einen Stelltransformator mit festen Wicklungen und Verfahren zur Herstellung der Flachdrahtwicklung

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE730390C (de) * 1937-08-22 1943-01-11 Aeg Anordnung zum Parallelbetrieb von feinstufigen Regeltransformatoren
DE1098603B (de) * 1957-01-23 1961-02-02 Wandler & Transformatorenwerk Regeltransformator
DE1281024B (de) * 1964-06-26 1969-03-27 Siemens Ag Stellwicklung mit Stromabnehmeeinrichtung fuer Transformatoren
US3461379A (en) * 1966-09-10 1969-08-12 Osaka Transformer Co Ltd Slide transformers and slide reactor devices
DE1638530B2 (de) * 1968-01-15 1974-03-07 Ruhstrat, Ernst Adolf, 3400 Goettingen Flachdrahtwicklung für einen Stelltransformator mit festen Wicklungen und Verfahren zur Herstellung der Flachdrahtwicklung

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2008065112A1 (fr) * 2006-11-27 2008-06-05 Endress+Hauser Conducta Gesellschaft Für Mess- Und Regeltechnik Mbh+Co. Kg Détecteur inductif de conductivité

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