US2595024A - Contact arc suppression - Google Patents

Contact arc suppression Download PDF

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Publication number
US2595024A
US2595024A US70926A US7092649A US2595024A US 2595024 A US2595024 A US 2595024A US 70926 A US70926 A US 70926A US 7092649 A US7092649 A US 7092649A US 2595024 A US2595024 A US 2595024A
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current
voltage
circuit
rectifier
interrupting
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Expired - Lifetime
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US70926A
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English (en)
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Toulon Pierre Marie Gabriel
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Products & Licensing Corp
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Products & Licensing Corp
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
    • H01H9/00—Details of switching devices, not covered by groups H01H1/00 - H01H7/00
    • H01H9/54—Circuit arrangements not adapted to a particular application of the switching device and for which no provision exists elsewhere
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02K—DYNAMO-ELECTRIC MACHINES
    • H02K13/00—Structural associations of current collectors with motors or generators, e.g. brush mounting plates or connections to windings; Disposition of current collectors in motors or generators; Arrangements for improving commutation
    • H02K13/14—Circuit arrangements for improvement of commutation, e.g. by use of unidirectionally conductive elements

Definitions

  • the present invention relates to a new method and apparatus for breaking electrical circuits, which carry currents of a relatively high in tensity, without the resultant emissicn of sparks or arcs.
  • the invention relates more particuiariy to the separation of contacts through which flows a strong current, without initiation of an arc, such as usually asphalts between such contacts.
  • the invention is applicable more particularly to break switch systems for industrial currents at high voltage and current, as well as to all electrical machines which present the problem of commutation, and in which the invention would permit the suppression of sparks resulting therefrom.
  • a rectifier is inserted in series with the break switch in the first case, or with the commutation brush in the second case; and previous to the break, or to the commutation, an auxiliary voltage is introduced into the circuit (voltage which will be designated in the text as countervoltage), and in the opposite direction to the one which causes the current, and of an amplitude which would only need to be at least equal to it, but which may be greater.
  • the current is reduced in the circuit at the contacts which are to be separated, by making it pass progressively in a line shunted on this circuit:
  • the counter-vcltaga may be introduced either directly into the first circuit, or into the shunt, in reversing the polarity.
  • a variation of the invention consists of putting a rectifier in series with the switch, and of branching in parallel to this circuit a condenser in series with a coil into which has been introduced the countervoltage in question.
  • the eiect of this latter is to switch the current progressivcly from the switch towards the condenser, which is progressivcly charged and the switch is opened when the current in the contacts has completely stopped.
  • the effect of this is that the condenser continues to be charged, until it has balanced the voltage of the network.
  • the condenser employed must be consequently capable of handling the total voltage of the network, and it must on the other hand have great enough capacity to be able to absorb suificient charge.
  • T0 recluce the size of this capacity the operation of circuit opening may be executed in two steps, by twice following the procedure to which the invention relates.
  • Tvvo interrupters arranged in series one with the other are utilized. Th opening of the first interrupter brings about a primary' reduction of the current, by inserting a resistance in series. Afterwards the second interrupter is opened, thereby completely opening the circuit, in the same way as has been described in the variation mentioned above.
  • the arrangement consists therefore in introducing in series with the principal interrupter, an auxiliary circuit opening devise with a shunt in parallel,- which will have an appropriate resistance. In conformity with the procedure already described, all of the current is diverted into this shunt and the auxiliary interrupter is then opened. A resistance is thereby inserted into the circuit, the efiect of which is to reduce the current to a-small fraction of its original value.
  • the invention is applicable also to cases in which the break is due to an accidental cause, for example, a short circuit.
  • the invention provides in this case means, controlled by the abrupt increase in current, to introduce a circuit in shunt with a breaker switch, and to .SWitch the current into the latter, the resistance of the shunt preventing the current from acquiring dangerous proportions.
  • each brush ordinarily used is replaced by two rotary brushes which bear on the fixed segments, and which Will be coupled to the secondary of a transformer laid out in so many rows; and in series with each brush is connected a rectifier and a coil into which a voltage may be induced.
  • this Voltage is applied by means of a transformer whose secondary has its terminals connected to the brushes.
  • the brushes are driven by a motor, synchronized With the frequency of the network.
  • the shaft of this motor drives a small alternator which will furnish a frequency in synchronism with that of the network.
  • This Irequenoy is used to feed the primary of the auxiliary transformer.
  • the alternator may be either two-phase, in which case there is required only two rows of brushes, or poly-phase, for example hexaphase, in which case the steps are arranged on six independent rows regularly shifted with respect to one another.
  • Figure 1 illustrates an embodiment of the invention which employs a rectifier and an auxil iary voltage, to suppress current fiow at the moment et circuit opening.
  • Figure 2 represents, as a function of time, the currents and voltages in the diierent circuits of Fi ure 1.
  • FIG 3 illustrates a variant of the, system 01 Figure 1, in which two parallel circuits are employecl.
  • Figure 4 is a circuit diagram of a system for breaking current at high voltage, in accordance with the invention.
  • Figure 5 is a circuit diagram of a system for providing protection against short-circuits, in electrical systems, in accordance with the invention.
  • Figure 6 illustrates the application of the invention to a high tension commutator.
  • Figure 7 illustrates a perfected variant of the system of Figure 6, utilizing a polyphase commutation voltage.
  • Figure 8 illustrates on a greatly enl&rged scale, 2. portion of the r0Ws of brushes, showing et. ea ch 4 instant the relative position of the brushes in relation to the commutator segments.
  • FIG. 1 is a circuit diagram of a system which illustrates the principle of the new procedure to which the invention relates.
  • W may be a source of either continuons current. or of. variable current, provided however that the frequency of this current be relatively small in relationship to the speed of the phenomena occurring in the system.
  • This source fiows into a circuit presenting a resistance N and an inductance L.
  • the problem that 1 propose to solve is that 01 interrupting the current by means of an interrupter C (whose points 01 contact have been represented by semicircles in the drawing) without any sparks being produced at the moment of the interruption.
  • a rectifier R placed in series with the circuit, oriented in such et direction that it 1ets the current flow normally, and a device U (generally the secondary of a transformer) is introcluced in which one can momentarily cause to appear a tension X, thanks to an exterior device G (for example by throwing into the primary of the transformer U a variable current).
  • the current which circulates in the contactor C is annulled by generating, by means of the device G, a voltage U, which will be equal to or greater than E.
  • the first curve, 2a represents as a function of time, the voltage U.
  • the curve, 2b represents, in function of time, the voltage at the terminale of the rectifier R; the third curve, 2c, represents, as a function ci time, the current 2; and the fourth curve, 2:1, represents as a function of time, the voltage be tWeen the electrodes of the contacter C.
  • the generator G induces progressively in U a voltage, which, in conformity With the invention, exceecls the voltage E. In proportion as the voltage U increases, the current i is reduced progressively. If the voltage U is greater than W, the current 2' is annulled.
  • the rectifier assumes a voltage of reverse polarity, as shown on curve 2b. Thanks to the pres ence of the rectifier R, the current romains zero from T2. At any time whatsoever, for example, at the moment T3, one may separate the two points of contacts C without any sparks being produced.
  • the instant of the cutting off, 'I3, may be set anywhere in the interval XX, during which the voltage induced by G on U furnishes a voltage greater than W.
  • the invention solves therefore the problem of breaking current fiow, without sparks, the only condition being that the induced voltage generated in U be sufficiently high.
  • Figure 3 illustrates a variant of Figure 1, in which two circuits in parallel are employed. This system is particularly interesting when the input voltage W is very high and when one is trying to break the circuit without using too high tensions U.
  • the supply voltage W, the resistance N, the inductance L, in which circulates the current X 2 utilize two parallel branches, a first branch, U1, R, C, traversed by the current il, and a second branch U2, traversed by the current i2.
  • E the voltage across U1+R+C.
  • the generator G can induce either a voltage U1 et the opposite sign to E, in one of the parts branches of the circuit or a voltage U1, of the saine sign as E, in the other branch.
  • the voltage provided by generator G has the eifect of annulling the current 7:1, and of thereby permitting the separation of the contacts C without sparks or arcs resulting from the break.
  • Figure 4 illustrates in detail a system corresponding with the systems schematically illustrated in Figure 3, as applied to the interruption of a high voltage circuit.
  • I employ a source of continuous current Il, feeding, across a high resistance l0, a condenser 9.
  • the discharge of thecondenser 9 can, in the primary coil of transformer 6, be obtained at the moment desired, thanks to the switch 8.
  • T induce in the coil l4 a transient voltage
  • I employ a source Il, feeding, across a high resistance Il, a condenser 16.
  • the discharge of the condenser l6 in the primary winding of the transformer [4, may be initiated at the moment desired, by means of the device F2 contained in the block 8l.
  • This device comprises two electrodes l8 and [9, between which an arc may arise, and an electrod 20 placed in the vicinity of these two electrodes, and the potential of which controls release of the arc.
  • This potentia1 of the electrode 20 is modified by utilising a small auxiliary source 2l, a resistance, and a small auxiliary switch 22.
  • the relay spark gap shown in the block *8 is therefore of great interest, because it has no movable parts and it can operate in an extremely short time, and is not slowed by the mechanical inertia cf parts.
  • Figure 5 is a variation of Figure 4,'more ecpecially adapted to protection against short circuits. Crie finals again on this diagram the same principal elements (source W, load 2, contacts [3, rectifier l2; and a coii I in which is induced the voltage U, etc.)
  • the short circuit of the line is represented in the Iorm of switch 25, When this short circuit 15 produced, the generator W has a tendency to give out a much stronger current than th normal one. But, thanks to the self-induction 3 of the generator and of the line, this current increases progressively and relatively slowly.
  • Th relay 28 closes the switches 29 and 30.
  • the switch 30 has the effect of closing the circuit of the first transformer I4, the current in which annuls momentaneously the current in the contacts I3.
  • I utilize the discharge of a condenser H5, maintained at high voltage by a source Il, through a resistance Il.
  • the switch 29 closes the circuit of an auxiliary battery 31 and applies current to the C011 2! which actuates the mechanism 26, for opening contacts 13.
  • the separation of the contacts l3 is produced noticeably at the moment when the variation of current flow (due to the discharge current of the condenser l6) attains its maximum, that is to say at the moment when th voltage in the secondary M passes through its maximum.
  • the resistance 24 is chosen to have a value comparable to that of the resistance 2, in such a way that, in case of a short circuit, the current after having momentarily exceeded slightly the normal value corne progressively back to it aiter a fairly short time.
  • Figure 6 shows the application of the system of Figure 3 to a system of rectification cf alternating triphase current into a continuous current.
  • the triphase feeding current is supposed to excite a coil winding 31, in the form of a ring gramme immovable in space.
  • Rotary brushes driven by a little synchronous motor Will rub against this ring.
  • the wires of the primary power sources have not been shown, and the ring 8 nected respectively to the segments 34 and to the segments 35, arranged alternately on two coaxial rows.
  • the brushes 32 and 33 are supposed to turn at the speed of synchronism, by a mechanism which is not shown and which comprises a synchronous motor driven by a shaft coupled to the brushes.
  • This mechanism drives also a group of symmetrical brushes, not shown.
  • Only one brush 40 has been shown at the bottom of the drawing, in order to make clear how the circuit is closed, but it must be admitted evidently that the disposition of the circuits in the lower part of the drawing, is exactly analogous to that described above.
  • the voltage generated in the secondary windings Si and S2 has the eifect of annulling alternately the current of the brushes 32 and 33.
  • Figure 7 illustrates a variant of the system of Figure 6, but instead of using an arrangement, in form of a ring, I use simple monophase transformers, appropriately connected.
  • the system is applicable also to the case of a rectifier permitting the transformation of the energy of a triphase source il to a source of continuons currnt at high voltage 68.
  • I multiply the number of phases of the triphase distribution by means of a number of static transformers.
  • an alternator 63 furnishing a triphase voltage 84, the frequency of this alternator being equal to the product of the number of steps situated on each row by the number of rotations per second efiectuated by the frame 60.
  • I feed the primaries 85 and 85 of the two polyphased transformers.
  • the secondaries 86 and 86 are connected each in a 6 branched star, the neutral points of these stars connected to the terminals of the load.
  • Each of the phases of each of the secondaries feeds a rotary brush, across arectifier, such as 81 and 81.
  • the direction of this rectifier is established in such a fashion that the current can only circulate in it in the desired direction of the feeding of the load 10 circuit 68, when the system is used to feed this circuit with continuous current.
  • the rectifiers in liaison with the transformers 86 are sufiicient to assure sparkless commutation, as has already been described above.
  • the alternator 63 carries with it an excitation shunt field winding 86, but preferably, it has also an excitation series field winding 61, so that the voltage induced in the transformers and 85' augments a great deal with the charge, and this assures excellent commutation no matter what the charging regime: as a matter of tact, the voltage of self-induction induced in the windings during commutation increases with the charge, and it is therefore advisable to create an auxiliary commutation voltage, to assure the commutation without sparks, proportionately greater as the charge is greater.
  • Figure 8 represents, on a large scale, and in their respective positions, the sectors of the different rows il, I2, 13, 74, 15, 16 on which the 6 brushes 11, I8, 19, 80, al, 82, contact.
  • the current begins to circulate in one brush (such as 11) as soon as the voltage of commutation furnished to the brush surpasses that of the preceding brush and the brush ceases to pass current /6 period after.
  • the current in the brush 11 only increases slowly and when the electromotive force of selfinduction is equal to that of the voltage of commutation, one may observe in the intensity a level run. It is only when the current attains in the following brushes, a notable current that the current is progressively reduced, and it only stops slowly.
  • the commutation time is found to be considerably augmented, nevertheless, thanks to the new disposition, several brushes 2 or 3 for example, such as I1, I8, I9, can give current forth simultaneously. Because of this, for a machine of a given power the current in each brush is considerably reduced. Vice versa, for a given dimension of the brush, it is possible to design a much more powerful machine.
  • An electrical circuit interrupting system comprising a source of voltage, a load circuit, a pair of normally closed circuit making and breaking contacts, a rectifier poled to pass current in response to said voltage, means connecting in series said source of voltage, said load circuit, said contacts and said rectifier, means for temporarily impressing in opposition to said voltage an auxiliary voltage at least as great as said fi1st mentioned voltage, and means for thereaiter opening said contacts, whereby said contacts are opened during a condition of zero current flow in said load circuit.
  • a system for interrupting fiow of electric current in a high voltage circuit comprising, in combination: means for interrupting said circuit, means for generating a transient voltage having a polarity opposite to and in magnitude at least as great as said high voltage, means for impressing said transient voltage in said circuit, rectifier means connected in said circuit and poled to prevent reversal of Current fiow in response to said transient voltage, and means for actuating said means for interrupting during said transient voltage 3.
  • a system in accordance with claim 2 Wherein said transient voltage is connected in series With said means for interrupcing.
  • a system for interrupting the fiow of electrie current in a circuit at high voltage comprising, in ccmbination: means for interrupting said circuit, means for generating a transient voltage, said last means comprising a condenser and a primary winding of a transformer connected in series, a secondary winding coupled to said primary Winding, means connecting said secondary winding in said circuit, said transformer being adapted and arranged to induce into said secondary winding a transient voltage opposing said fiow of electric current in response to discharge of said condenser and of magnitude greater than said high voltage, rectifier means connected in said circuit and poled to prevent reversal of said electric current in response to said transient voltage, and means for actuating said means for interrupting during said transient voltage.
  • a system for interrupting fiow of electric current in a high voltage circuit comprising, in combination: first means for interrupting said circuit, second means for interrupting said circuit, said first and second means connected in series in said circuit, et resistive circuit shunting said first means for interrupting, means for reducing transiently t zero voltage existing across said first means for interrupting, means for actuating said first means for interrupting to interrupting condition during said zero voltage, said electric current then fiowing to said second means for interruptin via said resistive circuit, means for reducing current fiow in said circuit to zero for an interval of time, and means operative during said interval of time for actuating 12 said second means for interrupting to interrupting condition.
  • a system for interrupting fiow of electric current in a high voltage circuit ccmprising, rst means for interrupting circuit, a first reetifier in series with said first means and poled to conduct said current in response said hign voltage, a resistance, an inductancc, in ans connecting said resistance and inductance in series Wilh each other and in shunt with said first means for interrupting and said first rectifier, second means for interrupting circuit, a second rectifier in series with said second means for interrupting and poled to conduct said current in response to said high voltage, a condenser, a second inductance, means connecting said condenser and said second inductance in series with each other and in shunt to said second means for interrupting and said second rectifier, means for inducing in said first inductance a transient voltage adapted to reduce current fiow in said first means for interrupting to zero and for actuating said first means for interrupting t0 interrupting condition during said transient voltage, and means for thereafter in
  • each of said means for inducing comprises a condenser, a winding, means for charging said condenser to a predetermined potential, and means for rapidly discharging said condenser into said winding to provide a rapid rate of change of current in said winding.
  • a commutator system comprising, a ring transformer, a plurality of pairs of ring segments, a pair of moving brushes each contacting successive corresponding ones of said pairs of ring segments, means connecting predetermined points of said ring transformer to predetermiued ones of said ring segments, means for inducing alternating current in said ring transformer at irequency f, means for actuating said brushes at a rotative velocity of f rotations per second, a rectifier connected in series With each of said brushcs, a transformer having a primary winding and a secondary winding, means connecting said secondary winding between said rectifiers, and means for energizing said primary winding With current at frequency f.

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US70926A 1948-01-19 1949-01-14 Contact arc suppression Expired - Lifetime US2595024A (en)

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Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2848679A (en) * 1954-02-01 1958-08-19 Paul E Hochstetter Stabilization of regular voltage under severe vibration
US3064138A (en) * 1958-02-28 1962-11-13 English Electric Co Ltd Electrical impedance networks
US3437898A (en) * 1965-07-29 1969-04-08 Nat Res Dev Dynamo-electric machine including commutators fed from electronic discharge devices
US3453513A (en) * 1965-03-19 1969-07-01 Nat Res Dev Dynamo-electric machine
US3475620A (en) * 1967-12-29 1969-10-28 Atomic Energy Commission Heavy current arcing switch
US3489918A (en) * 1968-03-20 1970-01-13 Gen Electric High voltage direct current circuit breaker
US3594598A (en) * 1968-10-23 1971-07-20 Buehler Gmbh Nachf Geb Spark-suppressing commutator arrangement for electric motor
US3601603A (en) * 1969-09-11 1971-08-24 Gen Signal Corp Crossing gate control circuit
DE3626589A1 (de) * 1985-08-06 1987-02-12 Mitsubishi Electric Corp Schaltung zur betaetigung eines gleichstrom-schaltungsunterbrechers

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2188361A (en) * 1936-10-05 1940-01-30 Siemens Ag Apparatus for converting currents
US2195818A (en) * 1936-06-30 1940-04-02 Siemens Ag Apparatus for converting currents
US2293296A (en) * 1939-07-28 1942-08-18 Bbc Brown Boveri & Cie Arrangement for the sparkless interruption of currents
US2301752A (en) * 1939-07-07 1942-11-10 Westinghouse Electric & Mfg Co Arrangement for improving the commutation in contact converters
US2358926A (en) * 1941-12-24 1944-09-26 Klaus L Hansen Commutation means and a method of commutation

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2195818A (en) * 1936-06-30 1940-04-02 Siemens Ag Apparatus for converting currents
US2188361A (en) * 1936-10-05 1940-01-30 Siemens Ag Apparatus for converting currents
US2301752A (en) * 1939-07-07 1942-11-10 Westinghouse Electric & Mfg Co Arrangement for improving the commutation in contact converters
US2293296A (en) * 1939-07-28 1942-08-18 Bbc Brown Boveri & Cie Arrangement for the sparkless interruption of currents
US2358926A (en) * 1941-12-24 1944-09-26 Klaus L Hansen Commutation means and a method of commutation

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2848679A (en) * 1954-02-01 1958-08-19 Paul E Hochstetter Stabilization of regular voltage under severe vibration
US3064138A (en) * 1958-02-28 1962-11-13 English Electric Co Ltd Electrical impedance networks
US3453513A (en) * 1965-03-19 1969-07-01 Nat Res Dev Dynamo-electric machine
US3437898A (en) * 1965-07-29 1969-04-08 Nat Res Dev Dynamo-electric machine including commutators fed from electronic discharge devices
US3475620A (en) * 1967-12-29 1969-10-28 Atomic Energy Commission Heavy current arcing switch
US3489918A (en) * 1968-03-20 1970-01-13 Gen Electric High voltage direct current circuit breaker
US3594598A (en) * 1968-10-23 1971-07-20 Buehler Gmbh Nachf Geb Spark-suppressing commutator arrangement for electric motor
US3601603A (en) * 1969-09-11 1971-08-24 Gen Signal Corp Crossing gate control circuit
DE3626589A1 (de) * 1985-08-06 1987-02-12 Mitsubishi Electric Corp Schaltung zur betaetigung eines gleichstrom-schaltungsunterbrechers

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