US1701351A - anderson - Google Patents

Description

Feb. 5, 1929.

A. E.- ANDERSON AUTOMATIC RECLOSING CIRCUIT BREAKER SYSTEM Filed April 28. 1926 Inventor- ArvLd iiAnolerson,

HLs Attorney.

an tem.

Patented Feb. 5, 1929. v

UNITED STATES 1,701,351 PATENT] OFFICE.

ARVID E. ANDERSON, OF SCOTIA, NEW YORK, ASSIGNOR TOGENERAL ELECTRIC COM- PANY, A CORPORATION OF N EW YORK.

AUTOMATIC imcLosme CIRCUIT-BREAKER sys'rnmq Application flled April 28, 1926. Serial No. 105,294. g

- My invention relates to automatic reclos- .ing circuit breaker systems and particularly "to a system in which both circuits, which are arranged to be connected together by thecircuit breaker, are adapted to be energized independently of each other, and in such a way that at certain times they may have different polarities with respect to each other.

One object of my invention is to provide an automatic reclosing circuit breaker system which, under certain electrical conditions of the two circuits, operates to connect the two. circuits together'but which is rendered cuit breaker when the polarity of one of the In the accompanying drawing, Fig. 1 is a diagram of an automatic reclosing circuit breaker system embodylng my invention, and

' 2'5 Fig. 2 is a diagram of another type of automatic reclosing circuit breaker system embodying my invention.

Referring to Fig. 1, 1 and 2 respectively represent conductors of twoindependently energized direct current electric circuits which are arranged to be connected together by a circuit breaker 3 which may be of any suitable type, examples of which are well known in the art. The ground constitutes the other side of both circuits, but it is evident that my invention is not limited to a grounded system, but is equally applicable to an ungrounded system in which metallic conductors constitute both sides of the sys- The circuit comprising the conductor 1 and ground is arranged to be energized by a suitable source 4, and the circuit comprising t'he'conductor 2 and ground is arranged to be energized by a suitable source 5, which has the same polarity as the source 4 and also by a suitable source 6 which has the opposite polarity. \Vhile I have shown separate sources 5 and 6 for reversing the polarity of I the circuit comprising the conductor 2 and the ground, itis evident that the polarity of this circuit may be reversed in any other well known means such as by means of a reversing switch, examples of which are old and well known in the art, between either of the inoperative to effect the reclosure of the circircuits is reversed with respect to the other.

sources 5 or 6- and the circuit. The circuit breaker 3 is normally held closed by its closing coil 7, which'is connected between conducto'r'2 and ground through contacts 8 of an overload'rel'ay 9, the'coilof which is connected so thatit is energized inaccordance with the amount of currentthat flows from one circuit to the other j'vhenthe circuit breaker is closed. Therefore, he circuit of the closing coil 7 "is p eaand Ithe circuit breaker 3 opens whenever i abnormal load is connected to either lectric'circuit that sufiicient; current flows tria-eg s; the overload relay tojcause it to open its'contacts 8.

After the circuit breaker 3 has been open for a certainlength' of time, it is desirable to reclose the circuitbreakel,.asjsoon as the abnormal'load is removed. "fl he automatic reclosing equipment shown in t sfigure is similar to that disclosed andclaim'ed in my copending applicat Qn, Serial 733,918, filed August 23,1924. This reclo sing equipment comprises a load indicating resistor 10 which is connectedin seri'es'betwe'en the conductor 1 and 2 when'the'circuit bre'aker is open, two time element olt'a'ge'relaysll and 12 which are respectively connectedbetween the conductors 1 and Q'and the ground by the auxiliary contacts 13 on thecircuit breaker when it is in its open position, and a 'reclosing relay 14 which is controlled by the relative voltages of the two electric circuits to effect the closing of the circuit breaker. The two time tivecircuits. Therefore, only the voltage re-' lay which is connected acrossthe normal circuit picks up after the circuit breaker is opend by an abnormal condition on one of the circuits. This relay, after a predetermined time, connects the operating coil 15 of the reclosing relay 14 across whichever circuit is normal. The opposing coil 16 of the reclosingrcl'ay 14,:which is a balance differential relay, is connected in parallel with the load indicating resistor 10. So long'as an abnormal load remains connected to either circuit, suflici'ent current flows through the opposing coil 16 of the reclosing relay 14 to prevent the operatingcoil 15 from closing the relay contacts 17 which are in the closing circuit of the closing coil 7 of the circuit breaker.

Itwill be observed that so lon as both of the electric circuits are energize by sources of the same polarity the greatest voltage that can exist across the resistor 10 and the coil 16 of the reclosing relay when the circuit breaker is open is the voltage of the normal source, and this voltage is impressed thereon only when a short circuit exists on the faulty circuit at a point near the circuit breaker 3. If, however, the circuits are energized so that they have opposite olarity, the voltage across the resistor 10 an the coil 16 of the reclosing rela 14 .becomes the sum of the voltages across t e two circuits instead of the difference, so that the reclosing relay maintains its contacts 17 0 en although" the voltages of the two circuits have the proper values to effeet the reclosure of the circuit breaker. Since it is customary to design the resistor 10 and the coil 16 only for the normal voltage of thecircuits, it is desirable to provide an arrangement for protecting these devices from the abnormal voltage which is impressed thereon when both circuits are energized at substantially normalvolta e of the opposite a polarity. For accomplishing this result, I provide a lockout relay 20 which is connected between the conductors 1 and 2 when the circuit breaker 3 is open, and which is designed so thatit picks up when the voltage impressed on its coil is greater than the normal voltage of either circuit in order that under normal voltage conditions the relay never operates. The lockout relay 20 controls thecircuit of a control relay 21, which in turn controls the connectionof the resistor 10 and the coils of the reclosing relay 14 and the time element voltage relavs 11 and 12 so that they are all disconnected when the circuits are ener 'zed in such a manner that the polarity 0 one circuit is reversed with respect to the polarity of the other.

The operation of the arrangement shown in Fig. 1 is as follows :W'hen both of theelectric circuits are energized by sources of the same polarity and the load conditions on both circuits are normal, the circuit breaker is held closed by the closing coil 7 whose circuit is completed from the conductor 2 through contacts 22 of the control relay 21, conductor 23, auxiliary contacts 24 on the circuit breaker 3, conductor 25, contacts 8 of the overload relay 9, conductor 26, closing coil 7, to ground. The main contacts of the circuit breaker 3 short circuit the resistor 10, the coil 16 of the reclosing relay 14 and the coil of the lockout relay 20; Since the auxiliary contacts 13 on the circuit breaker 3 are open both of the voltage relays 11 and 12 are deenergized and the circuit of the operating coil 15 of reclosing relay 14 is open at the contacts of the voltage relays 11 and 12.

When an abnormal load condition occurs on either of the two electric circuits so that a current in excess of the setting of the overload relay 9 fiows through the circuit breaker 3, the overload relay 9 opens its contacts 8 and effects the opening of the circuit breakerf ficiently energized to close its contacts 28. The relay 11, however, is connected across the normal circuit so that it closes its con-. tacts 29 a predetermined time after thecir cuit breaker opens.

The opening of the main contacts oflthe;

circuit breaker 3 removes the short circuit from around the resistor 10, the coil 16 of the reclosing relay l4 and the coil of. the lockout relay 20. The resistor 10 limits to a relatively smallvalue the amount of current that flows from the normal circuit to the faulty circuit. The coil 16 aids the spring .30 to maintain the contacts 17 of the reclosing relay open. The lockout relay 20 remains in theposition shown in the drawing if the voltage.

etween the main contacts of the circuit breaker is less than a predetermined value.

\Vhen the time element voltage" relay '11.

closes its contacts 29 a circuit is completed for the operatin coil 15 of the reclosing'relay 14 from conductor 1 through contacts 31 of the control relay 21, conductor 32, contacts 29 of relay 11, resistor 33, conductor 34, coil 15 to ground. 5

So long as an abnormal load remains connected between conductor 2 and ground the volta e difference between the two circuits is suc that the pull of the coil 16 of the reclosing relay 14 predominates and prevents the contacts 17 of the relay from being closed;

When, however, the abnormal load is removed from between conductor 2 and ground,

the pull of the coil 15 of the reclosing relay 14 predominates and causes the contacts 17 of the relay to be closed. The closing of the contacts 17 comletes the closing circuit for the closing coil from conductor 1, through contacts 31 of the control relay 21,

conductor 32, contacts 29 of relay 11, resistor a.

33, conductor 34, contacts 17 of relay 14, conductor 25, contacts 8 of overload-relay 9,

conductor 26, closing coil 7, to ground. The

circuit breaker, by closing its auxiliary con- It is evident that if the abnormal load is 2 connected between conductor land ground the operation is similar to that above described. except that relay 12 closes its contacts 28 instead of relay 11 closing its contacts 29 in response to the opening of the circuit breaker. *-Therefore, the operating coil and the closihgcircuit of the closing coil 7 are connected between conductor 2 and ground instead of between conductor 1 and ground.

Heretofore it has-been assumed that the faulty circuit is separately energized when i the circuit breaker is open, so that its polarity is the same as the normal circuits, and therefore the voltageimpressed upon the coil of the lockout relay is not great enough to cause the relay 'toclose its contacts 36. If,

however, the faulty section should be energized so that its polarity is reversed with respect to the polarity of the normal section, the voltage impressed upon the winding of the lockout relay 20 is the sum of the two voltages across the two circuits. The relay 20 is designed to pick up at a predetermined voltage, which is somewhat greater than the maximum normal voltage of either circuit.

When the lockout'relay 20 picks up and closes its contacts 36, a circuit is completed for the coil ofthe control relay 21 from con ductor 2 through contact 36 of the lockout relay 20, coil of relay 21, to ground. The re lay21 opens itscon'tacts 22 and 31, so that the resistor 10 and the coil 16 of the websing relay Mare disconnected from between the conductors 1 and 2 and the circuits of the polarity, the relay 20 opens its contacts 36,-

thereby effecting the deenergization of the relay 21 and .theclosing of the contacts 22 and 31 to render the automatic reclosing equipment again operative to reclose the circuit brea'ker as soonas the load conditions are normal: a v

In Fig. 2 I'have shown my invention in connection with a" difi'erent type of automatic reclosing circuit breaker system, which, however, is old and well known in the art. In this embodiment of my invention the circuit breaker is reclosed only when both circuits are independently energized and the voltage across 'each circuit is substantially normal. As shown, the circuit breaker 50, which is arranged to connect together the conductors'51- and 52 of two independently energized electric'circuits', is of the well known latched-in type which is held in its closed position by a latch 53. The latch is arranged 'to be releaseidi byan overload coil 53 which is connected so as to be energized in accord-' ance with the current flowing fromone conductor to the other when the circuit breaker is closed. When the circuit breaker 50 is its contacts 61 and 62 unless the voltage beo en'ed, a time delay device 54, which may be 0 any suitable type, examples of which are well known in the art, is released, which closes the contacts 55 a predetermined time after the circuit breaker opens. The closing of the contacts 55 connects the coil of a voltage re- 56 between conductor 52 and the other side the circuit, which, in the arrangement shown, is the ground. As soon as the voltage of the circuit comprising the conductor 52 and ground exceeds a predetermined value,- the relay 56 closes its contacts 57 and'connects the closing coil 58 of the circuit breaker 50 I between conductor 51 and ground. The clos I 'ing coil 58 is so designed that it closes the circuit breaker when the voltage impressed across it is above a predetermined value. It is obvious, therefore, that whenever the cir-- cuit breaker is open, each circuit has to be independently energized and the voltageacross each circuit has'tobe above a certain value in order to close the circuit breakenl In order to prevent the circuit breaker from being reclosed when the 'circuits are" independently energized by sourcesof'oppd' site polarity, I provide thelockoutrelay 60' which is connected across the main termi nals of the circuit breaker. This relay 60 is so designed thatit does not pickup and'open tween conductors 51 and 52 exceeds a predet'er mined value which is greater than the normal voltage of either circuit. The contacts 61 are in the circuit of the coil of relay 56 and the contacts 62 are in the circuit of the closing coil so that when relay 60 is operated by one of the circuits being energized with an opposite polarity, the reclosing equipment is rendered inoperative to effect the closing of the circuit breaker.

While I have, in accordance with the patent statutes, shown and described my invention in connection with particular systems and as embodying various devices diagrammati cally indicated, changes and modifications no will be obvious to those skilled in the art and I, therefore, aim in the appended claimsto cover all such changes and modifications as fall within the true spirit and scope of my invention. I

What I claim as new and desire to secure byLetters Patent of the United States, is

1. In an automatic reclosing circuit breaker system, two direct current electric circuits a'rranged to be energized independently of each 12 other, a circuit breaker for connecting said circuits together, means for efiecting the opening of said circuit breaker, electroresponsive means responsive to predetermined electrical conditions of said circuits for effectv125 ing the reclosing of said circuit breaker, andmeans controlled by the relative polarities of said electric circuits for controlling the com nections of said electroresponsive means so as to render said electroresponsive means unresponsive to said predetermined electrical conditions when the polarity of one of said circuits is reversed with respect to the other while said circuit breaker is open. 7

2. In an automatic reclosing circuit breaker system, two electric circuits arranged to-be ener ized independently of each other, a circuit breaker for connecting said circuitsto gether, means for effecting the opening of said circuit breaker, current limiting means arranged to be connected in series between said circuits when said circuit breaker is open, means for reclosing said circuit breaker in res onse to predetermined electrical conditio'n'sofsaid circuits, and means arranged to render said reclosing means inoperative and to disconnect said current limiting means from between said circuits when the polarity of one'fof said circuits is reversed with respect to the other while said circuit breaker is open. Y

3. Inan automatic reclosing circuit breaker system,;.-.two electric circuitsarranged to be ener med-independently of each other, a circuit reaker for connecting said circuits together,.means-.for effectingthe opening of said circuit breaker, means controlled by the difference between the voltages'ofsaid circuits foreflecting the reclos'ure of said circuit breaker, and a relay-connected so as to be responsiveto the difl'erence between the voltages of said circuits andoperative in response to 'a'predetermined voltage which is higher'than the normal'voltage of either circuit to render said reclosing means inoperative.

4. In an automatic reclosing circuit breaker system, two electric circuits arranged to be energized independently of each other, a circuit breaker for connecting said circuits together, means for effecting the opening of said circuit breaker, current limiting means arranged to be connected in series between said circuits when said circuit breaker is open, means controlled by the difference between the voltages of said circuits for effecting the reclosure of said circult breaker, and

V a relay connected so as to be responsive to the difference between the voltages of said circuits when said circuit breaker is open and operative in response to a predetermined voltage which is higher than the normal voltage'of either circuit to render said reclosing means inoperative and to disconnect said current limiting means from, between said circuits. v v

5. In an automatic reclosing circuit breaker system, two electric circuits arranged to be energized independently of each other, a circuit breaker for connecting said circuits together, means for effecting the opening of said circuit breaker a reclosing relay for controlling the reclosing of said circuitbreaker having a winding arranged to be connected cuit breaker whenever the loo when the circuit breaker is 0 energized in accordance wi between the voltages of said circuits, and snother relay connected so as to be responsive to the difference between the voltages of said circuits and operative in res use to 0. predetermined voltage which is ighor than the normal voltage of either circuit to disconnect said reclosing relay winding so that it is unresponsive to the voltage diflorence between said circuits.

6. In an automatic reclosing circuit breaker.

system, two electric circuits arran to be energized independently of each or, s circuit breaker for connecting said circuits together, means for effecting the ning, of said circuit breaker, current limitm means arranged to be connected in series ween said circuits when said circuit breaker is open, a reclosin relay for controlling the reclosing of sai circuit breaker having a winding connected in parallel with said current limiting means, and a rela connected in parallel with said current limiting means and arranged when the vol impressed thereon exceeds a predete value to disconnect said current limi moons and said reclosing relay from in SCI'IQS between said circuits.

so that itis 5 the diflcrence system, two direct current electric circuits arranged to be ener ized independently of each other, a circuit resker for connecting said circuits together, means for electing the opening of said circuit breaker, means controlled by the volta e acros one of said circuits for effecting t e rec v on said one of said circuits is less than s predetermined amount and the other circuit is energized, and means for removing said vol controlled means from the control of said voltage when said circuits are energized so that they have opposite polarities.

8. In an automatic reclosing circuit breaker system, two electric circuits to be ener ized independently of each or, a circuit breaker for connecting said circuits together, means for effecting the opening of said circuit breaker, means control ed by the voltages across said circuits for effecting the reclosing of said circuit breaker, and a rels erative to effect the closing of said circuit breaker.

In witness whereof, I have hereunto set my hand this 27th day of April, 1926.

' ARVID E. ANDERSON.

of said cir- I

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