US1713209A - Automatic reclosing circuit-breaker system - Google Patents

Description

May 14, 1929. I ANDERSON 1,713,209

AUTOMATIC RECLOSING CIRCUIT BREAKER SYSTEM Filed June 27, 1927 Arvid B. Anderson y His Attorney.

Patented May 14, 1929.

UNITED STATES PATENT OFFICE.

ARVID E. ANDERSON, OF SCOTIA, NEW YORK, ASSIGNOE TO GENERAL ELECTRIC COM- PANY, A CORPORATION OF N EW' YORK.

AUTOMATIC RECLOSING GIRCUIT BREAKER SYSTEM.

Application filedJune 27, 1527.

My invention relates to automatic reclosing circuit breaker systems and particularly to such a system in which a circuit breaker is arranged to connect a source of current to a load circuit which may or may not be energized by another source at the time the circuit breaker is reclosed. When the load circuit is not energized by another source itis desirable to reclose the circuit breaker in response to one predetermined condition thereof and when it is energized by another source it is desirable to reclose the circuit breaker in response to a different predetermined condition thereof, and one object of my invention is to pro ide an improved arrangement for controlling the reclosing of a circuit breaker under these various conditions of theload circuit. More particularly my invention relates to an improvement of the arrangement covered by my Letters Patent 1,626,495 granted'April 26, 1927.

My invention will be better understood from the following description, taken in connection with the accompanying drawing,

which shows an automatic reclosing system embodying my invention, and its scope will be pointed out in the appended claims.

Referring to the accompanying drawing, 1 is a source of current, shownas a generator, which is arranged to be connected to a load circuit 2 by means of acircuit breaker 3 which may be of any suitable type, examples of which are well known in the art. The load circuit 2 is arranged to be supplied by other source of current (not shown).

As shown in the drawing the circuit breakor 3 is of the well known contact-or type and is provided with a closing coil 4 which, when energized, maintains the circuit breaker closed. The circuit of the closing coil 1 is controlled by an overload responsive device 5 which is arranged in any suitable manner, examples of which are Well known in the art, so as to eflfect the deenergization of the closing coil 4: and the opening of the circuit breaker 3 upon the occurrence of predetermined abnormal load conditions. As shown in the drawing the overload responsive device 5 is an over-current relay whose coil is connected so as to be energized in accord ance with the current output of the source 1. The relay 5 is arranged to open its contacts 6 in the circuit of the closing coil 4 when the current output of the source lexceeds' a predetermined value.

the source voltage.

Serial No. 201,674.

which is arranged to control the rec-losing of the circuit breaker in response to the relative potentials of the source 1 and the load circuit 2 when the load circuit is energized at some other point.

As shown in the drawing the relay 8 is connected across the main terminals of the circuit breaker 3 in shunt with a load indicating resistor 9 which has a relatively high resistance so that it limits the current flowing from the source 1 to the load circuit 2 to a relatively small value, when the circuit breaker 8 is open. The amount of current through the resistor 9 however is an indication of the condition of the load circuit. It no other source is connected to the load circuit the voltage drop across the resister 9 is substantially equal to the voltage of the source 1, whereas it the load circuit is energized by some other source when the circuit breaker 3 is open, the voltage drop across the resistor 9 is considerably less than I use this difference in the "voltage drop across the resistor as a means of determining whether the reclosing of the circuit breaker shall be effected by the relay 7 or the relay 8.

The relay 8 is provided with two armatures 10 and 11 which are arranged in any suitable manner so that the armature 10 is attracted by the relay so as to open its contacts 12 when a relatively small voltage is impressed on the winding of the relay and. the armature 11 is attracted to close its contacts 13 only when a relatively high voltage is impressed on the winding of the relay 8. The contacts 12, when closed, arc'arranged to effect the completion of a circuit for the closing coil l so to close the circuitbreaker atter it has been open a predetermined length of time, and the contacts 18, when closed, are arranged to render the reclosing relay 7 operative to ciicct the reclosing of the circuit breaker in response to the voltage across 0 n (Ll) the load circuit 2. i The voltage drop across the resistor 9 that is required to cause the relay 8 to attract its armature 11 and close the contacts 13 is so great that it only occurs source 1 and the load circuit 2 is less than a predetermined relatively smaller value.

The recloslng relay 7, which is arranger to respond to the voltage of the load circuit 7 V 2, may be of any suitable type, examples of which are Well known in the art. As shown In the drawing, the relay 7 18 oil the well known polarized type comprising a polarizingwlnding 15 which is arranged to be connected across the source 1 after the circuit breaker 3 .has been open a predetermined len th of time and an o aeratin windin 16. i wh ch is arranged to be connected across the load circuit 2 when the relay 8 closes its con tacts 13. The relay 7 is arranged to close its contacts 17 when thevoltage across the load circuit exceeds a predetermined value. The contacts 17 are in a circuit for the closing coil 4. 1 The relay 7 therefore isarranged to effeet the closing of the circuit breaker 3 when the load circuit is not energized by another source and the voltage across the load circult is above a predetermined value and the relay 8 is arranged to effect the closing of the circuit breaker when the load circuit is energized by another sourceand the difierence between the voltage of the source 1 and the'load ci-rcuit 2 is less than a predetermined value. I

7 It is desirable to delay the reclosing of the,

circuit breaker for a predetermined time after it has been opened by an abnormal" load on the load circuit; or'accomplishing this IGSUlUI'PTOVlClG the overload device 5 with contacts 18which are connected in the enerizin 'circuits'of the closin coil 1 and aolarb t! b izing winding 15 of the relay 7 so that these windingsca-n be energized only when these contacts 18 are closed. 7 These contacts 18 are arranged to be opened instantly whenever the overload device 8 is operated in response to an overload and are arranged in any suitable manner, examples of'vvhioh are well known in the art, so thatgtheyarenot closed.

until after the overload device 5 has been deenerglzed fora certain length or" time; As shown in the drawing the closing of the contacts 18 isretardedc by means' of ia dashpot 19which is arranged to retardthe-movement V of the contacts only whenthey' are' closing;

2O isa controlswitch wh ch is connected in the circuits or"; tl e various'controldevices so that when it is openedit renders the reclosing equipment inoperative. 7 i

The operation of the arrangement shown in the drawing is astollows: 7 hen the circuit breaker 3 is closed and the current output of the source 1 is less than a predetermined value, a circuit for the closing coil 4 is completed from one terminal of the source 1 through contacts 21 of switch 20 which is closed, conductor 22, auxiliary contacts 23 on the circuit breaker 3, conductor 2%, contacts 6 of overload relay 5, conductor 25, closing coil 4 to the other terminal o't the source. 7 u 7 When an overload occurs so that overload relay 5 operates and opens its contacts 6 and 18 the above traced circuit for the closing coil 4 is opened so that the circuitbreakerd opens. As soon as the circuit breaker 3 opens the resistor 9 limits the current flowing from the source 1 to the loadcircuit 2 to such a smallfvalue that overload relay" contacts 6' are closed and the contacts 18 start to close,

but are delayed'in their closing movement by the'dashpot19. I I

The voltage drop across the res1stor'9 causes the relay 8 to be energized an amount depending upon the condition of the load circuit 2. It the load circuit is not'energized at some other point, the voltage drop across the resistor 9 is suflicient to cause the relay 8a to attract both of its armatures 10 and 11 so that the contacts 12 are opened and thecontacts 13are closed. It the load circuit is energized at some other point, the voltage dropacrossthe resistor 9 is sufficient only to attract the armature 1O tacts 12. r a, 7

It will be assumed first that at the time the circuit breaker 3 opens, due to the operation and open the conof the overload device 5, the load circuit is not supplied by another source. Therefore, the

contacts 13 of the relay 8 are closed and a circuit is completed across the load circuit 2 for the operating winding 16of the relay 17.

This circuit is from one side or" the load circuit' 2, through contacts'13of relay 8, conductor 26, operating winding 16' (it-relay 7 to the other side'ofthe load circuit." The" energization of the winding 16 alone is not sufficient to close the contacts 17 of the relay 7 against the force exerted by the spring 27; As soon as the contacts 18 of the overload re lay 5 are closed a circuit is completed across the source 1 for the polarizing winding 15 of the relay 7.

p This circuit is from one ter-' nnnalof the source lthrough contacts 21 of.

switch 20, conductor 22, auxiliary contacts 28 on circuit breaker 3, conductor29, contactslS of overload relay 5, conductor 30, polarizing winding 15 of the relay nnnal of the source 1.

Arslong as the resistance of the load circuit is less than a predeterminedvaluethe voltage V I drop produced by the small current that flows 7 to the other t erthrou h the resistor 9 and the load is so small that the relay 7 is not sufliciently energized to close its contacts 17. However, when the load resistance does increase above a predetermined value, the relay 7 closes its contacts 17 and completes a circuit for the closing coil 4. This circuit is from one terminal of the source 1, through contacts 21 of switch 20, conductor 22, auxiliary contacts 28 of circuit breaker 3, conductor 29, contacts 18 of overload relay 5, conductor 30, contacts 17 of relay 7, conductor 24, contacts 6 of overload relay 5, conductor 25, closing coil 4 to the other terminal of the source 1.

The circuit breaker 3 by closing its auxiliary contacts 23 completes the heretofore described locking circuit for the closing coil 4 tomaintain the closing coilenergiz'ed after the circuit breaker closes. Preferably the auxiliary contacts 23 are closed before auxiliarycontacts 28 are opened so that the look ing circuit for the closing coil 4 is completed before the above traced energizing circuit is opened.

Since the relay 8 is short-circuited by the circuit breaker 3, when it closes, its contacts 13 open and elfect the deenergization of the operating winding 16.

It will now be assumed that at the time the circuit breaker opens the load circuit 2 is supplied at some other point so that the voltage across the load circuit does not decrease to a very low value after the circuit breaker opens. The relay 8 therefore only attracts its armature 10. Since the contacts 13 of the relay 8, which are in the circuit of the winding 16, are open, the relay 7 is inoperative to effect the closing of the circuit breaker 3 although the voltage may be highenough to cause the relay 7 to close its contacts 17 if it were operative.

As long as the voltage difference between the source 1 and the load circuit is above a predetermined value, the relay 8 maintains its contacts 12 open. When the overload or other abnormal condition on the load circuit 2 is removed so that the voltage thereof is restored to suit a value that the voltage diflerence between the voltage of the source land the load circuit 2 is less than a prodetermined value, the relay 8 closes its contacts 12 and completes a circuit for the closing coil 4 if the circuit breaker 3 has been open long enough to permit the contacts 18 of the overload relay 5 to close. This circuit is from one terminal of the source 1, through contacts 21 of switch 20, conductor 22, auxiliary contacts 28 on the circuit breaker 3, conductor 29, contacts 18 of overload relay 5, conductor 30, contacts 12 of relay 8, conductor 24, contacts 6 of overload relay 6, closing coil 4, to the other terminal of the source 1. The closing of the circuit breaker 3 effects the completion of the heretofore described holding circuit for its closing coil 4 and the deenergization of the coil of relay 8 in the manner above described.

It will be observed that by opening the control switch 20 the circuit of closing coil 4 is open at its contacts 21 and the circuits through the resistor 9 and the coil of relay 8 are open at its contacts 32 so that the entire reclosing equipment is rendered inoperative.

lVhile I have in accordance with the patent statutes shown and described my invention as applied to a particular system and as embodying various devices diagrammatically indicated, changes and modifications will be obvious to those skilled in the art, and I therefore aim in the appended claims to cover all such changes and modifications as fall within the true spirit and scope of my inven-v tion.

lVhatI claim as new and desire to secure by Letters Patent of the United States, is

1. In an automatic reclosing circuit breaker system, a source of current, a load circuit, a circuit breaker for connecting said source to said circuit, means responsive to a predetermined condition of said load circuit for controlling the reclosing of said circuit breaker, and a combined selective and reclosing relay arranged to render said first mentioned reclosing means responsive to said predetsrmined condition of the load circuit under certain predetermined conditions of said load circuit and for effecting the reclosing of said circuit breaker under other predetermined conditions of said load circuit.

2. In an automatic reclosing circuit breaker system, a source of current, a load circuit, a circuit breaker for connecting said source to said circuit, means for effecting the opening of said circuit breaker, a reclosing relay responsive to the voltage across said load circuit for controlling the reclosing of said circuit breaker, and a-single relay responsive to the voltage difference between said source and said load circuit when said circuit breaker is open for rendering said reclosing relay responsive to the load circuit voltage when the voltage difference exceeds a predetermined value and for effecting the closing of said circuit breaker when the voltage difference is less than a predetermined value.

3. In an automatic reclosing circuit breaker system, a source of current, a load circuit, a circuit breaker for connecting said source to said circuit, means for effecting the opening of said circuit breaker, a reclosing relay including an operating winding, and a relay responsive to the voltage difference between said source and said load circuit when said circuit breaker is open for connecting said operating winding across said load circuit when the voltage difierence exceeds a predetermined value and for effecting the reclosing of said circuit breaker when the voltage difference is less than a predetermined value.

1 4. In an automatic reclosing circuit breaker said circuit-,overload responsive means for effecting the opening of said circuit breaker,

system, a source of current, a load circuit, a circuit breake'rtor connecting saidsource to current limiting means arranged to be connected in series between said source and load circuit when said circuit breaker is open,..el-ectroresponsive means arranged when, energized to effect the closing of said circuit breaker, an energizing circuit for said electroresponsive means, contacts in said ener- V gizing circuit arranged to be closed by said "overload responsive means a system, a source of current, a load circuit, a

circuit breaker for connecting said source to said circuit, overload responsive ineanstor effecting the opening of said circuit breaker, current limiting means arranged to be connected in series between said source and load c1rcu1t'wien said c1rcu1t breaker is open, electrores )onsive 'means arran 'ed when ener- I I: 1 e n glzed to effect the closing ot said circuit breaker, an energizing circuit for s id electroresponsive means, contacts in said energizing circuit arranged to be closed by said 1' said circuit breaker has been open a predetermined length of time, other contacts in said energizing cir-- cuit, a reclosing relay including a voltage Winding for controlling certain of said other contacts, and a relay responsive to the voltage drop across said current limiting means for effecting the connection of saidvoltage windcircuit when the voltage drop across said current limiting means exceeds a predeter mined value and for effecting the closing of other of said other contacts when the voltage ditlerence is less than a predetermined value.

6. In an automatic reclosing circuitbreaker system, a source of current, load circuit, a circuit breaker torconncctinglsaid source to said circuit, overload responsive means for effecting the opening of said circuit breaker, currentlimiting means arranged to be conneeted in series between said source and load circuit when said circuit breaker is open, elcctroresponsive means arranged when energized to effectthe. closing oi'said circuit breaker, an energizing circuit for said electroresponsive means, parallel connected contacts in said energizing circuit, a reclosing relay comprising a polarizing winding and an operating winding torcontrolling certain of said contacts, a relay responsive to the voltage drop across said' current limiting means for connecting the operatingwinding of said reclosing relay across said load circuit when the voltage difference exceeds a {mode terinined value and tor-"controlling other of said parallel connected contacts, other contacts in said energizing circuit and the'circuit of said polarizingwinding and means for closing 'said' last mentioned contacts after said circuit breaker has been open a predetermined length of time. o I

In witness whereof, I have hereunto set my hand this 25th day of June 1927.

anvin E. Alanna-son,

45 ing of'said reclosing relay across said load

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