US1676316A - Automatic reclosing circuit-breaker system - Google Patents

Description

July 10 1928. 1,676,316

A. E. ANDERSON AUTOMATIC RECLOSING CIRCUIT. BREAKER SYSTEM Original Filed Aug. 25, 1924 Invent or His Attorney Patented July 10, 1928. I

UNlTED STATES PATENT oer-"Ice.

AltVID E. ANDERSON, 01' SCOTIA, NEW YORK, ASSIGNOB TO GENERAL ELECTRIC COIPANY, A CORPORATION NEW YORK.

AUTOIA IIC REGLOBING CIRCUIT-BREAKER SYSTEIQ Application filed August 25, 1924, Serial No. 788,918. Renewed February 8, 1927.

My invention relates to automatic reclosing circuit breaker systems and one object of my invention is to provide an improved system for effecting the closing of a circuit a breaker which is arranged to connect together twocircuits whenever one of the circuits s energized and the other circuit is free from short circuits and overloads.

My invention will be better understood In from the following description taken in connection with the accompanying drawing which shows an automatic reclosing circuit breaker system embodying my invention, and its scope will be pointed out in the appended claims.

Referring to the drawing, 1 represents a circuit breaker which is arranged to connect together the two conductors 2 and 3 of two 1 direct current electric circuits which may be energized independently of each other by one or more sources of current (not shown). In order to simplify the drawing, it is assumed that the'ground is the other, side of both of the circuits which the circuit breaker 1 is arranged to connect together.

The circuit breaker 1 may be of any suit-- able ty e which is arranged to be opened upon t e occurrence of a predetermined abnormal condition on one of the circuits so when the circuit breaker is closed. As shown, the circuit breaker 1 is provided with a closing coil 4, which, when energized,

maintains the circuit breaker in its closed position. "trolled by an overload relay 5 which is connected in any suitable manner so'as to be responsive to the current flowing between .the two circuits when the circuit breaker is closed. The relay 5 is arranged so that it to does not afl'ect the deenergization of the coil 4 until the current flowing between the two circuits exceeds a predetermined value.

The closing of the circuit breaker 1 is controlled by means of a reclosing relay fi' which is adapted to control the circuit of the coil 4, when the circuit breaker is open, so that it is completed whenever one circuit is energized and the load, connected to the other circuit is above a predetermined amount;

.50 The reclosing relay 6 is a difierential relay having a restraining coil 8 and an operating coil 9 These two coils are arranged to be connected so that the relative forces of the two coils va The circuit of the coil 4 is conin accordance with the resistance of the (uni when con-.

nected to one of the circuits w en the circuit breaker'is open and the other e -rcuit is enerized. In m copending application, Serial 0. 571,183 ed June 27 1922, I have disclosed and claimed an automatic reclosing circuit breaker system employing a reclosing relay of this type.

As shown in the drawing, the coil 8 is connected across the" current limiting resistor 10, which is connected in series with the conductors 2 and 3 when the circuit braker 1 is open, so that the coil 8 is energized in accordance with the current flowing through the resistor, and the coil 9 is arranged to be connected between the conductor 2 and ground by the voltage relay 11 when the voltage between the conductor 2 and ground is above a predetermined value, and be-' tween the conductor 3 and ground by the voltage relay 12 when the voltage between the conductor 3 and ground is above a predetermined value. The circuits of the volt age relays 11 and12 preferably are controlled by the circuit breaker 4 so that they are energized only when the circuit breaker isopen. Also suitable means, such as dashpots on the relays 11 and 12, are provided whereby the circuit of the coil 9 of the relay 6 is not completed until after the circuit breaker has been open a certain length of time.

It will be evident, therefore, that whenever the circuit breaker 1 opens due to a short circuit or an overload on one of the circuits, the restraining coil 8 is energized to maintain the contacts of the relay 6 open against the pull of the coil 9, which is connected across the circuit, which is not overloaded, after the circuit breaker has been open for a certain length of time. As soon as the resistance of the overload has increased above a predetermined value, the actuating coil 9 overpowers therestraining coil 8 and eifects the closin'gcof the circuitbreaker in amaniler hereinafter described,

'In order to prevent the relays 11 and 12 from connecting the conductors 2 and 3 directly together in case the contacts of both relays are closed simultaneously, a resistor 14' is provided. This resistor is arranged so that it is connected in series with-the coil. 9 when the contacts of one of the reiays 11 and 12 are closed and is connected inseries he tween the eonduetois 2 and-3 when the contacts of bothof the relays 11 and 12ers follows "When the circuit breaker,1 is closed and the load conditions are normal a circuit is completed for the closing coil 4 of the circuit breaker 1 from the conductor 3, through the auxiliary contacts 15 on the circuit breaker 1, contacts 16 of the overload rela 5, closing coil t to ground.

Upon the occurrence of an overload or short circuit on one of the circuits, the overload relay 5 opens its contacts 16whereupon the circuit breaker 1 opens and inserts the current limiting resistor 10 so thatcurrent flows through the resistor to the overload or short circuit. Since the resistance of the resistor 10 is very high relative to the normal load resistance, substantially full voltage is impressed on the restraining coil 8 of the reclosing .relay 6 so that this relay cannot close. its contacts 17.

The closing of the auxiliary contacts 18 on the circuit breaker connects the voltage relay 11 between the conductor 2 and ground and the voltage relay 12 between the conductor 3 and ground. After a predetermined-time the voltage relay, which is connected to the circuit across which the overload or short circuit is not connected, closes its contacts, provided this circuit is energized independently of the other circuit.

Let it be assumed, for example, that a short circuit is connected between the conductor 3 and ground and that there is normal voltage between conductor 2 and ground. Under these conditions the relay l1 closes its contacts 19 but the relay 12 does not close its contacts 20 because the voltage between conductor 3 and ground is too low. The closing of the contacts 19 connects the actuating coil 9 and the resistor 14 in series between the conductor 2 and ground. The resistor 14 is low relative to the resistance of the coil 9. Therefore, substantially normal voltage is impressed across the coil 9. The relay 6, however,is designed so that it cannot close its contacts 17 when substantially equal voltages are impressed across both coils thereof.

, As the short circuit or overload is re duced, the voltage across the restraining coil 8 decreases but the voltage acro:s the actuating coil 9 remains constant so that the relative forces exerted by the two opposing coils vary with the resistance of the overload or short circuit. When the overload has decreased to a predetermined value, the force exerted by the coil 9 exceeds the restraining force exerted by the coil 8 and the auxiliary contacts 15 on the circuit breaker- 1, when it is closed, completes the heretofore described circuit for the closing coil 4; and the opening of the auxiliary contacts 18 de energizes the relays 11 and 12 whereupon these two relays and the reclosing relay 6 are restored to their normal position.

In case the overload or short circuit is between the conductor 2 and ground and full voltage is impressed across the conductor 3 and ground, the rela 12 closes its contacts 20 instead of the re ay 11 closing its contacts 19. Therefore, in this case the actuating coil 9 and the closing coil 4 are con nected between the conductor 3 and ground instead of (between the conductor 2 and ground during the reclosing operation of the system. a a

It will be observed that in case the contacts-19 and 20 are closed simultaneously due to the voltage across both circuits being high enough, after the opening of the circuit, to cause both of the relays 11 and 12 to operate, the conductors 2 and 3 are connected together through the contacts 19 and 20, but the resistor 14 limits the current through these contacts to a safe operating value. In my co-pending application, Serial No. 666,- 421 filed October 3, 1923, I have disclosed and claimed anautomatic reclosing circuit breaker system embodying this feature.

While 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 allsuch changes and modifications as fall within the true spirit and scope of my invention;

What I claim as new and desire to secure hy Letters Patent of the United States, 1s: a

1. In an automatic reclosing circuit breaker system, two electric circuits, 0. circuit breaker arranged to connect .said circuits together,- current limiting means arranged to be connected inseries with said circuits when said circuit breaker is open, a reclosing relay for controlling the closing of said circuit breaker having a voltage winding, means for connecting said winding to one point on said current limiting means while said circuit breaker is open, and means responsive to a predetermined voltage across one of said electric circuits for connecting said winding to another point on said cur rent limiting means while said circuit breaker is open.

2. In an automatic reclosing circuit breaker system, two electric circuits, a c ir cuit breaker arranged to connect said circuits together, current limiting means, a reclosin relay for controlling the closing of said circuit breaker having a voltage wlnding, means for connecting said winding across one of said electric circuits with said current limiting means in series therewith after said circuit breaker has been open for a predetermined length of time, and voltage responsive means -for completing a circuit for said relay winding across the other electric circuit when the voltage across one of said electric circuits exceeds a predetermined value after said circuit breaker has been open for a predetermined length of time.

3. In an automatic reclosing circuit breaker system, two electric circuits, a circuit breaker for connecting said circuits to"- gether, current limiting means arranged to be connected in series with said electrlc circuits when said circuit breaker is open, a reclosing relay for said circuit breaker having a Volta winding, and means for connecting sai voltage windin of said reclosing re ay to one point on,sa1d current limiting means when the voltage of one of said circuits is above a predetermined value, and for connecting 'said voltage winding to another point on said current limiting means when the voltage of the other one of said circuits is above .a predetermined value.

4. In an automatic reclosin circuit breaker system, two electric circuits, a circuit breaker for connecting said circuits together, a reclosingv relay for said circuit breaker having a voltage winding, current limiting means, and voltage responsive means for connecting said voltage winding of said reclosing relay across one of said electric circuits, with said current limiting means in series therewith when the voltage across said one of said electric circuits is above a predetermined value, and across the other one of said electric circuits independ 'ently of said current limiting means when the voltage across said other one of said elelctric circuits is above a predetermined va ue.

5. In an automatic reclos' circuit breaker system, two electric circuits, a circuit breaker for connecting said circuits together, current limiting means arranged to be connected in series with said electric circuits when said circuit breaker is open, a differential relay for controllingthe reclosing age of the other one of said electric circuits is above a predetermined value.

- 6. In an automatic reclosing circuit breaker system, two electric circuits, a circuit breaker for connecting said circuits together, reclosing means for said circuit breaker, a control relay for said reclosing means having two windings adapted to be connected so that the removal of a short circuit or overload on one of said circuits when said circuit breaker is open automatically changes the relative forces exerted by said windings, current limiting means, and voltage responsive means for connecting one of the windings of said relay across one of said electric circuits with said current limiting means in series therewith when the voltage across said one of said electric circuits is above a predetermined value, and across the other one of said electric circuits independently of said current'limiting means when the voltage across said other one of said electric circuits is above a predetermined value.

7. In an automatic reclosing" circuit breaker system, two electric circults, a circuit breaker for connecting said circuits together, current limiting means arranged to be connected in series with said circuits when a said circuit breaker is open, reclosing means for' said circuit breaker, a control relay for said reclosing means having two windings adapted to be connected so that the removal of a short circuit or overload on one of said circuits when said circuit breaker is open automatically changes the relative forces exerted by said windings, means for connecting one of said windings of said relay to one point on said current limiting means 5 and voltage res on'sive. means for connectin said one c said windings to another point on said current limiting means.

8. In an automatic reclosing circuit breaker s stem, two electric circuits, a circuit breaker for connecting said circuits together, reclosing means for said circuit breaker, a control relag for said reclosing means having two win ings adapted to e connected so that the removal of a short circuit or overload on one of said circuits when said ing one of said windings of said relay across no one of said circuits with said current limiting means in' series therewith after said circuit breaker has been open a predetermined length of time, and voltage responsive means for connecting said one of the windings of.

said relay across the'other one of said electric circuits. I

9. In an automatic reclosing circuit breaker system, two electric circuits, .a circuit breaker for connecting said circuits together, current limiting means arranged to be connected in series with said electric circuits when said circuit breaker is open, a differential relay for controlling the closing of said circuit breaker having a winding connected so as to be energized in accordance with the current through said current limiting'mea-ns and a voltage winding, a second current limiting means, and voltage responsive means operative after said circuit breaker has been open' a certain length of time to connect said voltage winding across one of said electric circuits with said second current limiting means in series therewith and across the other one of said electric circuits independently of said second current limiting means.

10. In an automatic reclosing circuit breaker system, two electric circuits, a circuit breaker for connecting said circuits together, current limiting means arranged to be connected in series with said electric circuits when said circuit breaker is open, a difierential relay for controlling the ,closing of said circuit breaker having a winding connected so as to be energized in accordance with the current through said current limiting means and a voltage winding, a second current limiting means, a voltage relay connected so as to be responsive to the voltage across one of said electric circuits and adapted to connect said second current limiting means and the voltage winding of said differential relay across said one of said electric circuits when the voltage across said one of said electric circuits is above a predetermined value, and a second voltage relay connected so as to be responsive to the voltage across the other one of said electric circuits and adapted to connect said voltage winding 7 of said differential relay across said other one of said-electric circuits when the voltage across said other one of said electric circuits is above a predetermined value.

11. In an automatic reclosing circuit' breaker system, two'ele ctric circuits, a circuit breaker for connecting said' circuits to gether, means for effecting the opening of said circuit breaker upon the occurrence of a predeterminedabnormal condition on said circuits, current limiting means arranged to be connected in series with said circuits when said circuit breaker is open, a closing coil for said circuit breaker, a differential, relay for controlling the circuit of'said closing said circuit breaker in the circuit coil having a restraining winding connected so as to be energized in accordance with the current through said current limiting means and a voltage winding, a time delay relay arranged to be connected across one of said 10 electric circuits in response to the opening of said circuit breaker to effect the connection of said voltage winding of said differential relay to a point on said current limiting means when the voltage of said one of said electric circuits is above a predetermined value, and a second time delay relay arranged to be connected across the other one of said electric circuits in response to the opening of said circuit breaker to efiect the connection of said voltage winding of said differential relay to a second point on' said current limiting means when the voltage of said other one of said electric circuits is above a predetermined value.

12. In an automatic reclosing circuit breaker system, two electric circuits, a circuit breaker for connecting said electric circuits, a reclosing relay having a voltage winding, means for effecting the opening of 00 said circuit breaker, means responsive to the opening of said circuit breaker for efl'ecting the connection of said voltage winding across ne of said circuits while said circuit breaker is open, means responsive to the voltage across the other of. said circuits while said circuit breaker is open for connecting said voltage winding across said other. electric circuit when the voltage thereof is above a predetermined value, and current limiting means connected in series with said voltage winding when it is connected to one of said electric circuits and arranged to be connected in series between said electric circuits only when said winding is simultaneously connected across both of said electric circuits.

13. In an automatic reclosing circuit breaker s'stem, two electric circuits, a circuit brea er for connecting said circuits, means for effecting the opening of said circuit breaker, a reclosing relay having a voltage winding for controlling the reclosin of said circuit breaker, a relay arranged w en energized a predetermined amount to connect said voltage winding across one of said electric circuits, another relay arranged when energized-a predetermined amount to connect said voltage winding across the other electric circuits, a circuit for one of 12 said relays across one of said electric circuits,

' a circuit for the other relay across the/ other electric circuit, and auxiliary contats on of each relay.

14. In an automatic reclosing circuit breaker s stem, two electric circuits, a circuit bre er for connecting said circuits, means for'eflecting the opening of said circuit breaker, a reclosing relay having :1. volt- 139 age winding for controlling the reclosing of said circuit breaker, a time relay arranged when energized a predetermined amount to connect said voltage winding across one of said electric circuits, another time relay arranged when energized a predetermined amount to connect said voltage Winding across the other electric circuit, a circuit for one of said time relays across one of said 10 electric circuits, contacts in said time relay circuit arranged to be closed by said circuit breaker when open, a circuit for the other time relay across the other electric circuit,

and contacts 1n said last mentioned time relay circuit arranged to be closed by saidcir- 15 ABVID E. ANDERSON.

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