US1769168A - Automatic reclosing circuit breaker - Google Patents

Description

July 1, 1930.

E. w. SEEGER 1,769,168

AUTOMATIC RECLOSING CIRCUIT BREAKER Filed May 2 1925 INVEN TOR.

6mm 19). .g/aggm.

ATTORNEY Patented July 1, 1930 UNITED STATES PATENT OFFICE EDWIN W. SEES-ER, OF MILWAUKEE, WISCONSIN, ASSIGNOR, BY MESNE ASSIGNMENTS,

TO CUTLER-HAMMER, INC., A CORPORATION OF DELAWARE 1 AUTOMATIC nEcLosINe cmcorr BREAKER Application filed May 2,

Thisinvention relates to automatic reclosing circuit breaker systems.

The invention is particularly applicable to automatic reclosing circuit breaker systems wherein reclosure of the circuit breaker is controlled in accordance with the resistance of the load circuit.

In systems of the aforesaid character it has heretofore been necessary to employ circuit breakers and relays of special types and to also provide mechanical interlocks between certain of the control parts.

An object of the present invention is to provide an automatic reclosing circuit breaker in which the circuit breaker and the relay control means may be of conventional design. Another object'is to provide an automatic reclosing circuit control system of the aforesaid character which functions without the 2 use of mechaniealinterlocks to thereby render the system more reliable in operation.

Another object is to provide an automatic reclosing circuit breaker having a minimum number of control parts.

Various other objects and advantages of the invention will hereinafter appear.

The accompanying drawing diagrammati cally illustrates certain embodiments of the invention which will now be described it being understood that the embodiments illustrated are susceptible of modification without departing from the spirit and scope of the appended claims. y

In the drawing:

Figure 1 diagrammatically illustrates one embodiment of the invention; and

Fig. 2 diagrammatically illustrates a modification of the system shown in Fig. 1.

Referring to Fig. 1 the same illustrates feed lines L and L and a load to be connected therebetween said load being indicated by reference character 1. The continuity of the load circuit is controlled by a circuit breaker 2 biased towards open position and having an operating winding 3 for holding the same in closed position. Winding 3 is adapted to be connected across lines L and L through the medium of a manuall controlled switch 4 and a normally close electromagnetic relay 5. Relay 5 is biased to- 1925. Serial No. 27,355.

wards closed position and is provided with an operating winding 6 and a holding winding 7. Also, said relay has a dash pot 8 associated therewith for retarding closing movement thereof.

Winding 6 is permanently-connected in series in the load circuit. while winding 7 is connected across circuit breaker 2 so that the same is connected in series in the load circuit through a resistance R upon opening of said circuit breaker. llleans is provided whereby upon opening of circuit breaker 2 the current through winding 7 is rendered proportional to the resistance of the load circuit. Such means comprises an adjustable resistance R and auxiliary contacts 9 associated with circuit breaker 2, such contacts being arranged to close upon opening of circuit breaker 2 and being adapted to include resistance R in shunt with the load 1. For purposes hereinafter set forth. resistance R is of relatively high value while'resistance R is of relatively low value.

The function and operation of the aforedescribed circuit breaker system will now be more fully described. Under normal current conditions in the load circuit relay 5 is in closed position and establishes an energizing circuit for winding 3 extending from line L through switch 4.- and said relay, by conductor 10 to and through the winding 3 to line L. With circuit breaker 2 in closed position the load circuit is completed and winding 6 is included in series in said circuit. Under abnormal current conditions in the load circuit winding 6 acts to open relay 5 and the aforedcscribed energizing circuit for winding 3 is interrupted to permit opening of circuit breaker 2. Immediately upon opening of circuit breaker 2, winding 7 is energized to hold relay 5 in open position, the energizing circuit for said winding, extending from line I to and through the series winding 6, by conductor 11 through resistance R, by conductor 12 through winding 7, by conductor 13 through the load 1 to line L. Also, immediately upon opening of circuit breaker 2, circuit is established from line L through resistance R as already traced,through aux- IOU v of current passes therethrough which divided between the circuit including winding 7 and load 1 and the circuit extending through contacts 9 and resistance IF. The amount of current passing through said circuits will be inversely proportional to the value of the re -ance ot the load circuit and winding 7 with respect to the value at resistance R Thus, as long as tle res'Jtance of the load circuit is relatively low a relatively large part of the current will pass through win dine; T to maintain relay 5 "a open position. However, soon as the resistance of the load circuit is increased. more current passes through the ciruit including resistance It until a point is reached where toe resistance of the load circuit has increased to a predetermined value and coil 7 will not have suilicient current passing therethrough to retain relay 5 in open position. Relay 5 then closes against the retarding action of dash pot 8 to reestablish the aiorcdescribed energizing circuit for winding 2-3 of circuit brea er 2 for reclosure ot the latter. Thus. provision is made for interrupting the load circuit in case of a short-circuit or overload and for automatically reclosing the same upon removal of the short-circuit or overload.

In connection with the foregoing it should be noted that the at'oredescribed circuit breaker system will also act upon excessive voltage conditions in the supply circuit L L It is apparent that under such conditions winding 6 will efiect response of relay 5 for opening of circuit breaker 2 while winding 7 will function in the manner above described to prevent reclosure of relay 5 pending restoration of normal voltage conditions in the supply circuit.

Referring now to Fig. 2, the same illustrates a modification of the control system shown in Fig. 1. In this system an additional relay 15 is provided in the energizing circuit of the winding 3 and a winding 16 connected in the same manner as the winding 7 in Fig. 1 is provided for efi'ecting response of this relay. The system shown in this figure functions in substantially the same manner as the system shown in Fig. 1, the winding 6 serving to interrupt the energizing circuit of the winding 3 of the circuit breaker 2 under abnormal current conditions in the load circuit, and the winding 16 serving to etlcct response of relay 15 upon opening of the circuit breaker 2 to retain said relay in open position until the resistance in the load circuit has dropped to normal value.

What I claim and desire to secure by Letters Patent is:

1. In an automatic reclosing circuit breakor system wherein a circuit breaker is arranged to connect a source of current to a load circuit, in combination, a closing coil for said circuit breaker, an energizing circuit for said coil, a plurality of windings for controlling the energizing circuit of said coil, one being responsive to current conditions in said load circuit when said circuit breaker is closed and the other to be connected in series between said source and said load circuit upon opening of said circuit breaker, a relatively high resistance for limiting the current through said latter winding and a relatively low resistance to be connected in shunt with said latter winding and said load circuit upon opening of said circuit breaker.

2. In an automatic reclosing circuit breakcr system wherein a circuit breaker arranged to connect a source of current to a load circuit, in combination, a closing coil for said circuit breaker, an energizing circuit for said coil, a plurality of windings for controlling said energizing circuit, one being responsive to current conditions in said load circuit when said circuit breaker is closed and the other to be connected between said source and said load circuit upon opening of said circuit breaker, a relatively high resistance for limiting the current through said latter winding and a relatively low resistance, and contacts associated with said circuit breaker for connecting said low resistance in shunt with said latter winding and said load circuit upon opening of said circuit breaker.

3. In an automatic reclosing circuit break or system, in combination, a supply circuit. a load circuit, a circuit breaker for connecting said load circuit to said supply circuit, and means for effecting opening of said circuit breaker under abnormal current conditions in said load circuit and for effecting rcclosure thereof under given resistance conditions in said load circuit, said means including a relatively high resistance, a winding connected in shunt with said circuit breaker and in series with said resistance and a relatively low resistance to be connected in shunt with said winding and said load circuit upon opening of said circuit breaker.

In witness whereof, I have hereunto subscribed my name.

EDWIN V. SEEGER.

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