US2342821A - Reclosing circuit breaker system - Google Patents

Description

Feb. 29, 1944. M E REAGAN 2,342,821

RECLOSING CIRCUIT BREAKER SYSTEM Original Filed Sept. 3, i938 wnmzsszs; v INVENTOR Mal/rice E Reagan.

Patented Feb. 29, 1944 BECLOSING CIRCUIT BREAKER SYSTEM Maurice E. Reagan, Forest Hills, Pa., assignor to 7 Westinghouse Electric 42 Manufacturing Company, East Pittsburgh, Pa., a corporation of Pennsylvania Original application September 3, 1938, Serial No.

228,331, now Patent No. 2,264,712, dated December 2, 1941. Divided and this application November 13, 1940, Serial No. 365,502

8 Claims.

The invention relates to circuit interrupters in general and more particularly to operating means for circuit breakers.

The present application is a division of my copending application entitled Circuit interrupting apparatus, Serial No. 228,331, filed Septemher 3, 1938, assigned to Westinghouse Electric & Manufacturing Company and which is now Patent No. 2,264,712, granted December 2, 1941.

Circuit breakers are usually provided with operating means including closing means, latching means or toggle devices for maintaining the breaker closed, and circuits for causing opening or closing of the breaker.

It is very important that the breaker closing means remain energized for a sufficient length of time to insure that the breaker is actuated to the fully closed position as otherwise the breaker may immediately return to open position. Under the last-mentioned condition the breaker mechanism will continue to try to close the breaker as long as the closing control switch is held in closed position. It is desirable, therefore, to provide some means for ensuring that the closing means will remain energized for a sufiicient length of time to move the circuit breaker to the fully closed position.

An object of the invention is the provision of a circuit breaker and operating means therefor which will normally ensure that the circuit breaker is moved to the completely closed position before the operating means ceases to function.

Another object of the invention is the provision of a circuit breaker and operating means therefor: which embodies a means for ensuring that the closing means will remain energized for a sufficient length of time to normally effect complete closing of the circuit breaker.

In accordance with the invention there is provided a capacitor or other electrical device which is energized on opening of the circuit breaker. When the breaker is being closed, the energy stored in the capacitor or device is discharged through a circuit which maintains the closing means energized until the circuit breaker has been moved to the fully closed position.

The novel features that are considered characteristic of my invention are set forth with particularity in the appended claims. The invention itself, however, both as to its organization and its method of operation, together with additional objects and advantages thereof will best be understood from the following description of a specific embodiment when read in connection with the accompanying drawing, in which the single figure is a diagrammatic view showing an embodiment of the invention by the operation of which the complete closing of a circuit breaker is assured.

The apparatus shown in the drawing comprises a circuit interrupter 1 of the conventional construction equipped with a main contactor 9 and a latching arrangement H whereby it is latched in the closed position. Energy for actuating the circuit interrupter l is derived from a pair of direct current supply conductors l3 and 15 which may be supplied in any suitable manner as from a direct current source or through rectifiers from an alternating current source. The circuit interrupter is closed by the excitation of a solenoid ll to the core IQ of which the actuating bar 2| for the interrupter is attached. The exciting coil 23 of the solenoid H, which is customarily designated as the closing coil of the circuit breaker, is connected across the direct current supply conductors l3 and I5 through the contactor 25 of a closing relay 2! which is energized when the circuit breaker is to be closed.

For controlling closing of the interrupter, a control switch 29 is provided. The latter may be latched in the closed position after being manually moved to closed position, and opens under the action of gravit'y when after a closing operation, its latch 3| is released. It may be reset manually.

The closing control switch 29 maintains a circuit through the coil 33 of the closing relay 2'! closed and the latter in energized condition. When the latch 3| of the control switch is released and the switch falls out, the closing relay would ordinarily be deenergized opening its contactor 25. If the circuit interrupter mechanism 1 has not been latched in closed position at the time that the control switch is opened, the circuit breaker would be opened because its associated closing coil 23 is deenergized.

To make certain that the circuit interrupter is moved to the fully closed position and latched before the termination of a closing operation there is provided, in accordance with theinvention, a capacitor 35 which is charged quickly when the circuit interrupter 1 is opened and which slowly discharges through a resistor 31 and the exciting coil 33 of the closing relay 2! during closing of the circuit interrupter. The closing relay 2! ismaintained energized by the discharge current from the capacitor 35 after the closing control switch 29 reopens and, therefore, at this time, the coil 23 of the circuit interrupter closdisposed in relay.

in; means I! is maintained excitedand the circuit breaker. it it is not yet closed, continues to close in spite of the dropping out of the closing control switch, or opening of the auxiliary switch onthe circuit breaker, which auxiliary switch is the control circuit of the closing Th operational the apparatus is briefly as follows: immediately the circuit breaker opens, the capacitor 35 is quickly charged in a circuit which extends from the positive supply conductor i3 through a conductor 39, a rectifier H, the capacitor 35, a conductor IS, an auxiliary switch 45 which is closed when the circuit breaker opens, a conductor to the negative supply conductor l5. The rectifier 4i is provided in circuit with the capacitor 35 to prevent its discharge through any circuits or portions circuits which happen to be connected to the direct current supply 13- i5. It is preferably of the dry type such as a copper-oxide rectifier. It is to be noted that in the charging circuit just traced there are no resistances other than the resistance of the rectifier 4i and-of the conductors 39, 43 and 41. Because of this situation, the time constant of the circuit is small and the capacitor 35 charges quickly.

When th circuit interrupter 1 opens, a circuit is prepared through the exciting coil 33 of the closing relay 21. The circuit extends from the positive supply conductor I3 through a conductor 49, the-lowest auxiliary switch 5| of the circuit interrupter which is closed when thecircuit breaker opens, a conductor. 53, the closing control switch 29, another dry rectifier 55, the exciting coil 33 of the closing relay 21, the central auxiliary switch 45 of the circuit interrupter,

the conductor 41 to the negative supply-conduc- I able the circuit interrupter 1 to completely close.

After the interrupter is latched in the closed position, the capacitor 35 is discharged through the auxiliary coil 33, the relay 21 opens, and the syetem continues to operate in the normalmanher. The closing control switch 23 may be'cloeed'at any convenient time by the operator. I! the fault producing the actuation of the circuit breaker happens to be permanent, the circuit interrupter 1 is again reopened.

The upper auxiliary switch 89 of the circuit interrupter is provided for the purpose of Preventing undesired operation oi! the closing relay 21 by reason of current flowin a circuit through exciting coil 33 of the relay and through the discharge resistor 31 which liappens to be closed by mere coincidence when the interrupter 1 is opened. Th circuit extends from the positive supply conductor i3 through the conductor 33, the rectifier 4|, the -resistor 31, the rectifier 53, the rectifier 65, the exciting coil 33 of'the closing relay 21, the-central auxiliary switch 45 of the circuit breaker, the conductor 41 to the negative line conductor 15. The operation of the relay 21 is prevented because the exciting coil 33' is short circuited by the upper auxiliary switch 69 of the circuit interrupter and, therefore, diverts the current flow from the closing relay coil.

The function of' the rectifiers 53, 55 and 55 is the same as that of the rectifier H to prevent the undesired discharge of the capacitor 35 through extraneous circuits. For example, .the rectifier 55 in series with the closing control contactor 29 prevents the discharge of the capacitor 35 in a circuit extending through the conductor 39, the rectifier M, the capacitor 35, the exciting coil 33 of the closing relay 21, the closing control tor l5. To close the circuit breaker, the control 5 switch 23 is manually closed. This completes the prepared circuit just described efiecting energization of the closing relay 21. .The closing relayj 21 closes'its contactor 25 causing energization of the closing means l1. Since the electromagnetic action involved in the excitation of the closing relay 21 is slow compared to the time constant of the charging circuit for the capaciswitch 29, the lowest auxiliary switch 51 or the circuit interrupter, the conductor 49 and the por- -tion of the positive line conductor l3 connecting the conductors 39 and 49.

Although I have shown and described one embodiment of the invention, I amfully aware that tor 35,-the capacitor has time to charge substantially before the relay is actuated.

'On the actuation of the closing relay 21 its contactor 25 is closed and closes the circuit through the exciting co?l 23 of. the closing means l1, and also a v 'cir cuit "through the latching coil 51 oithef'c losir control switch 29-. T-helatter circuit extends the positive line conductor l3 through the'col'idlitipqjf 39, the contactor- 25 of the closing relay,;the'latching coil 51, a conductor 59- to-the negative line conductor 15. The latch 3i :is, therefore, released simultaneously with the energiza-tion of" the closing means I1 and both are operated together. The 'circuit interrupter 1, however, requires some time for complete operation, since it must be latched in the closed position. -To provide the necessary time,

the capacitor 35 is now discharged through the exciting coil 33' of the closing relay 21. The dis chargecircuit for the 'capacitor35 arte'nds from its left-hand plate 6i through thedischarge resistor 31, a third rectifier 53, a fourth rectifier i 55, theexcitiug coil 33 of the' closing relay 21,

the conductor 43 to the right-hand plate 61 of the capacitor. The resistor 31 is of such magnitude that the current flow through the exciting coil 33 of the auxiliary relay 21 continues at a substantialrvalue for a long enough time to enmany modifications thereof are possible. My in- .vention, therefore, is not to be restricted except insofar as is necessitated by the prior art and by the spirit of the appended claims.

I claim as my invention:

1. In combination, a circuit breaker, operating means which is energized to cause closin of said breaker and which is deenergized upon closing of said breaker, charge storing means, means actuated upon opening of said breaker for charging said charge storing means and a path including said operating means for discharging said charge storing means to maintain said operating means energized for a suificiently long time to completely close said breaker.

2.. In combination, a circuit breaker, operating means, a circuit for energizing said operating means to cause closing of said breaker, said circuit being opened upon closing of said breaker; charge storing means, means actuated upon opening of said breaker for charging said charge storing means to a substantial potential in an 1 interval of time that is short compared to the 3. In combination, a circuit breaker, operating means therefor, a circuit for energizing said operating means to cause closing of said breaker, said circuit being opened upon closing of said breaker, charge storing means, means actuated upon opening of said breaker for charging said charge storing means to a substantial potential in an interval or time that is short compared to the time required for said breaker to carry through one complete closing operation, a path including said operating means for discharging said charge storing means, said path being of such character and said potential being of such magnitude that said operating means is maintained energized by the discharge sufliciently long to completely close said breaker, and means for preventing the discharge of said capacitor through portions 01' said energizing circuit.

4. In combination, a circuit breaker having means for latching it in the closed position, operating means and a circuit for energizing said operating means to cause closing of said breaker, said circuit being opened upon closing of said breaker, charge storing means, means actuated upon opening of said breaker for charging said charge storing means to a substantial potential in an interval or time that is short compared to the time required for said breaker to carry through one complete closing and latching operation, and a path including said operating means for discharging said charge storing means, said path being of such character and said potential being of such magnitude that said operating means is maintained energized by the discharge sufliciently long to cause said breaker to be moved to the fully closed and latched position.

5. In combination, a circuit breaker, means operable to cause opening 01' said breaker, closing means for closing said breaker, an energy storing device, means operable upon opening of said breaker for storing energy in said device, and means for discharging the energy stored in said device during a closing operation to cause said closing means to remain energized a sufficient length 01' time to completely close said breaker.

6. In combination, a circuit breaker, operating means therefor including closing means for closing the breaker, a closing relay having contacts and an operated winding operable when energized to close the relay contacts and thereby cause said closing means to close the breaker, a source of electric energy, a control circuit including a pair of contro1 contacts operable when closed to cause energization of said relay operating winding by said source of energy, additional circuit means including an electrical energy storage device independent of said closing means automatically operable during a closing operation of the breaker to maintain said relay operating winding energized independently of the control circuit and for a sufficient length of time to normally cause complete breaking of the breaker.

7. In combination, a circuit breaker, operating means therefor including closing means for closing the breaker, a source of electric energy, a closing relay having contacts and an operating coil for closing said contacts to thereby energize said closing means, a control circuit having a pair of control contacts operable when closed to effect energization of said relay operating winding by said source of energy to cause said closing means to close the relay contacts and thereby move the breaker toward closed position, additional circuit means including an electrical energy storage device independent of said closing means automatically operable during a closing operation of the breaker to maintain said relay operating winding energized independently of said control circuit and for a sufficient length of time to normally cause complete closing of said breaker.

8. In combination, a circuit breaker, operating means therefor including closing means for closing said breaker, a source of electrical energy, a closing control device operable when energized to close an energizing circuit for said closing means, a control circuit including control contacts operable when closed to energize said device fromsaid source to cause energization of said closing means, said control circuit including auxiliary contacts on said breaker which are open when said breaker is in closed position to deenergize said device and means including an electrical energy storage device independent of said closing means and said closing control device automatically operable during closing operation 01. the breaker to maintain said closing control device independently of said source for a predetermined length of time sufiicient to normally effect complete closing of the breaker.

MAURICE E. REAGAN.

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