US2123256A - Circuit switching device - Google Patents

Description

y 12, 1938. R. R. PITTMAN ET AL 2,123,256

CIRCUIT SWITCHING DEVICE Filed May 24, 1934 5 Sheets-Sheet 1 INVENTORS 9 4w. Zfiima,

ATTORNEY July 12', 1938. R. R. PITTMAN ET AL 2,123,256

CIRCUIT SWITCHING DEVICE W 6'. 6011.104 ATTORNEY y 1938. R. R. PITTMAN ET AL. 2,123,256

CIRCUIT SWITCHING DEVICE Filed May 24, 1934 5 Sheets-Sheet 3 INVENTORS BY mam ATTORNEY Jilly 1938. R. R. PITTMAN ET AL 2,123,255

CIRCUIT SWI TCHING DEVICE Filed May 24, 1934 5 Sheets-Sheet 4 INVENTORS QL Z. W What BY M M M ATTORNEY y 1938. R. R. PITTMAN Ef AL 2,123,256

CIRCUIT SWITCHING DEVICE Filed May 24, 1934 5 Sheets-Sheet 5 INVENTORS 1 v "2- Bv Wax fl, I L L/WLA-LL Xi Wv/A/ ATTOFINEY Patented July 12, 1938 UNITED STATES CIRCUIT SWITCHING DEVICE Ralph R. Pittman and Carroll H. Walsh, Pine Bluff, Ark.

3 Claims.

This invention relates generally to switching equipment for electrical distribution and transmission line circuits, and particularly to a novel switching device in which is included a means for quickly extinguishing arcing faults on a connected circuit and reclosing the circuit, or disconnecting the circuit in the event the fault is of a permanent nature.

This application is a continuation in part of our copending application Serial No. 651,567,

filed January 13, 1933, now Patent 1,963,760 issued June 19, 1934, which discloses the same switching device described herein, except that it does not include the controlling mechanism for the device, or means for shunting the arc suppressing switch in each closed circuit position. These features of the invention are describe and claimed herein.

Among the objects of the present invention are a the provision of a switching device embodying, within a housing, a plurality of switches including a first and second main current may ing switch, an arc suppressing switch, a main and an auxiliary disconnecting switch, all operable by a single control member or rod, b the provision of an arrangement of switches in which an arc suppressing switch having a plurality of closed circuit positions is shunted by a current carrying switch in each closed position, 0 the provision of means combined with an arc suppressing switch embodied in the device for extinguishing an arcing fault on a connected circuit and subsequently reclosing the circuit in response to a unidirectional movement of the control member, :1 to provide a positive open circuit position for the device in which all of the elements of the arc suppressing switch are isolated from the circuit, e to provide a novel actuating means for the control rod of the device for establishing the relation to the connected circuit of the switches included in the device in response to the occurrence and duration of a fault on the circuit.

A further object is the provision of a high speed circuit reclosing device for reducing the outage time of electrical circuits subject to areing faults.

With the above and other objects in view which will appear from the description, our invention resides in the novel features of construction, arrangement and combination of the switches embodied in our device, and in the novel control means for the device, as hereinafter described and pointed out in the claims.

In the drawings:

PATENT OFFIQE Fig. 1 is a front elevational view showing the essential parts of the switching device, illustrated in a closed circuit position, and shown partly in section.

Fig. 2 is a sectional view of the arc suppressing switch of the device, taken approximately on the plane indicated by the line 2-2 in Fig. 1.

Fig. 3 is a fragmentary view of the contactcarrying bar of insulating material embodied in the device. 10

Fig. 4 is an elevational view of the switching contact arrangement of the device.

Figs, 5, 6, and '7 are views of the device and the controlling mechanism therefor. including a schematic diagram of the electrical connec- 15 tions, and showing the various positions which may be taken by the switches with respect to the connected circuit.

Referring now in detail to the drawings, and particularly to Fig. 1, l0 represents a housing for the device, only the portion necessary for supporting the switching assembly being shown for convenience. The substantially squareshaped hollow member ll, of any suitable material, is rigidly secured to the housing ill by 25 means of the cap screws M, the latter extending through the laterally-extending ears l3, which may be integral portions of the member H.

The insulating members 55 are rigidly secured 30 at the upper ends thereof to the inner sides of the opposing Walls of the member H by means of the bolts l2, and extend downwardly substantially normal to the plane of the top of the housing 18. The lower portions of the mem- I bers 55 are rigidly held in spaced relation by means of the insulating cross bars 42, and the cooperating cap screws 38. A pair of opposing blocks of insulating material 44 are supported by the members 55 by means of the bolts 31, the latter extending loosely through and normal to the plane of the members 55, and cooperating with tapped holes in the blocks 44, being held rigidly in place by the nuts 39. The springs 45 are arranged to urge the blocks 44 together, this movement being limited by the adjustment of nuts 39 on the bolts 31, with the result that the blocks 44 are free to move laterally outward from each other against the bias of the springs 45, but can not move inwardly toward each other beyond a distance controlled by the adjustment of bolts 31.

For convenience in guiding the movement of the movable member of the arc suppressing switch, the adjacent faces of the blocks 44 are made substantially in the shape of a flat bottom V. Extending through openings normal to the plane of the flat central portion .are the resiliently mounted contacts 48, of some suitable conducting material, biased toward each other by means of the springs ll, the latter being enclosed within the housing 45. To provide for a movement of the contacts 48, and for shunting the springs 41, the flexible conductors 49 are provided, having one end secured to the conduct ing members 34 by means of the screws 50. Two pairs of the contacts 58 are shown in this embodiment, the two contacts of each pair being I positioned in axial relation with the axis of one pair spaced vertically from that of the other.

The conducting members 3 are rigidly secured to the inner face of the insulating supports by means of the cap screws 35, and extend downwardly below the lower end of the insulating blocks 45. At this point the ends of the members '34 are bent inwardly one toward the other at substantially a right angle with the major portion thereof, the bent portions thus a-fiording a pair of surfaces adapted for cooperation with a pair of switch contacts.

Adapted for reciprocatory movement within the opposing blocks 44 is the movable member of the arc suppressing switch, shown more in detail in Fig. 2, and of such size and shape that it substantially fills the space between the blocks 44. This movable member includes a pair of insulating blocks is, arranged to laterally extend from a central block of insulating material 56, the three portions being rigidly held together by the bands 40 and the fastening screws All extending therethrough into the insulating member or control rod 33. A hollow portion within the assembly thus formed is provided for mounting the movable conducting contacts 52, which are located near the midpoint of the movable member and resiliently biased outwardly from each other by the spring 53. The flexible conductor 54 is for the purpose of shunting the spring 53. The contacts 52, together with the spring 53 and the conductor 54 thus form a bridging member for the arc suppressing switch, adapted to engage either the upper or lower pair of the contacts 48, or to move downwardly below the lower pair of the contacts 48, in response to a predetermined vertical movement of the control rod 33.

It will be seen that the springs 45 areconstantly urging the resiliently mounted blocks 44 toward the movable block 43. Upon the occurrence of an arc therebetween, the blocks 44 are urged laterally away from the movable block 43, the force of such action depending to a large extent upon the magnitude of the current in the arc. The width of the arc space is thus determined by a balance between the outward urging due to the arc and the inward bias of the springs. As a result, the interrupting ability of the arc suppressing switch tends to become independent of the current in the circuit interrupting arc.

We will now describe the means provided for inserting the arc suppressing switch in, andremoving it from, a circuit associated with the device. The entrance bushings l5, only partly shown, form an insulating housing of porcelain or other suitable material for the conductors l6 extending therethrough, and are rigidly supported b-ythe housing it in any suitable manner (not shown). Near the lower ends of the bushings 15 are mountedthe contractible conducting adapters l 7, each having an internal threaded opening for cooperating with threads on the lower portions of the conductors l5, and being locked in place by means of the set screws 18. The adapters H are further provided with an additional downwardly depending portion having opposing fiat parallel sides, and a pair of threaded openings are provided therein. The conducting contact fingers 20, illustrated more in detail in Fig. 4, are secured by the screws l9 extending into the above mentioned openings, and include a pair of opposing spaced conducting contact shoes 57 for cooperating with the springs 58. V The contact shoes 51 have inwardly curving portions at the lower extremities thereof to form a guide for the entrance of the cooperating contact 2!. The opposing faces of the contact shoes above the entrance flare are arranged to slope upwardly and outwardly from each other.

For cooperation with the contact fingers 2!], we provide a bar of insulating material 29 having the contact members 2i, of conducting material, rigidly attached to the bar 29 by the bolts 28. The contacts 25 arearranged to fit snugly within the space between the contact shoes 5?, and as shown in Fig. 4 are provided with an enlarged upper portion having a concave upper surface and inwardly and downwardly sloping opposing sides. It will be apparent that the bar 29 with the contacts 2i rigidly attached thereto is arranged to be removably supported by the bias of the springs 58 against the contact shoes 51, and that a downward movement of the bar 29 will cause the contacts '2! to be disengaged from their cooperating con tacts 25.

The contacts 2| are also provided with the inwardly disposed portions 27, which have a pair of upper horizontal surfaces adjacent the respective ends and near the top of thebar 2B.' 'To these surfaces are attached the upwardly disposed resilient auxiliary conducting contacts 35 by means of the screws 3i. These contacts 35 are arranged to engage the inwardly bent portion of the members 36 when the contacts 2i are seated within the contact shoes: 51. It will be seen that a downward movement of the bar 25 not only disengages the contacts 2! from the fingers 2'6, but also disengages the contacts 30 from their cooperating contact members 34. In addition to the upper surfaces of the inwardly extending portions of the contacts 2!, we have also provided similar flat surfaces near the bottom surface of the bar 29, for the purpose of rigidly securing thereto the downwardly disposed resilient conducting contacts 24 by means of the screws 25 and washers 26. For cooperating with the contacts 2 2, the conducting bar 22 is rigidly secured to the lower extremity of the rod 33 by the bolt 23, and is provided with a fiat upper side for engaging the contacts 24.

Obviously a downward movement of the operating rod 33 will cause the bar 22 to disengage the contacts 24. In addition to the flat portion for engaging the contacts 24, the bar 22 is provided with outwardly extending portions, for engaging, upon a predetermined downward movement of the'rod 33, the contacts 59, the latter being rigidly secured to outwardly and downwardly extending portions of the adapter H; or, upon a continued downward movement of the rod 33, to pass down- Wardly through the contacts 59.

The control rod 33 extends vertically through an opening near the midpoint of the bar 29, this opening being somewhat larger in section than the rod 33 to provide annular spacefifor the walls of the sleeve 32. A flanged upper portion of the sleeve '32 prevents its downward passage through the opening in the :bar 29, and the opening through the sleeve is somewhat larger than the cross-section of the rod 33, so that the latter may freely reciprocate through the sleeve 32. As shown in Fig. 3, the rod 33 and the sleeve 32 are preferablyrectangular in section to prevent rotation of the bar 29, and consequent contact misalignment. The collar'36, of any suitable material, is rigidly secured to the rod 33 adjacent the lower end of the movable portion of the arc suppressing switch, and is arranged, upon a definite downward movement of the rod 33, to engage the top flanged portion of the sleeve 32. By this means, a downward movement of the rod 33 urges the cross bar 29 in a downward direction, resulting in the disconnection of the contacts 2i from their cooperating contacts 20, and of the bar 22 from its cooperating contacts 59. Following such a movement, it will be seen that an upward move ment of the rod 33 will restore the contacts to the position indicated by the solid lines in Fig. 1.

In the initially closed position the current path through the device is into one of the conductors i6, through the bar 22 via the contacts 24, and to the other of the conductors It. A fractional part of the current may pass through the engaged contacts 30 and 34, and 52 and '48, but this in no way affects the operation of the device.

The broken lines in Fig. 1 illustrate the position of the movable members following a first downward movement. It will be seen that the bar 22 has moved away from the cooperating contacts 24, and into engagement with the contacts 59. The current path through the device is now from one conductor l6 through the contacts 59 and the bar 22 to the other conductor I 6.

Following a second downward movement of the control member 33, the collar 35 engages the upper flanged portion of the sleeve 32, thus urging in a downward direction the bar 29 and the contacts 2|. Upon a downward movement of the bar 29, the contacts 39 are moved downwardly away from their cooperating contact members 34, with the result that the arc suppressing switch is completely disconnected from the conductors It will be seen that our switching device comprises a main disconnecting switch including the cooperating members 20 and 2|, a first main current carrying switch including the cooperating members 22 and 24, a second main current carrying switch including the cooperating members 22 and 59, an auxiliary disconnecting switch including the cooperating members 39 and 34, and an arc suppressing switch including the cooperating members 48 and 52.

The relation of these switches to each other and to the connected circuit is schematically shown in Figs. 5, 6, and '7.

Fig. 5 shows the device in the initially closed position, in which the arc suppressing switch and the auxiliary disconnecting switch are in serial relation, these switches being shunted by the first main current carrying switch, the main disconnecting switch is in series with the group comprising the above three switches, and the second main current carrying switch is in the open position.

Fig. 6 shows the device following a first predetermined downward movement of the control member 33, in which the arc suppressing switch, the auxiliary disconnecting switch and the main disconnecting switch are serially related, this group being shunted by the second main current carrying switch, the first main current carrying switch being in the open position.

Fig. '7 shows the device following a second predetermined downward movement of the control member 33, in which all the elements of the arc suppressing switch, the auxiliary disconnecting switch, and the first main current carryingswitch are completely isolated from the normally live parts of the device, thus preventing any possibility of damage due to leakage or creepage currents over or through the elements of insulating material embodied in the arc suppressing switch.

Bearing in mind that electric line faults may be divided into two general classes, one due to transitory causes, as a lightning discharge, and

the other due to some non-disappearing cause,

as an insulation failure, we now describe the operation of the device in connection with the actuating means therefor, as illustrated in Figs. 5, 6, and 7.

In Fig. 5, the lines I99 and 19!, and H12 and H33, represent respectively the conductors of a supply and a load circuit, the switching device being interposed therebetween. The potential transformer 69 and the current transformer 6| are associated in the usual manner with the conductors I99 and 19!, and the voltage and current of the circuit are reproduced respectively therethrough in the voltage coil 66 and the current coil 6'! of the electro-responsive relay I94.

Upon the occurrence of a fault of a transitory nature, such as an arcing fault, on the load circuit, the movable member 58 of the relay I94 shunts the relay contacts 59 and I9, and thereby energizes the solenoid 16 from the auxiliary i 43 and 44, and thereby extinguishing the arcing fault. The downward movement of the control member 33 is continued following arc extinguishment until the stop 93, which is rigidly secured to the member 92 engages the latch member 99, at which point the bridging contacts 52 engage the lower pair of contacts 48 to reclose the circuit. The position of the switches following this operation is schematically illustrated in Fig. 6.

In case an arcing fault occurs on the load circuit when the switching device and mechanism are in the position illustrated by Fig. 6, the contacts 99 and of the relay I94 are again closed, thereby energizing the solenoid Tl through the conductor 12, the auxiliary switch contacts 99, H, and 98, the latch mechanism contacts 63, 5 3, and 65, and the conductor 14, causing a downward movement of the solenoid core 18, and a corresponding upward movement of the bridging contacts 52 to extinguish the arcing fault and to engage the latter contacts with the upper pair of contacts 48, thus restoring the device to the initially closed position illustrated by Fig. 5. The mechanism is in this manner arranged to actuate the arc suppressing switch from one closed position to the other in response to the occurrence and removal of abnormal electrical conditions on the load circuit.

If the fault is of a permanent nature, this condition is recognized by the actuating mechanism, and the switching device actuated to the fully open position and locked out. Assuming that such a fault occurs when the mechanism and switching device are in the position illustrated by Fig. 5, the relay I04 will cause the contacts 69 and I0 to'be shunted, thereby causing an upward movement of the member 92, as above described. If the fault is of such a. nature that it is not extinguished'before the contact member 82 engages the cooperating contacts 83 and 84, the solenoid 89 will be energized from the auxiliary power supply. In this case the latch member 90, to which the core of the solenoid 89 is pivoted, is rotated against the bias of the spring 9!, thus removing the latch member 90 from the path of the stop 93, and thereby permitting the unimpeded travel of the switching device to the fully open position shown in Fig. '7. It will be seen that the manual closing of the relay contacts 69 and 10 will restore the device to the initially closed position. I

Should a fault of a permanent nature occur when the device and mechanism are in the position illustrated by Fig. 6, a first downward movement of the member 92 will occur to restore the mechanism and device to the initial position shown by Fig. 5, and immediately thereafter the device will be actuated to the fully open position as above described.

The actuating means for the device is in this manner arranged to distinguish between faults of a transitory nature, and those of a permanent nature, and to cause the switching device to respond in accordance with the nature of the fault on the load circuit. Obviously any other mechanism embodying a suitable electo-responsive means in combination with an actuating means capable of supplying the above described movements may be used with the device.

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

1. A circuit switching device comprising elements constituting an arc suppressing switch, a r first and a second main current carrying switch, a main disconnecting switch, an auxiliary disconnecting switch, and a movable control member for operating said switches, said elements be ing so related that a predetermined longitudinal movement of the control member from a position in which all of said switches are closed except said second main current carrying switch effects the serial arrangement of said main disconnecting switch, said auxiliary disconnecting switch and said arc suppressing switch, opens said first main current carrying switch and closes said second main current carrying switch, said last named switch shunting said serial arrangement.

2. A circuit switching device comprising a housing, elements constituting an arc suppressing switch, a main disconnecting switch and a plurality of other switches all contained within said housing, a control member arranged to mechanically actuate all of the switches, said are suppressing switch having a plurality of closed circuit positions and an open circuit position, and means including elements common to said main disconnecting switch for shunting said arc suppressing switch in each of said closed circuit positions.

3. A circuit switching device comprising a housing, elements constituting an arc suppressing switch, a first main current carrying switch, a second main current carrying switch, an auxiliary disconnecting switch, and a main disconnecting switch all contained within said housing, a control member common to all of the switches for mechanically actuating said switches, said control member having a first position, a second position, and a third position, the elements of said switches being so combined that; in said first position said first main current carrying switch is in shunt relation with a serial arrangement of said arc suppressing and said auxiliary disconnecting switches, said main disconnecting switch is serially related to the last named three switches, and said second main current carrying switch is in the open position; in said second position said second main current carrying switch is in shunt relation with a serial arrangement of said are suppressing, said auxiliary disconnecting and said main disconnecting switches, and said first main current carrying switch is in the open position; in said third position said are suppressing switch is electrically isolated from the remainder of the switches.

RALPH R. 'PITTMAN. CARROLL H. WALSH.

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