US2554510A

US2554510A - Drawout mechanism for compartmented circuit breakers

Info

Publication number: US2554510A
Application number: US696559A
Authority: US
Inventors: George W Spicer
Original assignee: ITE Circuit Breaker Co
Current assignee: ITE Circuit Breaker Co
Priority date: 1946-09-12
Filing date: 1946-09-12
Publication date: 1951-05-29
Anticipated expiration: 1968-05-29

Description

1 1951 G. w. SPICER I 2,554,510

DRAWOUT MECHANISM FOR COMPARTMENTED CIRCUIT BREAKERS Filed Sept. 12. 1946 5 Sheets-Sheet 1 INVENTOR. geong'ewsplcen ATTORNEYS May 29, 1951 DRAWOUT MECHANISM FOR COMPARTMENTED CIRCUIT BREAKERS Filed Sept. 12, 1946 5 Sheets-Sheet 2 INVENTOR. G eo o'e W. S

PICCP aal-Jvfi ATTORNEYS May 29, 1951 s. w. SPICER 2,554,510

DRAWOUT MECHANISM FOR COMPARTMENTED CIRCUIT BREAKERS Filed Sept. 12, 1946 5 Sheets-Sheet :s

INVENTOR. Oeono'e W. SPICGY BY W 15 ATTORNEYS May 29, 1951 G. W. SPICER DRAWOUT MECHANISM FOR COMPARTMENTED CIRCUIT BREAKERS Filed Sept. 12, 1946 5 Sheets-Sheet 4 INVENTOR. Oeonoe W. SPICGP 9 c3 MM WM ATTURNEYS y 29, 1951 G. w. SPICER 2,554,510

DRAWOUT MECHANISM FOR COMPARTMENTED CIRCUIT BREAKERS Filed Sept. 12, 1946 5 Sheets-Sheet 5 IN VEN TOR. Geopo'e W. SPICEYJ BY 3 I ATTORNEYS Patented May 29, 1951 DRAWOUT MECHANISM FOR COMPART- MENTED CIRCUIT BREAKERS George W. Spicer, Philadelphia, Pa., assignor to I. T. E. Circuit Breaker Company, Philadelphia, Pa., a corporation of Pennsylvania Application September 12, 1946, Serial No. 696,559

7 Claims. 21

My present invention relates to circuit breaker enclosures, and more specifically to racking mechanism arranged to facilitate the drawing out of circuit breakers from a circuit breaker housing in a switchboard.

Circuit breaker structures mounted on trucks in switchboard housings frequently must be moved to a test position wherein they are disconnected from the back connection studs within the housings without interfering with the operation of the remainder of the switchboard.

In practice, it has been found that a circuit breaker which must maintain substantially continuous service has been erroneously racked out and thus interrupted a line which is supposedly in service. This usually is the result of a misunderstanding between the operator in control of the service and a workman sent to rack out a circuit breaker for test. The circuit breaker is remote controlled.

Accordingly, I have provided an arrangement for so interlocking the circuit breaker with its racking mechanism that the racking mechanism cannot be operated unless the operator has first tripped the breaker. Thus, if the workman erroneously starts to rack out a circuit breaker, he will be unable to do so.

This also has the advantage that in racking a circuit breaker out of the operative position to the test position, it is done only when the circuit breaker is tripped so that current interruption will occur between movable contacts having an appropriate arc quencher and will not take place at the back connection studs which are not thus protected.

It is also desirable to provide means for moving the circuit breaker on its truck to the test position without opening the door of the compartment or housing, while nevertheless providing a clear indication when the circuit breaker has been moved to the test position.

Accordingly a primary object of my invention is the provision of novel racking mechanism for a truck mounted circuit breaker adapted to move the circuit breaker out of and into a compartment of a switchboard.

Another and important object of my invention is the provision of novel racking mechanism which can be operated from the front panel of the compartment without the necessity for opening the front panel and which is adapted to move the truck mounted circuit breaker from the operative position to the test position.

Still another object of my invention is the provision of novel means for indicating the position of the truck mounted circuit breaker in the compartment.

A further object of my invention is the provision of novel means for interlocking the racking mechanism with the circuit breaker itself so that the racking mechanism is operative only when the circuit breaker is in the tripped condition.

The foregoing and many other objects of my invention will become apparent in the following description and drawings in which Figure 1 is a side view showing the arrangement of my novel racking mechanism on a truck mounted circuit breaker.

Figure 2 is a view in perspective partly broken away showing specifically the operating elements of my novel racking mechanism.

Figure 3 is a view corresponding to a portion of Figure 2 showing the operating details of my novel racking mechanism, and modified to eliminate nonessential details.

Figure 4 is a side view corresponding to a portion of Figure 1 showing the details of my novel racking mechanism when the circuit breaker truck is sufficiently within the compartment so that the circuit breaker is in operative position.

Figure 5 is a view corresponding to that of Figure a showing the position of the racking elements with the truck moved forward in the compartment so that the circuit breaker is in the test position.

Referring now to Figure 1, I have here shown a truck mounted circuit breaker iii of the type generally shown in Patent No. 2,355,075, issued August 8, 1944, in which the truck ll carries an insulated back panel ii on which the circuit breaker elements are mounted. Upper back connection stud I3 is connected to stationary circuit breaker contact [5. Lower back connection stud I5 is connected to the movable circuit breaker contact it. The circuit breaker is operated by any suitable mechanism such as that shown in the aforementioned Patent No. 2,355,075, issued August 8, 1944, and is so arranged that in the closed position of the circuit breaker, the bell crank I8 is connected by the linkage IT to the movable contact carrying member and is in the position shown in Figure 1. In the open position of the circuit breaker, the bell crank it of the movable contact member it has moved toward the left with respect to Figure l pulling link 20 along with it toward the left.

The circuit breaker racking mechanism indicated generally at 2! comprises a housing 22 secured to a front frame member 23 of the truck mechanism and rigidly braced with respect thereto. As shown in Figures 1 and 2, the housing 22 comprises a pair of

side panels

24, 24 top and

bottom panels

25 and 26 respectively, and inclined front panels 2i and 28. The housing 22 of the racking mechanism is so mounted on the front frame 23 of the truck that it registers with the door 36 (Fig. 2) of the front frame member 3i of the switchboard compartment.

When the racking mechanism in housing 22 is to be operated open, the door 3% is opened to provide access thereto. With the circuit breaker in the operative position, the racking mechanism in the housing 22 is recessed entirely with the front panel 3 I, as shown in the left hand compartment of Figure 2. When the truck I and the racking mechanism 2| in housing 22 are withdrawn to the test position, the entire housing 22 of the racking mechanism 2| projects out through the door 3B in frame member 3| as shown in the right hand compartment of Figure 2.

The racking mechanism comprises a shaft til rotatably mounted in appropriate bearings in the front frame member 23 of the truck Ii. Said shaft iii carries the racking disc ii keyed thereto in any suitable manner as by the key 32. Shaft iil also has keyed thereto in any suitable manner at each of its ends the crank elements M and so that these elements are rotatable with the shaft to. Shaft to also has mounted thereon the interlock disc 5%. The interlock disc Bil is not keyed to the shaft at but is rotatable thereon so that the shaft to may rotate even though the interlock disc 56 is held. Interlock disc 5i; is connected by pin iii to the link 28, which in turn is connected to the end It of movable contact arm [5 of the circuit breaker l0.

An interlock rod SE5 (Fig. 4) is provided in the lower part of racking housing 22 terminating in an interlock release button 6| accessible from the outside of the housing 22. Button 6| of interlock rod to is slidable longitudinally in bearing 63 secured to the lower portion of the front panel of housing 22. Button 6| is of smaller diameter than rod to so that the enlarged diameter of rod Ell bearing against the left hand side of the bearing 53, limits the movement of the interlock rod 6% toward the front of the housing.

The rear end of the interlock rod to is turned down at 65 and passes through an appropriate bearing es in flanged platefil carried by the front frame 23 of the truck (Figs. 1, 4 and 5). A compression spring 58 is carried between plate ti and the rear end of the enlarged diameter of rod 66 biases the rod to toward the right with respect to Figure 4 or toward the front of the housing. Rod (it carries adjacent its rear end a bar ll! which engages the electrical switch ll secured to flange '52 of lower panel 25 of housing 22.

Racking disc 4| is provided with a locking recess 3!) as shown in Figure 4 into which the bolt 8i fits when the circuit breaker and its truck are entirely within the housing with the circuit breaker back connection studs connected to the appropriate back connection elements of the compartment. Consequently with bolt-3i locked in the racking disc 4|, racking disc 4| cannot be rotated.

Racking disc 4| is provided with a plurality of peripheral holes 8282a into which a bar may be inserted in order to rotate the disc 4| and thus operate the racking mechanism. However, prior to any attempt at rotating the disc 4 it is necessary to remove the bolt 8| from the recess til in the racking disc 4|. Bolt 8| as shown in Figures 2, 3 and 4 is connected by pin 83 to the bell crank 4 lever 84, which bell crank lever 84 is pivoted at 85 on a portion of the front frame 23 of the truck II.

The lower leg of bell crank 84 is connected by pin 85 to the rod 6b. The connection at

pins

83 and 86 are appropriately slotted as shown to permit bell crank 84 to rotate readily about its pivot 85 without binding. When it is now desired to rack out the circuit breaker truck H to the test position, the door 35 is opened and a racking bar is inserted in the opening 82.

Button BI is pushed in toward the left with respect to Figure 4. This operates the electrical switch H in order to operate any control, indicating, or locking circuits which should be thrown into operation when the truck of the particular circuit breaker is being racked to test position. At the same time pushing in of button 6| causes a clockwise rotation of bell crank 84 to pull down bolt 8| and thus pull same out of the recess 89 of racking disc 4|, thus freeing rackingdisc M for operation.

However, operation of the racking disc 4| to rack out the circuit breaker should not occur unless the circuit breaker itself is in the tripped position so that the back connection studs will not be required to interrupt heavy current. For this purpose, therefore, the interlock disc 58 which is connected to the link 29 is provided on the shaft 4|). Interlock disc to is so arranged that when the circuit breaker is in the open position. link 26- has pulled interlock disc 5!] around to a position where the opening 88 thereof registers with the bolt 89. Bolt @9 is connected by pin to to bell crank lever 9i which is pivoted at 92 on the front frame 23 of the truck A lower leg of bell crank 8| is connected by pin 93 to the interlock rod 96. Here appropriate slots are provided at pins and $3 to prevent binding of the bell crank lever When the button 6| is pushed in, then in addition to rotating bell crank 34 clockwise to pull down bolt 8|, the bell crank lever 9| is rotated clockwise to push up the bolt 89. Bolt 89 is pushed up against the periphery of the interlock disc 59.

If the circuit breaker is in the open position, then interlock disc 5i! is in the position where opening 88 thereof registers with bolt 89 and bolt 39 may freely enter opening 88 at the same time that the bolt 8| is withdrawn from opening 88 of racking disc. If, however, the circuit breaker is in the closed position then the opening 8t and interlock disc 50 is out of registry with the bolt 89 and bolt 89 cannot move up.

Since bolt 89 cannot move up, this prevents the rod 66 and the button 6| from being pushed in and thus prevents withdrawal of bolt 8| from the racking disc 4|. Consequently, the racking disc 4| cannot be freed to operate unless the circuit breaker is in the open position.

Assuming now that the circuit breaker is properly in the open position so that bolt 89 may enter opening 38 in interlock disc 50, then insertion of a racking bar in opening 82 of racking disc 4| and pushing in of button 6| will remove the bolt 8| from the opening 8|) of the racking disc 5| and at the same time push the bolt 83 into opening 88 of the interlock disc 50, thus locking the circuit breaker in open position.

The racking bar (not shown) is pulled up to rotate the racking disc 4| in a counter-clockwise direction, (as seen in Figures 1, 2, 3, 4, and 5). Rotation of the racking disc 4| causes the shaft All to rotate and the roller 95 to rise in the slot 91 of the block 96. Since the block 96 is fastened securely to the frame of the cubicle, rotation of the crank element 45 causes the truck II and circuit breaker H3, mounted thereon, to move forward. Similarly, element 44 causes roller 95 to rise in a similar slot of a block (not shown) at the left (Figure 3). When the racking bar has reached the upper limit of the housing 22 and is prevented from further rotation by the upper inclined front panel 21 it must be re-inserted in a similar hole 82a and a second rotation of the racking disc 4| is made. Before the racking bar has reached the inclined front panel for the second time the bolt 8| biased upwardly by compression spring 68 through ball crank 84 will enter the hole 81 which will lock the circuit breaker III in the test position. To completely remove the breaker from the cubicle the release button 6| must be pushed again to remove the bolt 8| from the hole 8'1 and the racking bar moved up to complete the second rotation of the racking disc 4| at which time the locking bolt 8| enters the hole 81a. in the racking disc 4| and locks the breaker ID in the position in which its studs l3 and I5 are disconnected from the bus bar. The entire housing 22 of the racking device 2| then emerges through the door 38 in frame member 3| and the full emergence of the housing 22 to the position shown at the right hand compartment of Figure 2 indicates that the. circuit breaker has been racked to the open position.

In returning the circuit breaker to operating position, the racking mechanism first rendered operative by operation of button BI, is racked in the reverse direction, i. e., by inserting the racking bar in opening 82 and pulling downwardly.

The positions of the racking elements of the circuit breaker structure when the circuit breaker has been racked out are shown in Figure 5. Here the additional opening 87a in the racking disc 4| is moved opposite the bolt 6| so that release of the button 6| will permit spring 63 to drive rod 60 back to the right and thus force the bolt 8| back into locking relation with the racking disc 4| while at the same time withdrawing bolt 89 from looking relation with the interlock disc 50.

Since interlock disc 50 is now released, the circuit breaker may now be operated in the test position. In order to operate the circuit breaker between its open and closed condition when in its test position, a rod I is provided connected to the tripping mechanism of the circuit breaker and operable as shown from the front of the compartment panel. Any attempt to rack the circuit breaker back into operative position without first pushing in the button 6| would result in failure since the racking disc 4| is locked by the bolt 8| having entered the hole 81a, and the circuit breaker Ill cannot be racked to the operative position except by the rotations of the racking disc 4| This will prevent accidental racking of the circuit breaker while the contacts are closed. In order to reestablish the circuit breaker in the operative position once more, button 6| must be pushed in and as before described, the bolt 8| cannot be removed from opening 87a of racking disc 4| unless the bolt 89 is free to enter opening 88 of interlock disc as; and this can occur only when the circuit breaker is in the open circuit position.

Consequently the circuit breaker can be pushed back into operative position only when the contacts thereof are open. When it is pushed back into the operative position, roller 95 bearing against the block 95 causes the crank 44 to rotate back from the position of Figure to the position of Figure 4 so that the racking elements are re- 6 turned to operative position for moving the circuit breaker out once more.

As will now be clear from the above, the essence of this invention is its fool proof safety feature. In power station operation it is undesirable to have some circuits interrupted for any reason, except in extreme cases.

Therefore, it is conceivable that in certain cases some circuits would never be shut down and that careless or inadvertent manipulation of the breakers protecting such circuits could cause in-- jury or serious damage. With the present invention, however, such a contingency is virtually impossible.

If an authorized power station employee gave instruction for servicing a particular circuit breaker and the operator should select the wrong breaker he would be unable to withdraw the wrong breaker since its racking disc 4| would be locked by the bolt 8| being entered in the recess 88. I

This he would not be able to free by pushing the release button 6| since that member cannot be actuated unless the interlock disc 50 is properly rotated to present the opening 88 to the interlock bolt 89, and the interlock disc 59 cannot be rotated except b tripping open the breaker contacts.

It is obvious therefore that if operators follow the invariable rule of never tripping a circuit breaker, they can never inadvertently remove the wrong circuit breaker from a line that is alive or in service.

In the event that it is desired to remove the circuit breaker entirely after it has been racked out to test position, this can be accomplished because in the final test position the pin 95 (Figure 3) has been moved down to a position in the slot 9?! below the surface of member 96 and is then free to be entirely withdrawn, together with the circuit breaker, from the housing.

In the foregoing I have described my invention solely in connection with a specific illustrative embodiment thereof. Since many variations and modifications of my invention should now be obvious to those skilled in the art, I prefer to be bound not by the disclosures herein contained but only by the appended claims.

I claim:

1. In a switch gear mechanism, a truck mounted circuit breaker having an operative and a test position and having an open and a closed condition, a compartment for said circuit breaker having a front panel, a racking mechanism comprising a racking disk having a lock, means for operating said racking mechanism from said front panel for racking said breaker between its operating and test positions, and. means controlled by said circuit breaker for rendering said racking mechanism ineffective to rack said breaker from operating to test position while said circuit breaker is in closed condition, comprising a disk, a member connected to said circuit breaker movable contact at one end and to said disk at the other end and a connection from said disk to said lock for operating said lock to lock said racking disk when said circuit breaker is in closed position.

2. In a switch gear mechanism, a truck mounted circuit breaker having an operative and a test position and having an open and a closed condition, a compartment for said circuit breaker having a front panel, a racking mechanism comprising a racking disk having a lock, means for operating said racking mechanism from said front panel for racking said breaker between,

its operating and test positions, means for rendering said racking mechanism ineffective to. rack said breaker from operating to test position while said circuit breaker is in closed condition comprising means cooperating withsaid lock on said racking disk when said circuit breaker is inclosed position, said racking mechanism having a lock for preventing operation thereof while said cire u it breaker is closed, and manually operable zn eans for removing said lock operable only when said circuit breaker is in its open position, manually operable means including a disk on said racking mechanism and a second disk, each of said disks having recesses, individual bolts for said recess, said bolts being controlled by said manual means, the bolt for the recess ofsaid second disk preventing the removal of the bolt from said racking mechanism disk except when said circuit breaker is in open condition.

3;. In a switch gear mechanism, a truck mounted circuit breaker having an operative and a test position and having an open and a closed condition, a compartment for said circuit breaker having a front panel, a racking mechanism compri 'ng a racking disk having a lock, means for operating said racking mechanism from said frontpanel for racking said breaker between its operating and test positions, means for rendering said raoking mechanism ineffecti 'le to rack said breaker from operating to test positionwhile said circuit breaker. is in closed condition comprising means; cooperating with said lock on said racking disk when said circuit-breaker is in closed position, said racking mechanism having a lock for preyenting operation thereof while said cir- Quit breaker is closed, and manua ly operable means for removing said lock operable only when said circuit breaker is in its open position, said manually operable means including a disk on said racking mechanism and a second disk, each of said disks having recesses, individual bolts for said recess, said bolts being controlled by said manual means, and a positive connection from said circuit breaker to said second disk for rotating said disk to a position in which the recess thereof is opposite bolt when said circuit breaker is in open position.

4. In a switch gear mechanism, a truck mounted circuit breaker having an operative and a test position and having an open and a closed condition, a compartment for sa d circuit breaker having a front panel, a racking nechanism comprising a racking disk having a lock, means for operating said racking mechanism from said front panel for racking said breaker between its operating and test positions, means for rendering said racking mechanism ineffective to rack said breaker from operating to test position while said circuit breaker is in closed condition com prising means cooperating with said lock on said racking disk when said circuit breaker is in closed position, said racking mechanism having a lock for preventing operation thereof while said circuit breaker is closed, and manually operable means for removing lock operable only when said circuit breaker is in its open posit-ion, said manually operable means including a disk on said racking mechanism and a second disk, each of said disks having recesses, individual bolts for said recess, said bolts being controlled by said manual means, and a positive connection from said circuit breaker to said second disk for rotating said disk to a position in which the recess thereof is opposite its bolt when said circuit 8 breaker is in open position, said first bolt being prevented from leaving its recess except when said second bolt enters the recess of said second disk. 5.In a circuit breaker having a pair of cooperable'contacts having an engaged and a disengaged position, and having an operative and test "position, back connection studs connected to "said cooperable contacts; a cubicle for said circuit breaker having side and back walls and a front door" pane1 through which said circuit breaker is ra ckabie into and out of its cubicle; a racking mechanism having a lock; means for operating said racking mechanism to operate said circuit breaker between an operating position, in which said back connection studs are in position for electrical connection in the power circuit being protected by said circuit breaker and a test; position in which said back connection studs are in the position of disengagement from the power circuit; a connection from one of said cooperable contacts to said lock on said racking mechanism for locking said racking mechanism ag inst operation of said circuit breaker with respect to its cubicle when said pair of 00+ operable contacts are in engagement, and a member accessible from outside said front door panel for operating said lock to release said racking mechanism solely when said pair of co operable contacts are disengaged from each other, said front panel of said cubicle having an opening through which saidracking mechanism is accessible bysaid first means to permit/racking of said circuit breaker to its test position, part of said racking mechanism protruding through said opening in said front door panel when said circuit breaker is in its test position.

6. In a circuit breaker having a pair of cooperable contacts having an engaged and a disengaged position, and having an operative and test position, back conn ction studs connected to said cocperable contacts; a cubicle for said circuit breaker having side and back walls and a front door panel through which said circuit breaker is rackable into and out of its cubicle; a racking mechanism having a lock; means for operating said racking mechanism to operate said circuit breaker between an operating posi tion, in which said back connection studs are in position for electrical connection in the power circuit being protected. by said circuit breaker, and a test position in which said back connection-studs are in the position of disengagement from the power circuit; a connection from one of said cooperable contacts to said lock on said racking mechanism for locking said racking mechanism against operation of said circuit breaker with respect to its cubicle when said pair ofcooperable contacts are in engagement, and

a member accessible from outside said front door panel' for operating said lock to release said racki" g mechanism solely when said pair of coop ble contacts are disengaged from each other, said front panel of said cubicle having an opening through which said racking mechanism is accessible by said first means to permit racking of said circuit breaker to its test position, part of said racking mechanism protruding through said opening in said front door panel when said circuitbreaker is in its .test position, and a second member extending through said front door panel connected to said cooperable contacts for operating said .cooperable contacts to disengaged position.

7; In'acircuit breaker having a pair-of co- *9 operable contacts having an engaged and a disengaged position, and having an operative and test position; back connection studs connected to said cooperable contacts; a cubicle for said circuit breaker having side and back walls and a front door panel through which said circuit breaker is rackable into and out of its cubicle; a racking mechanism having a lock means for operating said racking mechanism between an operating position, in which said back connection studs are in position for electrical connection in the power circuit being protected by said circuit breaker, and a test position in which said back connection studs are in the position of disengagement from the power circuit, a physical connection from one of said cooperable contacts to said racking mechanism for preventing operation of said racking mechanism when said pair of cooperable contacts are in engagement and for permitting release of said lock to permit REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,258,150 Scott Oct. 7, 1941 2,363,364 Rugg Nov. 21, 1944