US2787686A - Air puffer for circuit breakers - Google Patents

Description

April 2, 1957 G. A. WILSON AIR PURFER RoR CIRCUIT BREAKERS 2 Sheets-Sheet l Filed Aug. 31, 1953 Ap 2, 1957 G. A. WILSON AIR PUFFER FOR CIRCUIT BREAKERS 2 Sheeis-Sheet 2 Filed Augf 31, 1953 .DJ NE' IN VEN TOR. isoler/ //aa/v United States Patent O 1 2,787,686 AIR PUFFER FOR CIRCUIT BREAKERS George A. Wilson, Springfield, Pa., assignor to I-T-E Circuit Breaker Company, Philadelphia, Pa. Application August 31, 1953, Serial No. 377,527 8 Claims. (Ci. 20G- 148) My invention is related to air puffers for circuit breakers and is more particularly directed to a novel air puifer which operates on a pantograph principle requiring only the major parts of a vane and a casing.

Air puiers are used in coordination with circuit breakers in order to provide an auxiliary means to transfer the arc from the cooperating contacts toward and into the arc extinction means and may also be used to extinguish the arc. The air putfer device does not require stored energy for either its mechanical operation or source of air to be blown against the arc. The device is preferably pivotally connected to the movable contact arm or bridge in such a manner that the opening movement of the circuit breaker will supply the motivating force for its operation.

It will be noted that the air putter is primarily applicable to large circuit breakers which may require a blow out coil arrangement in order to lift and move the arc into the arc extinguishing means. However, with this type of breaker, the interruption of a relatively low magnitude of fault current may result in a magnitude of ampere turns for the blow out coil which is insufficient to create a large enough magnetic force to pull or force the arc off the cooperating contacts on to the arc horns and into the arc extinguishing means.

By providing an air puifer which is so constructed that it is operated both independent of the magnitude of the fault current being interrupted and does not require an auxiliary source of energy, it is possible to force the arc off the movable contacts even though the magnetic force created by the blow out coil is insuicient to properly move the arc. That is, by providing an arrangement in which the putter is operated directly from the movement of the bridge, its force and effect on the arc will be independent of the magnitude of the fault current and hence will operate equally well on the interruption of either a fault current or a short circuit current.

Heretofore, air putters have been constructed utilizing a piston-cylinder construction. However, this type of construction has many disadvantages which are overcome by the device of my invention. For example, in the prior art arrangement, the air movement was not generated close to the point of the arcing contacts and hence, its effectiveness on the arc is greatly reduced. Furthermore, this type of arrangement required a duct or passageway to guide the air flow from its point of generation to the arcing contacts thereby greatly reducing the force and effect of the air stream. Also, due to the fact that the piston-cylinder type of arrangement relied solely on straight-line motion, it was impossible to vary the rate of air flow which could be obtained from the air puifer device.

Since the primary function of the air putier is to lift the arc oii the arcing contacts, it is desirable to have maximum rate of air flow during the initial portion of the opening stroke. However, this sequence of air How is not possible with the prior art straight-line movement which supplies a steady air flow irrespective of the movement of the bridge.

A further disadvantage inherent in the straight-line movement of the piston-cylinder arrangement is that a portion of the air putter had to be positioned between the rear portion of the line terminals or studs and hence, might be conducive to an electrical failure to ground.

Furthermore, the prior art arrangement required a 2,787,686 Patented Apr. 2, 1957 multiplicity of parts which are relatively complex in construction and require extensive alteration to the circuit breaker mounting front.

With the novel air putter of my invention, I overcome all of the disadvantages of the prior art arrangement and obtain desirable operating characteristics which were not heretofore possible.

My novel air puier is comprised of a casing and a Vane movable thereby and therein. The casing is pivotally mounted on the bridge of the circuit breaker and one end of the vane is pivotally mounted on the lower terminal of the circuit breaker. In addition, the intermediate point of the vane is pivotally mounted on the casing. The casing is provided to a molding having parallel sides being substantially V-shaped with arcuate upper portions with one straight side on the arcuate end portions of the side being joined.

The arcuate connecting member between the arcuatel portions of the spaced parallel V-shaped sides of the casing is provided with an opening which forms the spout through which the air stream can be directed to the arcing contacts of the circuit breaker.

By adjusting the angle between the line formed by the common pivot of the casing on the bridge and the line formed by the common pivot between the casing and vane and the vane pivot on the lower terminal, the rate of air ow at any point within the opening stroke can be pre-adjusted.

ln addition to this feature, the pantograph arrangement will provide multiple motion so that the magnitude of angular velocity of the vane will be greater than the magnitude of angular velocity of the bridge. Hence, with my novel arrangement, it is not only possible to obtain more rapid movement of the vane, but it is possible to obtain both rapid movement of the vane and also to control its rate of movement at any point within the stroke. Thus, for example, when the above mentioned angle is an acute angle at the start of the opening stroke, then the rate of movement of the vane, and resulting air Bow, will be at a maximum at the start of the opening movement.

Thus, my novel apparatus can be adjusted to deliver the maximum rate of air ow at the beginning of the opening stroke which is the time when the air stream is most instrumental in moving the arc off the arcing contacts and is therefore the precise time within the opening stroke when maximum air ow is needed.

Further advantages are achieved with the pantograph system of my novel air pufler.

Since the casing is not restricted to straight line movement, the spout thereof can be initially positioned under the upper terminal. However, since it will follow a slightly arcuate path, the stream of air emanating therefrom is not trapped under the terminal and hence, is

blown into the area of the arcing contacts where it is most effective. That is, although the spout initially guides the air stream directly on the cooperating surfaces of the cooperating contacts, it Wili subsequently follow the arc out as the circuit breaker' is opened thereby exerting a force where it is most needed. f

The inherent structure of the above mentioned casing with the spout positioned on the top thereof, enables the pufer to generate a stream of air close to the arcing contacts thereby greatly increasing the efficiency of the air putter since the necessity of either providing guiding ducts or excess Wind friction to reduce the rate of flow is eiminated. Also, the fact that the stream of air is directly applied to the arcing contacts will insure a more prompt delivery thereof with a greater volume of air at a higher velocity.

In view of the fact that my novel air putter only requires two major parts, namely the vane and casing, the

unit has the advantage of both eXtreme simplicity and requires a minimum number of connecting points to the circuit breaker. Thus, my novel unit can be adapted to a standard circuit breaker with a minimum number of alterations thereof.

Accordingly, the air puller of my invention overcomes the disadvantages of the prior art and has many desirable features which were not heretofore obtainable.

An object of my invention is to provide an air puller for circuit breakers which is comprised of a vane and a casing which operate on a pantograph principle.

Another object of my invention is to provide a vanecasing arrangement which will generate a stream of air on the arcing contacts when the circuit breaker is opened.

Another object of my invention is to provide an air puller comprised of a vane and casing wherein the casing is pivotally mounted on the bridge. The vane is pivotaily mounted 011 the lower terminal and the vane and casing pivotally mounted to each other.

Still another object of my invention is to provide a pantograph type air puer having a spout which moves from under the upper terminal during the opening oper; tion of the circuit breaker.

Another object of my invention is to provide a relatively simple air puller which requires a minimum number of alterations to the circuit' breaker for the mounting thereon.

Another object of my invention is to provide an are transfer and extinguishing means for a circuit breaker which will generate a stream of air close to the arcing contacts.

Another object of my invention is to provide an are 'ransferring means which is operated by the motion of the bridge of the circuit breaker to provide a direct stream of air on the arc-ing contacts thereof.

A still further object of my invention is the adaption of a circuit breaker with a putter device which provides prompt delivery of a large volume of air at high velocity.

Still another object of my invention is to provide a 4)autograph air putlier which can be selectively mounted to obtain a predetermined rate of air ow.

Another object of my invention is to provide an air putter which can be selectively mounted to control the rate of air llow at any point within the opening stroke of the circuit breaker.

Another object of my invention is to provide an arc transferring means controlled and operated by the movement of the bridge of the circuit breaker in which the maximum rate of air llow will occur at the start of the opening movement of the bridge.

A still further object of my invention is to provide a construction for an air puller which can be mounted adjacent to the bridge of a circuit breaker and kept away from the rear of the upper and lower terminals of the circuit breaker.

These and other objects of my invention will be apparent, to those skilled in the art, from the following desciption when taken in connection with the drawings in which:

Figure l is a side view illustrating the position of my novel air puler when the bridge of the circuit breaker is in the closed position.

Figure 2 is a side view similar to Figure l illustrating the position of my novel air pulier when the bridge of the circuit breaker is in the open position.

Figure 3 is a top view of the air putter of my invention seen in Figures l and 2 illustrating the manner in which this unit can be connected and secured to the bridge of the circuit breaker.

In the illustration of my invention, I have shown a single pole circuit breaker it) having upper terminal 11 and lower terminal 12. A stationary contact 13 is electrically connected to the upper terminal 11 and the bridge 14 is pivotally connected at pin 15 to the lower terminal 12. The bridge 14 is provided with a movable contact and cor ed of two parallel sides i7 and 1S, which have a tf-shaped configuration with an arcuate top sur face.

Left hand sides of the wall 17 and 18 are joined by the tlat portion 19 and the upper arcuate portions of the ,f-s sides Tf? and ,t3 are joined by the arcuate connecting member The arcuate upper portion 29 of the casing 25 is provi' d with a spout 32 at the front end thereof which communicates with the interior of the casing The spout 32 is positioned immediately below the cooperating contacts ifi-i3d when the bridge 14 is in the closed position of Figure l.

The casing 2S comprised of the parallel V-shaped sides 7' and l?. and the top and end portions 19 and 2G is a relatively simple construction which may be a molding or any desirable construction. lt will be noted that the right hand end 2'7 of the casing 25 may be opened as the vane 2G, hereinafter more fully described, will serve as the end wall. The above described casing 25 forms the rst major part of my novel air puller. The casing 25 is provided with an extension 2 which is pivotally connected to the bridge 12 by the pin 26.

The second major part of my invention of a novel air puiler is the vane 23 which is pivotally mounted at one end by the pin 29 on the lower terminal 12. The vane is also pivotally mounted at a point intermediate its extreme ends by means of the pin 30 to the lower portion of the easing 25. The vane 28 is provided with a cut out portion to receive the gasket 31 which properly seals the vane with respect to the casing 25 so that there will be no air flow to the left during the opening motion of the circuit breaker 10.

Since the end cross-sectional view of the casing 25 is U-shaped, the circular gasket 3l will also be U-shaped.

The operation of the air puller is as follows: On the occurrence of a fault or short circuit on the line, the bridge 14 will be moved in a counterclockwise direction around its pivot point 15 in a manner well known in the art. Since the casing 25 is pivotally secured thereto at the pivot point 26, the casing will also be rocked to the left. Due to the pivotal connection 30 between the casing 25 and the vane 28, the vane will also be pulled toward the left. However, since the vane 28 has a stationary pivot 29, it will have an arcuate movement about its fixed center whereas the movement of the casing 2S will be limited due to its pivot points 26 and 30. Hence, even through the vane 28 and casing 25 are both moved to the left, the vane 28 will have relative movement with respect to the casing 25 and hence, will be moved from the right hand portion thereof toward the left hand portion thereof. rl`he boundaries of the casing will be contiguous to the vane at each angular position as it moves counterclockwise from the right side of the casing 25 to the left side thereof.

This sweeping movement of the vane 23 will urge the air housed within the casing 25 to ilow out of the spout 32 toward the cooperating contacts 13-13a- Thus, an air stream will be directly exerted on the arc which emanates from the cooperating contact thereby causing it to lift ott the Contact and be transferred to the are horn and into the arc chute not shown).

The final position of the air putter 1.6, when the circuit breaker is in the open position is illustrated in Figure 2. It will be noted by comparison of Figures l andl 2 that the spout 32, although initially positioned under the upper line terminal 11, moves out from under this unit so that the air is not trapped thereunder where it would ordinarily be inetective, but instead will follow the arc aS it is elongated during the opening movement of the bridge 14.

It will be noted that the pantograph arrangement of the air puer 16 created by the stationary pivot 16 and the movable pivots 26, 30 provides a multiplied motion tor the vane 28 with respect to the bridge 14.

In the particular arrangement shown in Figures l and 2, thc magnitude of the angular Velocity of the vane 28 is approximately 50 percent greater than the angular velocity of the bridge 14. Thus, this multiple action permits both a greater value of air to be forced on the arc and also provides for increasing the rate of air liow.

It will be noted that the air putter has its primary utility when the circuit breaker is required to interrupt a relatively small fault current. That is, if the circuit breaker ordinarily relies on a blow out coil to lift the arc for the cooperating contacts 13-13a, the ampere turns of thc blow out coil may not create a suihcient magnetic force to lift the arc. Thus, in order to insure that the arc will be lifted into the arc extinguishing means when the circuit breaker opens on a relatively small fault, the air putter 16 will provide a stream of air which will force the arc oft the cooperating contacts and into the arc chute. It is desirable that this happens during the initial part of the opening stroke so that the arc can be extinguished as soon as possible.

With my novel air putter, it is possible to control the rate of air flow within the point of the opening stroke so that a predetermined maximum rate of air How will occur at the initial part of the opening stroke.

The angle formed by the line adjoining the pivots 26-3t and the pivots 29-30 when the bridge 14 is in the closed position will govern the rate of the air flow at any point in the opening stroke. Thus, for example, by making this angle an acute angle, when the circuit breaker is in the closed position, the rate of air ow through the spout 32 of the pufrer 16 will be at a maximum at the start of the opening stroke thereby making the unit more eiicient, since the air is most eiectively used early in the stroke when the arc is initially created.'

Accordingly, I have provided a novel design for air puffers which requires only a vane and a casing whereby a large rate of air ow at the initial point of the opening stroke can be directly applied to the cooperating contacts.

In the foregoing, I have described my invention only in connection with preferred embodiments thereof. Many variations and modifications of the principles of my invention within the scope of the description herein are obvious. Accordingly, I prefer to be bound not by the specific disclosure herein but only by the appending claims.

I claim:

l. An air puifer for a circuit breaker comprising a casing and a vane; said casing pivotally mounted on a bridge of said circuit breaker; said vane pivotally mounted on one terminal of said circuit breaker; said vane also pivotally mounted on said casing; said vane and said casing both having angular movement during the opening movement of said bridge.

2. An air putter for a circuit breaker comprising a casing and a vane; said casing pivotally mounted on a bridge of said circuit breaker; said vane pivotally mounted on one terminal of said circuit breaker; said vane also pivotally mounted on said casing; said vane and said casing both having angular movement during the opening movement of said bridge; said vane having movement relative to said casing.

3. An air puffer for a circuit breaker comprising a casing and a vane; said casing pivotally mounted on a bridge of said circuit breaker; said vane pivotally mounted on one terminal of said circuit breaker; said vane also pivotally mounted on said casing; said vane and said casing both having angular movement during the opening movement of said bridge; said vane having movement relative to said casing; said vane having a magnitude of angular velocity greater than the angular Velocity of said bridge.

4. In a circuit breaker having an upper and lower terminal; a bridge and a pair of cooperating contacts mounted on said upper terminal; said bridge pivotally mounted on said lower terminal; the other of said cooperating contacts mounted on the free end of said bridge; an air putter comprising a casing and a vane; said casing pivotally mounted on said bridge; said vane pivotally mounted on said lower terminal; said vane pivotally mounted on said casing; :said casing having a spout positioned below said cooperating contacts when said cooperating contacts are engaged.

5. In a circuit breaker having an upper and lower terminal; a pair of cooperating contacts and a bridge;

one end of said bridge pivotally mounted on said lower terminal; one of said cooperating contacts mounted on the other end of said bridge; said other cooperating contact mounted on said upper terminal; an air putfer comprising a casing and a vane; a first pivot pivotally mounting said casing on said bridge; a second pivot pivotally mounting said vane on said lower terminal; a third pivot pivotally mounting said vane on said casing; said rst, second and third pivot points forming a pantograph for said air puter to provide relative motion of said vane with respect to said casing.

6. In a circuit breaker' having an upper and lower terminal; a pair of cooperating contacts `and a bridge; one end of said bridge pivotally mounted on said lower terminal; one of said cooperating contacts mounted on the other end of said bridge; said other cooperating contact mounted on said upper terminal; an `air puier comprising a casing and a vane; a first pivot pivotally mounting said casing on said bridge; a second pivot pivotally mounting said vane on said lower terminal; Va third pivot pivotally mounting said vane on said casing; said iirst, second and third pivot points forming a pantograph connection `for said air puffer whereby movement of said vane is multiplied with respect to said bridge.

7. In a circuit breaker having an upper and lower terminal; a pair of cooperating contacts and a bridge; one end of said bridge pivotally mounted on said lower terminal; one of said cooperating contacts mounted on the other end of said bridge; said other cooperating contact mounted on said upper terminal; an `air putter comprising a casing and a vane; a first pivot pivotally mounting said casing on said bridge; a second pivot pivotally mounting said vane on said lower terminal; a third pivot pivotally mounting said vane on said casing.

8. In an air putter comprising a casing and a Vane; said casing pivotally mounted on a movable arm of a circuit breaker; said vane pivotally mounted on a terminal of a circuit breaker; said vane pivotally mounted on said casing; said casing having two spaced parallel walls substantially V-shaped with an arcuate top; a connection between said arcuate top and one side of said spaced parallel walls; said vane extending between the other sides of said spaced parallel walls; a spout in said Varcuate connection; said vane moved from the open side of said casing during the opening movement of said circuit breaker to thereby force a stream of air through said spout on the cooperating contacts of said circuit breaker.

References Cited in the le of this patent UNITED STATES PATENTS 2,399,485 Harlow et al. Apr. 30, 1946 2,491,964 Frink Dec. 20, 1949 2,552,427 Heidmann May 8, 1951 2,706,758 Thibaudat Apr. 19, 1955 FOREIGN PATENTS 121,529 Australia June 3, 1946

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