US2551293A - Reclosing circuit breaker - Google Patents

Description

May 1 1951 B. c. ROGERS RECLOSING cmcun BREAKER INVENTOR. Ear/ram C fayerzs.

2 Sheets-Sheet 1 Filed Feb. 4, 1949 1951 B. 0. ROGERS 2,551,293

, RECLQSING CIRCUIT BREAKER Filed Feb. 4, 1949 2 Sheets-Sheet 2 lZO 1N VEN TOR. Jar/ram C Faye/'5.

ATTO/PA/EX Patented May 1, 1951 UNITED STATES PATENT OFFICE 2,551,293 RECLOSING CIRCUIT BREAKER Bertram 0. Rogers, Sharon, Pa.

4, 1949, Serial No. 74,531

Application February 3 Claims.

This invention relates to circuit breakers and more particularly to automatically reclosing circuit breakers.

The principal object of the invention is the provision of a reclosing circuit breaker which will operate to open and subsequently reclose a circuit line at such time as an excessive load current occurs thereon.

A further object of the invention is the provision of a reclosing circuit breaker which may be simply and economically constructed and which is particularly adapted for incorporation with transformers situated in remote locations such as in rural electric service lines and the like.

A still further object of the invention is the provision of a reclosing circuit breaker which is entirely automatic in operation and which will operate to continuously open and reclose an overloaded circuit until such time as the overload condition is eliminated and without damage to the circuit breaker itself or the transformers or other elements protected by its operation.

A still further object of the invention is the provision of a completely automatic, thermally controlled circuit breaker that will open and subsequently close an electric circuit, either A. C. or D. 0., upon an overload occurring therein.

A still further object of the invention is the provision of an automatic, thermally controlled circuit breaker that will open upon being overloaded and reclose upon completion of a predetermined timing cycle and repeat the opening and reclosing cycle as long as the overload condition exists.

A still further object of the invention is the provision of an automatic reclosing circuit breaker incorporating thermal responsive means as a prime mover for the operating mechanism thereof, impedance creating means in the circuits supervised and heat storing means for the thermal control of the mechanism.

A still further object of the invention is the provision of an automatic reclosing circuit breaker incorporating magnetically controlled breakers and thermally controlled breakers, and the thermally controlled breakers incorporating impedance elements for dampening arcing on the said thermall controlled breakers.

A still further object of the invention is the provision of a reclosing circuit breaker incorporating means responsive to an overload on the circuit for introducing impedance means in the said circuit and breakers for said circuit respon- Sive to thermal action of the said impedance b: means for breaking said circuit and subsequently reclosing the same.

lhe reclosing circuit breaker disclosed herein is particularly adapted for protective use in connection with transformers and other power line equipment subject to temporary overloads and particularly such circuits as are commonly found in rural electrification systems where transformers and other circuit completing device are located in areas remote from the service centers, generating plants and the like.

The reclosing circuit breaker disclosed herein is capable of operating automatically and indefinitely without manual attention or resetting and is so designed as to protect itself in operation as well as the associated equipment in the circuit supervised by the device.

With the foregoing and other objects in view which will appear as the description proceeds, the invention resides in the combination and arrangement of parts and in the details of construction hereinafter described and claimed, it being understood that changes in the precise embodiment of the invention herein disclosed can be made within the scope of what is claimed without departing from the spirit of the invention.

The invention is illustrated in the accompanying drawing, wherein:

Figure l is a side view of the reclosing circuit breaker.

Figure 2 is a front view of the reclosing circuit breaker.

Figure 3 is a top view of the reclosing circuit breaker.

Figure a is a symbolic view of the reclosing circuit breaker and electrical circuits in connection therewith.

By referring to the drawings and Figures 1, 2 and 3 in particular it will be seen that a reclosing circuit breaker has been illustrated which comprises a mechanism preferably enclosed in a housing Hi capable of retaining a cooling liquid such as oil so that the mechanism of the circuit breaker is immersed therein. The mechanism itself includes a metal frame 1! having a pair of spaced, upwardly extending arms H, the metal frame ll supporting an insulating body member l3 which in turn is provided near the top thereof with two pairs of relatively stationary contacts 14 and 15. The contacts M are located on depending arms it which in turn are secured to the insulating body member [3 and the contacts 15 are mounted on plungers l! for horizontal movement with respect to supporting frame members 18. Springs l9 normally bias the contact members l inwardly of the device or toward the left as seen in Figure 1 of the drawings. A pair of movable contact buttons and 2| are positioned in operative relationship with the relatively stationary contacts 14 and I5 heretofore referred to, the movable contact buttons 29 being located on the upper end of a pair of movably mounted, self-aligning arms 22-42 which are in turn carried on a body member 23. The body member 23 has a depending, cross sectionally V-shaped lower edge 24 which in turn is pivotally engaged over the leading edge of a transverse frame member 25.

The frame member 25 is secured to the insulating member 13 and also serves as a means of mounting an electro-magnetic coil 25 in operative relation to the body member 23 so that upon the coil 26 being energized, the body member 23 will be moved thereagainst to effectively separate the contact buttons 20 and the contacts I 4 heretofore referred to. The body member 23 is secured in operative pivotal relation to the electro magnetic coil 26 by a pair of oppositely disposed springs 21 and 28 which are in turn secured to the frame member 25 and to a secondary pivoted body member 29, the uppermost end of which carries the movable contact buttons 2l2|. The lowermost end of the secondary body member 25 is provided with a depending cross sectionally V-shaped lower edge 30 engaged upon the leading edge of a secondary frame member 3| so that it may pivot thereon.

The upper end of the arms I6 are provided with connections 32 and 33 while the lower end of the provided with a pair of connections 34 and 35. The frame members l3 are provided with a pair of secondary connections 35 and 37 while the'body member 29 is provided with a pair of secondary connections 38 and 39, respectively. The arms IE on the frame ll extend upwardly at the sides of the device, as best shown in Figures 2 and 3 of the drawings,.and have journals 40-25 formed on their uppermost ends in which shafts 4! H are movably secured, the outer ends of the shafts 4l4l carrying connecting members 22 and 43, respectively, and the innermost ends of the shafts 4l-4| carrying body members 44 and 45, respectively. Each of the body members 44 and 45 has a spiral bimetallic element incorporating a plurality of convolutions secured thereto. The spiral bimetallic element secured to the body member 44 is indicated by the numeral '46 and the spiral bimetallic element secured to the body member 45 is indicated by the numeral 41.

For the purpose of simplicity and clearness of illustration, the spiral bimetallic elements 46 and 41 have been illustrated with a relativey few convolutions, it being understood that a number of convolutions incorporated in each of the spiral bimetallic elements 46 and 4'! may obviously comprise a greater number than those illustrated.

The outermost ends of the spiral bimetallic elements 45 and 4'! are respectively secured to insulating body members 43 and 49 as by means of fasteners and 5!, the insulating body members G3 and '19 extending rearwardly with respect to the forwardly positioned ends of the bimetallic elements 46 and 4'! and provided-with pivots 52 and 53 adjacent their rearmost ends. The pivots 52 and 53 are secured in turn to the outer most ends of a cross arm 54 which is pivoted midway between its ends by a pivot 55 to a slide piece 56, of which is bifurcated and which bifurcated ends are secured to a transverse member 5'! as by means of fasteners 58. The transverse member 5! is provided with'an elongated slot 59 and a forward extension 68 which in turn is bifurcated at its foremost end and forms a pivot point with respect to a pivot member 6| positioned transversely therethrough for one member of a toggle assembly, generally indicated at 62, and operative by forward and backward movement of the transverse member 57.

The toggle member 52 includes a spring 63 and a toggle piece 6 the lowermost end of which engages a cross piece65 on the upper end of the secondary body member 29 heretofore referred to. The toggle piece 64 is pivoted on a transverse pivot 55 between a pair of extensions 61 formed on the insulating body member 53, heretofore described.

By referring to Figure 3 of the drawings it will be seen that the slide piece 56 is carried on the upper surface of the insulating body l3 and is obviously positioned thereon so that it is capable of relatively free forward and backward movement with respect thereto as occasioned by the spiral bimetallic elements 46 and/or 41 which are connected with wardly and backwardly (from left to right as seen in Figure 1 of the'drawings, or from top to bottom as seen in Figure 3 of the drawings), its action will move the toggle member 62 so that it pivots on a rod 68 and compresses the coil spring 63 and changes its angle of thrust with respect to the toggle piece 54 so as to cause the same to pivot on the transverse pivot 66 and apply motion to the secondary body member 29 so as to move the contact buttons 2! inwardly and away from their normal engagement with the contacts 15.

It will also be seen that at such time as the electro-magnetic coil 26 is energized as from an overload the body member 23 will move the arms 22 thereon and thereby separate the'contacts 25 with respect to the contacts M. The foregoing relates to 'the mechanical construction and operation of the circuit breaker and re'closer and the following comprises a description of the operation of the device as may be best understood by referring to Figure 4 of the drawings.

By referring to Figure 4 of the drawings a symbolic wiring diagram is illustrated in connection with representations of certain of the mechanical portions of the device. It will be seen that conductors 1B and TI comprise a power source carrying, for example, 120 volts each while 'an directly with the secondary of the protected transformer (not shown) and they will be seen to connect with separate windings 13 and 74 forming together the electro-magnetic coil .26 heretofore referred'to. The coil l3 connects with a conductor 75 which is connected with the connector d3 on the shaft ll and establishes electrical connection with one end of the bimetallic element 4'! by way of the body member 45. A branch of the conductor 75 also connects with one of the pair of contact buttons 23 which are movably mounted by the arms 22 on the body member 23. A conductor 76 connects one'o'f the fixed contacts I 4 with a load line 17 and also with one of the'contacts 15 as heretofore'describe'd. The other coil '14 which is connected with'the supply line H is connected by way of a conductor the slide piece 56 with to the contacts l4-l4.

18 with the connector 42 and one end of the bimetallic element 46. A branch of the conductor 18 also connects with the other one of the contacts 20 on the other one of the pair of movable arms 22 on the body member 23. A conductor 19 connects the other one of the contacts I4 with a load line 80 and with the other one of the contacts l5.

It will thus be seen that normal flow of current through the device is through the coils 13 and 14 which together comprise the electromagnetic coil 26 heretofore referred to and that the said coil 26 thereby rides the line and normally does not sufiiciently attract the body member 23 to open the contacts 20-20 with respect However, in the event of an overload on either of the lines 11 or 60, the increased flow of current through the component coils 13 and 14 of the electro-magnetic coil 26 will sufficiently attract the body member 23 to cause it to move the arms 22 and move the contacts 20-20 away from the contacts l4-l4 and thus interrupt the normal current path through the circuit breaker. Still referring to Figure 4 of the drawings it will be seen that the bimetallic element 41 has the outermost free end thereof secured to a connector 0| on the innermost end of the body member 49 and a conductor 62 is also connected therewith and to one of the contacts 2| heretofore referred to and carried on the secondary body member 29 and normally engaged with one of the contacts which is in direct connection with the load line 11. The other one of the bimetallic elements end connected with a connector 03 which in turn is connected by a conductor 04 with the other one of the contacts 2| on the body member 29 and which is normally in engagement with the contact 15 connecting with the load line 60. It will thus be seen that in the event of an overload as heretofore described and the operation of the electro-magnetic coil 26 to open the contacts -20 with respect to the contacts l4-l4, the current flowing through the device is shunted through the bimetallic elements 46 and 41 where it continues to flow under relatively great impedance until such time as it heats up the bimetallic elements 46 suificiently to cause them to move one or both of the body members 48 and 49 which will impart motion to the cross piece 54 and the slide piece 56 and hence to the toggle mechanism 6|, 62, 63 and 64 and thereby cause the lower end of the toggle piece 64 to engage the secondary body member 29 and move it inwardly thereby breaking the circuit between the contacts 2l-2l and the contacts 15-15.

It will be apparent to those skilled in the art that there will be little or no arcing between the contacts 2l-2l and l5-l5 as the insertion, in effect, of the high impedance in the circuit resulting from the connections through the spiral bimetallic elements 46 and 41 will dampen out the normal arcing tendencies completely or nearly so. In addition to the dampening tendencies with respect to arcing accomplished by shunting the current through the spiral bimetallic elements 46 and 41, the resistance offered by these elements will result in heat storage thereby which becomes a prime mover with respect to the body members and 49 operating the cross piece 54 and the toggle mechanism.

It will also occur to those skilled in the art that the normal cooling of the bimetallic elements 46 and 41 will be at a predetermined rate 46 has its outermost or free and that as they cool they will reassume their normal positions at which time they will actuate the toggle mechanism to permit the circuit to be re-established. In the event the cause of the overload has been removed from the line, the service will remain uninterrupted. If, however, the overload conditions still exist, the device operates again and again on the same cycle until such time as the overload condition is removed.

It will be seen that the contacts 20-20 on the body member 23 are opened responsive to increased current flow through the electro-magnetic coil 26 and that they are maintained in opened position at such time as the body member 29 is moved by the toggle piece 64 by reason of an arm formed on the body 29 and extending inwardly and adjacent to the front side of the body member 23. Thus, the action of the toggle mechanism and particularly the movement of the toggle piece 64 against the secondary body member 29, responsive to the operation of one or both of the spiral bimetallic elements 46 and 41 serves to move the contacts 2l-2l away from the contacts I4-l4 and at the same time hold the body member 23 against the electromagnetic coil 26 and thus maintain both pairs of circuit controlling contacts 20-20 and 2l-2l open until such time as the bimetallic elements 46 and .41 reassume their normal position and actuate the toggle piece 64 to release the secondary body member 29. Both the secondary body member 29 and the body member 23 are returned to normal position to close the contacts 20-20 and l4-l4 and 2l-2l and l5-l5 by the springs 21 and 28 heretofore referred to.

It will thus be seen that a simple and efficient automatically reclosing circuit breaker has been disclosed which incorporates certain new and nove1 constructions and principles in the art primarily in that the device combines the electro-magnetic principle of circuit breaker operation with the mechanical motion originating in the spiral bimetallic elements when heated. The operation of the bimetallic elements and the mechanical breaker action is dependent on the initial operation of the electro-magnetic circuit breaker operation as the circuit normally flows through the contacts 20-20 and l4-l4 following the path of least resistance in the device and does not flow through the bimetallic elements 46 and 41 until the contacts 20-20 are separated with respect to the contacts l4-l4. This action results in directing all of the current through the bimetallic elements 46 and 41 and stores the heat necessary to actuate the toggle piece and break and eventually reclose the circuit through the contacts 2 l-2l and [5-H at the same time providing desirable impedance in the line to eliminate arcing on these contacts when they are separated.

It will be obvious to those skilled in the art that the circuit breaker disclosed herein is also responsive in operation to the temperature of the oil pool in which the same is normally located. For example, when used in connection with a transformer or similar object in the presence of a high steady state load, the temperature of the oil will increase to a point where it will cause the operation of the device by reason of its action on the spiral bimetallic elements hereinbefore described.

It will thus be seen that the several objects of the invention have been met by the circuit breaker and recloser disclosed herein.

1 Having "thus described claim is:

1. An automatically reclosing circuit breaker having two pairs of separable contacts normally biased to closed position, electromagnetic means to open a first pairof said separable contacts in response to overload current through said separable'contacts, thermally responsive elements connected in shuntcircuits around the first pair of separable contacts sive to motion generated by said thermally responsive elements when heated engaging and opening the second pair of separable-contacts and means movable by said structural means maintainingthe first pair of contacts open, whereby a circuit through the circuit breaker contacts is opened, said thermally-responsive elements when cooled permitting reclosure of both pairs of contacts' 2. Anautomatically reclosing circuit breaker having two pairs of separable contacts normally biased to closed position, a magnetic armature arranged when moved to" open a first pair of said separable contacts, electromagnetic coils posimy invention, what I a circuit through'the circuit breaker contacts is 1% opened, said thermally responsive elements when and structural means respon- Lil cooled permitting reclosure of both pairs of contacts.

'3. An automatically reclosing circuit breaker having two pairs of separable contacts normally biased to closed position, electromagnetic means to open a firstpair of said separable contacts in response tocverload'current through said separable contacts, spirally wound bimetallic elements connected inshunt circuits around the first pair of separable contacts and structuralmeans responsive'to motion generated by said spirally wound bimetallic'elements when heated for engaging and opening the second pair'of separable contacts and'means movable by said structural maintaining the first pair of contacts open, whereby -a circuit through the circuit breaker contacts is opened, said bimetallic elements when cooled permitting reclosure'of both pairs of contacts by energy generatedand stored'in the said spirally wound bimetallic elements by the opening operation.

BERTRAM C. ROGERS.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS

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