US2049328A - Electric circuit interrupter - Google Patents

Description

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ELECTRIC CIRCUIT INTERRUPTER Filed June 21, 1934 `Fipa- Inventor'. Wilfv'ed F 5k g kfw/@thorn dit Patented .luly 2d, i936 unnornrc omom'r m'rnnnt i Wilfred F. Slkcats, Scotia, N. Y., assigner to General Electric Company, a corporation ot New York Application .lune 2l, 1934, Serial No. 731,655

lll Claims.

My invention' relates to electric circuit interrupters. more particularly to those of the iluidblast type wherein a source of pressure is utilized to effect a blast of arc-extinguishing liquid through a break. in the circuit to be interrupted, and has for its principal object the provision of an improved circuit interrupter of the aforesaid type which shall have high interrupting capacity and be efcient and positive in operation, and simple and compact in structure.

In accordance with my invention, an explosive charge arranged to be ignited in response to a predetermined circuit condition comprises a source of pressure for separating the circuit controlling contacts and for driving a jet of insulating or arc-extinguishing liquid through the arc formed at said contacts.

My invention will be more fully set forth in the following description referring to the accompanying drawing, and the features of novelty which characterize my invention will be pointed out with partlcularity in the claims annexed to and forming a part oi this speciiication.

Referring to the drawing, Fig. l is an elevational view, partly in section, of a circuit interrupte'r embodying my invention; Fig. 2 is a similar view showing at an angle of 90 a portion of the device shown by Fig. l; Fig. 3 is an elevational view, partly in section, of another form of duid-blast circuit lnterrupter embodying my invention; and lii-g. t is an elevational and exterior side view, partly in section, of the device shown by Fig. 3.

The circuit interrupter illustrated by Fig. l comprises a cylindrical casing i of suitable insulating material closed at its opposite ends, as

' by caps 2 and il, and containing an arc-extinguishing liquid t, as insulating oil for example. immersed in the insulating liquid are circuit controlling means adapted to form a break in the circuit to be controlled, as a stationary contact t and a movable contact t. An insulating baiiie i, likewise immersed in the liquid t, has formed therein a passage t extending transversely of the break at the contacts t and t and communieating with opposite sides of the baille. As illustrated, the separation of the contacts t and ti takes place within the passage t so that pressure within 'the liquid t beneath the baie is efiective to cause an arc-extinguishing blast of liquid transversely through the arc and into the exhaust region above the baille.

For the purpose of effecting separation of said contacts coincident with said liquid blast, an explosive charge t, which may comprise a suit- (Cl. 20G- 1593) able slow burning powder, is arranged to transmit pressure to the liquid t in response to a predetermined circuit condition. To this end a removable cartridge l is connected, as at Il, to the end cap 3 so as to be immersed in the insulating liquid and to make butt contact at l2 with the lower end of the conductor stud i3 connected to the contact 5. The opposite ends of the cartridge IU are electrically interconnected by a fus1b1e element or link it which is illustrated as 10 being in seriesv with the contacts 5 and B and surrounded by the explosive charge 9.

The movable contact t is normally biased as by a spring it into engagement with the Contact t and is operatively connected to a pair of pistons it (Fig. 2) extending through the baffle 'l at opposite sides of the contacts into the pressure chamber beneath the bae. The casing l is pro vided with a protective insulating lining il and a depending baille it serving both to mount the 2o conductor stud i3 and to form a gas pocket at i9 beneath the baiiie 'i'. In the operation of the device melting or heating of the fusible element it in response to excess current causes instantaneous ignition of the explosive charge 9 and a consequent rapid rise in iiuid pressure beneath the baiiie l. Asa result, the pressure acting on the pistons it causes immediate separation of contacts 5 and 6 coincident with a blast of the insulating liquid through the 3o passage t and across the arc therein. The gas cushion within the pocket i@ serves to prevent excessive bursting pressures within the casing.

It will be apparent that the contact t may be held open by a simple manually or electrically controlled latch if desired, although this is not necessary in view of the fact that a break in the circuit is formed by the explosion vof cartridge i t. The insulating liquid t serves to prevent reignition of arcing at this break, thereby maintaining the circuit open. y

The explosive charge t may obviously be ignited in response to any predetermined circuit condition as, for example, by current in the usual current transformer or by a conventional relay. The pressure generated by the explosive charge is independent of the current to be interrupted and may be so proportioned that the most effective liquid blast is obtained for a given rating of circuit interrupter.

Fig. 3 illustrates a form of circuit interruptor embodying my invention wherein separation of the contacts and the oil blast are effected by an explosive charge arranged so that the products 0i Qombustion do not mingle with the oil or insulating liquid. With this arrangement an insulating casing is partly filled with oil, as indicated, and comprises a lateral extension 2| forming a cylinder` within which a piston 22 is mounted for reciprocal movement. As illustrated, the piston 22 is resiliently biased as by a spring 23 bearing on a stud 24 upwardly and in opposition to the force for creating pressure in the oil body the level of which is indicated at 25.

The contact structure is immersed in the oil body and comprises a stationary contact 26, a relatively movable contact 21 resiliently biased as by spring 28 towards closed circuit position. The contact 21 is maintained in open circuit position as by a spring biased latch 29 pivoted, as at 30, with respect to the casing 20. The contacts are suitably mounted within insulating baille structure 3| which provides a guide at 32 for the movable contact and is provided with an aperture at 33 forming an exhaust passage into the upper low pressure space 34 of the casing. An arc-splitting baille 35 of suitable insulating material is mounted within the casing so that exhaust of oil from the lower part of the casing blows the arc between the contacts 26 and 21 transversely thereof.

The contacts 26 and 21 are arranged so that When in the closed circuit position they substantially close the exhaust passage 33. Since the baille structure 3| otherwise substantially closes off the lower part of the casing, it will be apparent that the sudden pressure created within the oil body beneath the baille is eilective to move the piston-like contact 21 quickly to the latched open circuit position illustrated and to force a free blast of oil upwardly through the passage 33 and transversely of the arc formed between the s-eparating contacts. As used herein the term free blast means an unobstructed arc-extinguishing liquid blast subject to inappreciable back pressure in the pressure relief or low pressure chamber.

The circuit controlled by the contacts 26 and 21 includes the conducting end caps 36 and 31 forming the circuit interrupter terminals, the terminal 36 being connected to the movable contact as by rigid and flexible conductors 38 and 39, respectively, and the terminal 31 to the stationary contactv 26 as by the rigid conductor 40.

For the purpose of driving the piston 22 into the oil body for creating the aforesaid pressure in response to a predetermined circuit condition there is provided an explosive charge 4| which surrounds a fusible element or the like 42. The element 42 need not necessarily be fusible. A light wire of high melting point metal might be in some cases preferable. It shall therefore be understood that the term fusible as hereinafter used is intended to comprehend means as above described. 'Ihe explosive charge is in the present instance disposed within expansible enclosing means as telescopic structure including relatively movable telescopic members 43 and 44, each closing one end of the other as illustrated. The aforesaid telescopic structure is mounted within a suitable revolver 45 adapted to surround the casing 20, as illustrated, for supplying a plurality of charges to the piston 22.

The revolver per se forms no part of the present invention and any suitable arrangement, such as that shown for example by Read U. S. Patent 123,183 of March 11, 1903, may be provided for bringing into position above the piston 22 a new charge in response to a circuit opening operation.

Mounted directly above the explosive charge is a stationary breach block 4B adapted to engage and electrically contact with the 'closed end of the telescopic member 43.

The electric circuit including the fusible or heating element 42 for firing the explosive charge 5 4| includes a terminal member 41, breech block 46, telescopic members 43 and 44, piston 22, Wiping contact 48, conductor 49 and terminal structure 50. The terminal structure 50 is suitably insulated as at 5| with respect to the breech block 46 so that in the position illustrated a complete circuit, including the fusible element 42, exists between the terminals 41 and 5D.

The element 42 may be blown or heated in respense to a predetermined circuit condition as, for example, by connecting terminals 41 and 50 to a current transformer or to a relay circuit which is in turn responsive to a predetermined circuit c'ondition.

With the contacts 26 and 21 in the closed circuit position blowing of the fusible element 42 and ignition of the explosive charge 4|, which preferably comprises a slow burning powder, results in downward movement of the telescopic member 44 since the member 43 is maintained 25 stationary by the breech block 46. 'I'he piston 22 is accordingly driven into the oil body eiecting the above-described contact separation and oil blast until the telescopic member 43 clears the exhaust port 52 of the member 44 permitting 30 the products of combustion to exhaust through passage 52 into atmosphere. There is, therefore, no opportunity for the explosive charge to mingle with the oil or insulating liquid and affect the insulating characteristics of the same.

After the circuit opening operation, the spring 23 returns the piston 22 to the initial position illustrated and another explosive charge is rotated by the revolver into position. 'I'he latch 29 which holds the contact 21 in open circuit position may be suitably released as by a plunger 55 extending within the casing, as illustrated in Figs. 3 and 4.

The latch releasing mechanism for closing the circuit interrupter may be controlled in any suitable manner as by a remotely controlledxsolenoid 56 coacting with a bellcrank 51 through attached link 58. Upon energization of the solenoid 56 the plunger thereof engages the link 58 causing counter-clockwise rotation of the bellcrank 51 and depression of the plunger 55 to release the latch 29.

Additional controlling and indicating means may comprise a plvoted member 59 having one arm 60 in the path of the bellcrank 51 and another arm 6| in the path of a plunger 62 extending through the casing I into the oil body 25. The plunger 62 is provided with a slot 62 through which the link 58 is loosely guided for a purpose hereinafter described.

During the circuit closing operation initiated by energization of solenoid 56, the bellcrank 51 engages the arm 60 to cause clockwise rotation thereof to the position illustratedso that the arm 6| is practically in engagement with the plunger 65 62. Return of the bellcrank 51, as under the iniluence of the latch spring, to its initial position therefore need not affect the position of the member 59. When, however, the circuit is opened the fluid pressure created within the casing pro- 70 jects the plunger 62 upwardly to engage the arm 6| and cause counter-clockwise rotation to the Aopposite position. The link 58 is likewise lifted by the plunger 62 so as to be out of the path of the closing solenoid plunger, thereby permitting 7G.

aoaasss latching of the movable contact in closed circuit position. In order to eiect another reclosing operation, deenergization and subsequent energization of the solenoid 56 are necessary. This will be apparent since the plunger 62 drops back to its initial position after decrease of pressure within the casing, thereby permitting the link E8 to drop into position in alinement with the solenoid plunger.

It will be apparent that the member 59 may yactuate suitable indicators as illustrated or signal controlling contacts' in a well known manner, the latter apparatus being omitted from the drawing in the interest of simplicity and clearness.

It should be understood that my invention is not limited to specic details of construction and arrangement thereof herein illustrated, and that changes and modifications may occur to one 'skilled in the art Without departing from the spirit of my invention.

What I claim as Anew and desire to secure by Letters Patent of the United States is:

l. A circuit interrupter of the :duid-blast type comprising a casing containing an arc-extinguishing liquid, an explosive chargefor transmitting pressure to said liquid, circuit controlling means immersed in said liquid adapted to form a break in the circuit to be interrupted, and means for igniting said charge and for forming said break l in response to a predetermined circuit condition, the pressure generated by said explosive charge directing a freeblast of said liquid through said break and beyond the same.

2. A circuit interrupter of the fluid-blast type comprising a casing containing an arc-extinguishing liquid, an explosive charge for transmitting pressure to said liquid, circuit controlling contacts immersed in said liquid, and means for ig- 'uiting 'said charge and for separating said contacts in response to a predetermined circuit condition, the pressure generated by said charge likewise directing a freeblast of said liquid between and beyond said contacts.

. 3. A circuit interrupter ol' the duid-blast type comprising a casing containing an arc-extinguishing liquid, an explosive charge and circuit controlling contacts immersed in said liquid, a fusible element for igniting said charge in response to a predetermined' circuit condition, land pressure-actuated means operatively connected to said contacts, igniting of said explosive charge A i causing separation oi said contacts and a free i blast of said liquid between and beyond the same.

4. A circuit interrupted of the fluid-blast type comprising a casing containing an insulating liquid, a fusible element surrounded by an ex- 1- plosive charge immersed in said liquid, lcircuit 1 controlling means adapted to form a break in the circuit to be interrupted in series with said fusible g element, and means for directingpressure generated `in said liquid by blowing of said fusible element and igniting of said explosive charge for creating the aforesaid break and for directing a free blast of said liquid throughthe same.

5. A circuit interrupted of the duid-blast type i comprising a casing containing an insulating liquid, an explosive charge for transmitting pressure to said liquid, circuit controlling contacts immersed in said liquid insulating bame structure forming a passage disposed transversely o! said contacts and piston structure associated with said contacts, pressm'e generated by said explosive charge actuating said piston structure to separate said contacts and eiiect a iree blast of insulating liquid through said passage' transversely of the arc between said contacts..

6. A circuit interrupter of the fluid-blast ty comprising a casing containing an arc-extinguishing liquid, and means for transmitting 'pressure 5 to said liquid for eilecting a circuit interrupting operation including expansible enclosing l'means containing an explosive charge, means ior igniting said charge in response to a predetermined circuit condition, ignition of said charge eilecting expansion of said enclosing means for transmitting pressure to said liquid while maintaining the products o! combustion out of contact with said liquid.

7. A circuit interrupter of the fluid-blast type comprising a casing containing an insulating liquid, circuit controlling contactsimmersed in said liquid, pressure generating means for transmitting pressure to said liquid for separating said contacts and effecting a blast of said liquid 20 between the same for extinguishing arcing including a pair of relatively movable enclosing members and an explosive charge within one of tiiem.

8. A circuit interrupter of the uid-blasttype comprising a casing containing an arc-extinguishing liq'uid, means for transmitting pressure to said liquid for effecting a circuit -interrupting operation including a pair of relatively movable telescopic members containing -313 an explosive charge, a piston communicating with said liquid connected to one of said members, and means for igniting said explosive charge in response to a predetermined condi.- tion so that relative movement of said telescopic members causes said piston to create a circuit interrupting blast of said liquid.

9. A circuit interrupter of the fluid-blast type comprising a casing containing an arcextin= guishlng liquid, circuit controlling contacts immersed in said liquid, insulating 'baile Structure associated with said contacts arranged so that pressure created within said liquid causes separation of said contacts and a blast of said liquid transversely of the gap between the same, means for creating pressure insaid liquid including a pair of relatively movable telescopic members containing an explosive ch, a piston immersed in said liquid connected to one of said members, means for igniting said explosive charge in response to a predetermined circuit condition, whereby relative movement o! said telescopic members is eiected together with a circuit interrupting stroke of said piston, latching means for maintaining said contacts in open circuit position, means causing closing of said contacts in response to release of said latching means, and means returning said piston to its initialposition.

10. In a circuit interrupter of the nubi-blast @o type comprising a casing containing an arc-extinguishing liquid, circuit controlling contacts sep- -arable in response to pressure created in said cuit position. 75

11. A circuit interrupter of the Huid-blast type comprising a casing, circuit controlling contacts in said casing, a latch for maintaining said contacts in open circuit position, means for releasing 5 said latch thereby causing closing of said contacts, means actuated' by fluid-blast pressure during a `circuit opening operation, and a movable member arranged operatively toy `con'nectfs d: latch and said -releasing means, said.pre'ssur actuated means arranged to movesadmembe into inoperative position with respect atol s leasing means. i

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