US1805497A - Electric switch - Google Patents

Description

W., E. PAUL ELECTRIC SWITCH May 19, 1931.

Filed Dec. 24. 192B 2' Sheets-Sheet 1 Inventor 0 m J pwm E r m d w A U s Iv .lu H H May 19, 1931. w, 5, U 1,805,497

ELECTRIC swmzm Filed Dec. 24. 1928 2 Sheets-Sheet 2 Inventor WLLLLam E.Po.uL, b5 HLs Attorneyv additional matter. 25

- an improved switch of this character which Patented May 19, 1931 UNITED: STATES PATENT OFFICE WILL AM E. VPAUL, or scrimr'ne'mmr, NEW Yonx, ASSIGNOR "rfo emvmur. mare COMPANY, A conrona'rron or mewxonx ELECYBRIC swircn Application filed December 24, 1928. Serial-No. 328,161.

My invention relates to electric switches and particularly to switches for interrupting modern alternating current .commercial power circuit. Switches commonly used for controlling such-circuits have their contacts power that may be interrupted by such a' switch is dependent to a large extent upon the amount of gas that-is formed by the are drawn between the contacts before it is finally extinguished. Any means therefore that will lfireduce, the amount of gas formeddn the switch or prevent it entirely is an important factor in effecting the interruption of the circuit. v

This application is a continuation in part of my application Serial Number 281,480,

filed May 29, 1928, for electric switches, the disclosures ofsaid prior application. being embodied in this application together with Oneobject of my invention is to provide shall cause the contacts at the final break to separate only at or near thezero value ofthe current wave. 3

Another object of my invention is to provide improved means for causing any are that maybe drawn between the contacts of the final break-to be transferred quickly from the contacts and the contacts to become insulated from each otherby a layer of the insulating liquid. Another object of my invention is the provisionof a liquid break switch having main and arcing contacts and improved means for expelling laterally from the main contacts and the switch operating means any are and gas formed at the arcing contacts.

A; further object of my invention is the provision of a liquid break switch. whereni the circuit is broken simultaneously ata plurality of points in series, the arcs at. the several points being expelled laterally and the cooperating contacts immediately insulated from each other by insulatingliquid.

My invent'on will be better understood from the following description taken in connection with the accompan ing drawings, and'its scope will be pointe out inthe appended claims.

Referring to thedrawings, Fig. 1 is 'a view partly in section and partly in elevation of a switch embodying my invention the parts being shown in close circuit position; Fig. 2

is a sectional View f a portion of the same taken 011 theline 2-2; F i". 3 is similar to Fig. 1 except that it shows the switch in open circuit'p'osition; Fig. 4 is across sectional view'of Fig. 3 showingthemovable arcing contacts; Fig. 5 is a circuit diagram; and- Fig. 6 illustrates a modification. 7 Through the top of the enclosing vessel 1 containing insulating liquid extend the 1nsulatingbushings 2 connected by braces 3 and surrounding-the studs 4: in accordance with well known oil switch construction. At-

tached to he lower .end of each bushing 2 is number of chambers, in the present case three,

by the insulating partitions 8. .The number of chambers provided depends upon the number of series breaks in the circuit .which the switch is desired to make and obviously the number may be varied to suit particular conditions. In the several chambers are similar blow-out. coils, each comprising the coil 10 formed of several turnsof fiat conductor around the core 11 and secured to the ends of each core are the plates 12 forming pole pieces, the sh ape of the plates being indicated by dotted lines in Fig. 1. One end. of each coil connects with one of the fixed arcing contacts 13 arranged between the pole pieces 12.

The opposite end. of one of the coils isconnected directly by conductor 14 with the adjacent stud 4 whlle theopposite-ends of the other-two coils are connected together as shown in Fig 2 and in the circuit diagram.

The direction of current in the coils 10 is' such that the magnetic flux between the pole pieces reacts with the arcs drawn from the contacts .31 to push them outwardly through the open side of the housing. Thus the arcs in the two housings are expelled in opposite directions toward the adjacent tank walls and away from the main contacts and operating rod to be described later. Each chamber of the housings has the curved wall and is shaped v to form an arc chute, the coil being protected by the wall from the arc. On the outer face of this wall is the conducting arc runner 16 whichconnects at its lower end with the fixed contact 13. That part of the housing forming the lower wall of the are chute has an opening to receive the movable arcing contact 17 and is provided withthe barrier 18 below which isthe conductin member 19. This .member-is slidably. secure to the housin' by the bolt 20 and is pressed against the si e of the movable contact 17 by the spring 21. At

. the side of the'fixed contact opposite the bar rier 18 the housing is formed with the cavity 22, .the purpose of which will be explained later. c v

. The operating rod 25, the-lower portion at least of which is of insulating material, has I secured to it the main current ca'rryin bridge 26 and the arcing contact bridge 2 The -former.bridge when the switch-is closed con:

tacts with the main fixed contacts 28 which are mounted on adjacent faces of the housings 5 and which by the conductors 29 connect with the studs 4. Bridge 27 comprises two transverse metal plates 30 fixed to the oper ating rod and having lateral projections bolted to the three pairs of insulating plates .31. At each end of each pairof plates there is secured the sleeve 32in which slides, the

I movable arcing contact 17. lvlg'yement of contact 17 in its sleeve is limited the pin 33 fixed in the sleeve engaging the ends of the slot 34 in the-contact. Coil spring 36 mount- .ed within the contact between the upper end thereof and the pin holds the cooperating arcing cont acts together during the initial opening movement of the switch. To bracket 37 secured tothe bridge 31 is pivoted the arm 38 at the opposite end of which is the pawl 39 and on the side facingthe pawl the contact 17 has a series of teeth or notches 40 forming a ratchet adapted to be engaged by the pawl. At its pivot endthe arm is connected to the contact 17 by the flexible conductor 41 and at its opposite end it is connected by flexible conductor 42 to member 43 of the bridge. The

two outer members-42 at each end of the,

bridge are electrically connected together by the strap 44 and the-corresponding middle members 43 of the bridge are connected. to-

loop. In accordance with'well known laws current traversin the switch produces in each loop a. magnetic ux which tends to cause the loop to enlarge. The arm 38 forming as it does a corresponding side of both loops it tends to rotate in a direction to withdraw the pawl from the contact 17. This movement is opposedby' the spring. 47'whose tension is" such, that the pawl is caused to engage the ratchet on contact 17 when the instantaneous value of-the alternatin current is zero or. 15

.close to zero. A suita le stop 48 limits the movement of the arm 38 to a point at which the pawl just clears the ratchet teeth. Accordingl it will be noted that the pawl and ratchet orm a disengageable' clutch connection between the bridging member 27 and contact 17 When the switch is inclosed cir- I cuit position illustrated by Fig. 1 the spring 36 is compressed thus holding contact 1 againstcont'act 13. As the switch moves to 'open circuit position, main bridging member 26 separates from contact 28 transferring the load to contacts, 13 and 17 which are held together by'the force of spring 36. So long as the instantaneous value of the current wave is other than zero or nearzero, arm 38 with pawl 39 will be held against stop 48 but as soon as the value of the current wave falls to zero or near'zero the electroma netic force on the arm 38is overcome by the orceof spring the pawl enga es the ratchet. The ridging 47 and member 27 an associated parts have by this time gained greater speed. and by the engagement of the pawl andratchet quickly separate the arcing- contacts 13 and 17 If this separation occurs exactly at the zero value of the current, no arc 1s drawn between these con- 7tacts. If however it does not occur exactly 1 at zero but close'to it, a small arc is drawn whichis immediately expelled into, thearc chute 11 by the blowout coil as indicated bythe dot and dash linesin Fig. 3, the ends of the are being transferred from the contacts 13 and '17rrespectively'to the runner 16-and the contact 19. This blowout action is .very

rapid so that the arc is b roken while the instantaneous value of the current isstill small. 1

The are in being transf-erredfrom contact 17 to contact 19 jumps the-barrier '18 whence the are current passes to or from contact 17' through the sllding connection between --itand contact 19. The arc and are gases having been expelled into the chute, cool insulating liquid from cavity 22 fiowsdown over the end of cont-act 17 as soon as it passes below barrier 18. To facilitate this flow of liquid, openenclosingthe cavity. This covering of thecontact 18 by insulating liquid prevents a reestablishment of the arc when the voltage is again restored? By the continued open circuiting movement of the switch the'main and arcing contacts are carried to a full open posi tion such as shown for example by Fig. 3.

'ings, not showin, are left in the housing 5 'Upon reclosing the switch the arcing contacts first connect with each other, the pawl 39 slid ng over the ratchet 40 while the spring 35 is compressed. Finally when the parts reach the fully closed position shown'in Fig.

1, both'arcing and main contacts are in engagement.

In addition to its effect in expelling the arcs into the chutes, the blow-out coils also a zero value.

assist in the operation of the arms 38. The

flux from each coil being in such a direction as to drlve the arc outwardly'exerts a" thrust inwardly on the arm augmenting the electromagnetic eflect of the loop of which the arm forms a part. r I

'In the modified form of my invention shown in Fig. 6, the movable contact is held in engagement with the. fixed contact by the electromagnetic force of the current travel-s ing contact, however, comprises the bridging member secured at its central portion to the operating rod 25 and having the con tacts 51 pivoted to the respective ends thereof. As illustrated, the ends of the bridging member are turned up at right angles and the adjacent portion of the contact extends parallel to the bridging member-or substan tially so. A loop is thereby formed at each end of the bridging member. While the switch is being moved to open circuit position the electromagnetic effect 'ofthese loops is to cause the cooperating contacts to remain in engagement with each other as long as the instantaneous value of the currentwave is not at or near zero. force of the current on each contact is opposed by the spring 52 which connects the bridging member and contact mechanically though preferably not electrically, the spring.

being suitably insulated at one end. Springs 53 between the same members serve to cuslnon thecontacts and insure good connection when the switch is in closed position irrespective of the current passing there-through. During the opening movement of the switch the main contacts first separate shunting the entire load current through the arcing contacts as in thepreviously described form;

The electromagnetic force of the current in small ar c that may occur at this time. is quick- 1y expelled into the arc chute and extinguished as already described, The movable contact also iscovere'd by cool-insulating liq- The electromagnetic uid as already described which prevents a re-establishment of the arc.

My switch has been used to break currents up' to a dead short circuit at voltages ranging from approximately 15,000 volts to 96,000

volts. The latter voltage represents the highest available voltage within the limits of the testing apparatus then available and at this high voltage. the-switch showedno signs of distress. with-a multiple break switch. The arrangement for extinguishing the arc is so effective that the average break for these tests was within approximately one half cycle ofi a twentyfive cycle wave and with an approximate break distance of only about two inches -when the arc was interrupted, although the switch utilized on these tests did not embody the means on the movable contacts. for ensuring final separation of the contacts at or-nearthe 'zero value of the current wave.

Although I- have particularly described my invention in connection with a multiple break switch having a plurality of pairs of arcing contacts, it is apparent that a switch comprising merely a single pair of breaks is within the scope of my invention. Since the 'multiple break switch isin effectmade up of a plurality of units, it is apparent that the illustrations in Figs. 1, 3 and 6, for example, serve. sufficiently toillustrate the single pair of breaks. 1 I prefer to arrange the arc chutes to expel the arcs and gases laterally in opposite directions and one advantage of this arrange #11 ment is that the reaction forces are balanced. A further advantage is that the hot gases are directed away from the main contacts and the operating rod. I

While the various features of my invention cooperate to produce a peculiarly efficient circuit breakingapparatus it will be apparent to those skilled in the art that certain features of my invention are advantageous whether or not others are used and that various changes and modifications maybe made These results were obtained without departing from my invention and I therefore aim in the "appended claims to cover all changes and modifications within the true spirit of myinvention.

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

1. Apparatus for interrupting an alternating current at or near the zero value thereof comprising cooperating fixed and movable contacts, conducting means forming a loop in circuit with the contacts including a movable portion arrangedto control the separation of the contacts, and means for yieldingly opposing the electromagneticeffect of the cu'rrent in said loop.

2. Apparatus for interrupting an alter-. nating current at or near the zero value thereof comprising cooperating fixed and movable contacts, conducting means including a mov 1 able member forming aloop in series with said contacts for controllin the separation thereof and a spring engaging the movable loop.

' 3. Apparatus for interrupting an alternating current at or near the zero value thereof, comprising cooperating fixed and movable contacts, conducting means in circuit therewith including a movable portion arrangedto control the separationof thej c0ntacts,'and' a blow-out coil for an are drawn between said contacts arranged to affect said movable portion. v v

4. Apparatus for interrupting an alternat ing current at or nearithe zero value thereof comprising cooperating fixed and movable contacts, an operating member for the movable contact having a loose mechanical connection therewith and ineans responsive to a predetermined low instantaneous value of the current for making said connection fixed.

5. Apparatus for interrupting an-alternating current at or near the zero value thereof comprising cooperating fixed and movable 7 contacts, a member for movingv the movable contactto open circuit position, means constructed to connect said member with said movable contact, and means responsive to the instantaneous values of the current for rendering said means inoperative While the greater than a predeterm ned 1ow.-

current is value.

6. Apparatus for interrupting an alternatin g current at or near the zero value thereof, comprising cooperating contacts, a mem- 1 her for-moving oneof said contacts from the other, a clutch connection between said member and said one contact, and means respons'ive to the instantaneous values ofsaidcurrent for c'ontrolling said-clutch connection. 7. Apparatus for interrupting an alternat ing current at or near the zero value thereof comprising cooperating fixed and movable contacts, an operating member, a clutch con- I nection between said member and said movable contact, and means controlling said con-.

-' I comprising cooperating fixed and movable.

nection forming a loop traversed by said current. I 8. Apparatus for interrupting-an alternating current at or near the zero value thereof contacts, an' operating member for the movable contact having a slidin mechanical connection therewith, means or yieldingly maintaining the movable contact in engage- I 'ment with the fixed contact when the instantaneous value of the current is above a predetermined amount and for connecting together the movable contact and the operat containing insulating liquid, a contact housing supported in said liquid having a pluing member to cause a separation of thecontacts when the instantaneous value of the current reduces amount.

of a loop in the circuit.

to said predetermined 9. An electric switch comprising a fixed contact, a cooperating movable contact, an operating member having a sliding connection withv the movable contact, resilient.

means for maintaining the contacts in engagement with each other when the operating member is operated, clutch means for securing the movable contact to the operating member, and a clutch controlling arm forming a portion of a loop in the current circuitthrough the switch.

, 10. An electric switch comprising a pair of fixed contacts, a bridging member having contacts slidably mounted thereon for engaging the I fixed contacts, ratchet mechanism for. connecting the bridging memberv to the contacts carried thereby, ratchet controlling arms pivoted to the bridging member adja-' cent each slidable contact, and means conmeeting said arms incircuit with the slidable contacts whereby each arm forms a portion.

11.- An electric s itch comprising a fixed contact. immersed 111 insulating liquid, a structure associated therewith, forming a- 'magnetic arc blow-out, and a blow-out chute therefor, a cooperating movable contact, and members in said chute connected respectively with said contacts to which member an are drawn between the contacts is adapted to be in insulating liquid, a structure associated with the fixed contact forming a magnetic blow-out and a blow-out chute therefor, said chute being closed on all but one side and having an opening on one side through which the movable contact is withdrawn, said blowout coil being arranged toexpel the arc in a direction substantially at right angles to the direction of movement of them'ovable con-v tact. 4

13. An electric switch comprising a vessel containing insulating liquid, a contact housing supported in said liquid having a plurality of chambers open at one side thereof,

a pair of relatively movable contacts arranged to separate iii-each of said chambers,

means connecting said pairs of contacts in open sides of the chambers any arcs drawn between the contacts, said chambers hav ng POItlODS forming reservoirs from which in-' series, and means for expelling through the sulating liquid flows to cover one of the"-con-.

tacts after the arc has been expelled there- F from. 7

l4: An electric switch comprising a vessel rality of chambers open at one side thereof,

a pair of fixed and movable contacts arranged pelled therefrom to separa'te in each ofsaid chambers, means Y connecting the pairs of contactsin series, means'for expel 'ng' throughthe open sides. of the chambers any arcs drawn between the 5 contacts; each of said chambers bein formed at,,that portion opposite the open si e-there'- of with a ocketforming a reservoir from which insu at'ing liquid flows to cover the movable contact after the arc-has been ex- 15. An electric switch comprising a vessel containing insulating liquid, acontact housing supported in the liquid having a discharge opening atone-side thereof, a fixed 16 arcing contact and blow-out coil therefor mounted in the chamber, a cooperating mov-' fable arcing contact, mean's connecting'said blow-out coil and contacts in aseries clrcuit, a fixed main current-carrying contact se- 20 cured tothe exterior of the housing, a movable main current-carrying contact, and an operating rod for the movable main and areing contacts, the opening of said chamber being arranged to direct a discharge away from.

p the operating rod and the main contacts.

16. An electric switch comprising a vessel containin insulating liquid, a air of contact housings supported in the, iquid' each I ofsaid housings comprising a plurality-of similar chambers having dischargeopen-ings at the same side of the. housing, a blow-out coil and a fixed arcin contact in each. charm ber, an o crating ro movable arcing contacts carried thereby, and cooperating main current-carrying contacts said operating rod.

a and main'current-carr ing contacts being arranged between said ousings and the discharge openings of said chambers being .ar-

ranged; to direct the discharge therefrom in 40 opposite directions and away from the operating rod and main contacts.

In witness whereof, I have hereunto set my hand this 21st da of December, 1928.

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