US1670227A - Oil-immersed electric switch - Google Patents

Description

May l5, 1928.

w. ANDERSON OIL IMHERSED ELECTRIC SWITCH Fi1e51Nov-22', 1926 4 sheets-sheet 1 May l5, 1928.

w. ANDERSON on. IMMERSED ELECTRIU swITcH* f Filed Nov. 22, 1926 4 Sheets-Sheet 2 May l5, 1928A.

w. ANDgRsoN OIL IMMERSED ELECTRIC SWITCH Filed Nov. 22, 192e 4 sheets-sheet 5 May 15, 1928.

w. ANDERSON OIL IHMERSED ELECTRIC SWITCH Filed NOV. 22, 1926 4vShe8tS-Sh6et 4 Patented May 15, 1928.

UNITED sTATEs 1,670,227 PATENT OFFICE.

WILLIAM ANDERSON', OF HEBBURN-ON-TYNE, ENGLAND, ASSIGNOB TO A. BEYBOLLE COMPANY LIMITED, OF HEBBURN-ON-TYNE, ENGLAND, A COMPANYOF GREAT BRITAIN'.

OIL-IMMERSED ELECTRIC SWITCH.`

- bodily away from the gases which rise through the oil. Thus the arc is preferably moved bodily downwards through the oil either after it has been drawn out by the separation of the contacts or while it is be- ',15 gfgrawn out thereby.

e movement of the arc may be brought aboutv in various ways. Thus thearcing contacts may rst move horizontally away from one another tb draw out the are and may 2.0 then both move vertically downwards carrying the arc with them. Again one of the contacts may be xed, the other contact first moving horizontally away 'therefrom and .then swinging downwards with a pivotal motion about the fixed contact.

The horizontal and vertical movements of the contact or contacts are preferably combined together to take place simultaneously, so that the arc is moved bodilyas it is being drawn out. In this case the arcing contacts may be arranved to move downwards as'they separate 7from one another. Thus they may be mounted respectively on pivoted `arms which swing downwards and outwards away from one another when the switch opens. i

The eiliciency of the arrangement according to the invention is believed to be/due to the action of forcing the arc against a body 4o of oil and thereby quenching 1t, this action ence to a preferred construction.

It will be understood that the'arcing conadditional to main contact brushes. In the I latter case the brushes may be se arately carried-and mayi have a motion iiferent from that of the arcing contacts. Thus for example when the arcing contacts are carried on pivoted arms which swingoutwards and downwards, the main,contacts may comprise' two fixed contact membersand a vertically movable brush-member. Alternatively the u main contact brushes may also be carried on being more fully described below with refer? 150,040, and in Great Britain January 8,'1926.

the pivoted arms which carry vthe arcing contacts. Various other arrangements cof. separate main contacts and arcing contactsy may also be employed. In all such cases the main contacts would be arranged to open shortly before the arcing contacts, so that the latter carry the full current only for a very brief interval. 4

The invention may be carried into ractice in various ways and is applicable oth to D. C. and to A.. C. switches.

In the accompanying drawings, j

Figure I is a sectional elevation of one practical construction of oil-immersed switch according to this invention,

Figure 2 is a section on theline' 2.-2 of Figure 1,

Figures 3 and 4 are views generally similar to Figure 1 but showing the switch conliaactls just opening and fully open" respecive y, Y

Figure 5 is an elevation vpartly in section on the line 5 5 of Figure 6 of another construction of oil-immersed switch also according to Ythisv invention,

Figure 6 is` a section at right angles to Figure 5, and

Figures 7 and 8 are elevations partly in section on .the line 7-7 of Figure 6, Figure 7 showing the contacts just opening and Figure 8 illustrating the fully open position.

All the figures are somewhat diagrammatic, details of construction not essential tothe understtanding o f the invention being omitted.' 'i

With reference first to Figures 1 and 2, A is the oil tank 'having mounted within it two rock shafts B and B1. The shaft B carries two main contacts of which one'is shown at C (Figure 1) and the shaft B1 carries two cooperating .main7 contacts C1 and C (Fig- J pure 2) It will be understood that the other tacts above referred to may themselves bei 45 the main contacts of the switch or may be 'main contact carried by the shaft B is similar to the contact C. The contact arms are insulated from the shafts and the two main contacts C1 and C carried bythe shaft B1 .are connected to plugs, one of which is .indiswtch has two main breaks in series with each other. Each of the main contact arms 11| 5 5 To'release :ill but C10? carries an auxiliary or rcing contact E cooperating with other arcing contacts E1 pivotally mounted on the main contact C and on the other corresponding main contact 5 mounted on the shaft B. These arcing contacts are' normally pressed by springs E2 intdengagement with the contacts E, the movement being limited in any suitable way. Y For convenience and brevity the Jurther description will refer only to one cooperating pair of main contact-arms, i..e. the'contact arms C and C1 of ,Figure 1, for it will beV appreciated that the 'other' pair is precisely similar and will operate in the same Way Each ofthe shafts B and B1 has a crank F mounted upon it joined by a link F1 to a rod'F2 carrying a piston orhea'd Fs workirg.`

in 'aJ cylinder F5 and a kick-ofi spring- 4 tendsto push the rod F2 downwards to rock 'the shaft and open the, switch contacts.

TheV mechanism for holding 'the contacts closed, for resetting and for'reclosing them is shown in various positions in Figures 1, 3 and 4. The upper ends of the rods F2 are joined b links' F8 to the arms of pivoted bell cran levers G G1 which are coupled by a link H. The bellicrank lever G-1 has an extensionG2 connected/through a pivoted link `G3 tothe top cfa long link or connecting rod J, the lower 'end of this rod being p'ivoted to a crank K on a spindle K1 which can be partially rotated by means of a hand wheel K2 .and bevel gear K,

' 35 Actually there are two rods J' as shown in Figure 2 but that detail is immaterial# At a point J1 (Figure) distan from the'top of the rod` J by alength equal to that of the l' G3 a link L is pivoted to the rod J, i0' its ot er end beingjolned through a link L1 to the pivotal spindle of the bell crank lever G1. The links L and L1 form atoglgle which when setretains` the other parts of the mechanism in the desired relative position. M isa fixed stop which prevents rotation of' the crank K in a clock-wise direction beyond a-predetermined'rpoint In the closed position shown 1n Figure 1 the` springs F are tending to force down the 'rods Fz but they cannotA do soas the toggle L \L1 'is in its set position and the upper end of the rod J cannot swin jout-I wards; thus the bellA crank G1 cannot rotated. Y

the switch and allow it to open the toggle L L1 is broken, as f orinstanc'e by being pushed up by the triplping electrol magnet N.4 This allows the ro J to swing u out and onsequently the bell crank G1 can 69 rotatef lgure 3 shows the position of the v'parts just after the trip has occurred.

. The rods F continue their rapid downward notlon and the contaets-assumetheir 'fully Iopen position as shown in-Figure 4 as, yet the'crank K and J remain nemen? Uthe -piston'or head AF just as it reaches thewhen a single'moving contact is used.y

practically in the position shown in Figure 3.

Resetting of the mechanism ready for reclosing is raccomplished by rotating the crankI K counter-'clockwise from the position of Figure 3 to thatof Figure 4. This motionbrings the link Gra parallel with .the rod J' and sets the toggle L L1 again and rotation of the Vcrank K clock-wise back until it meets the stop M brings'all the parts back to-the closed position of Figure 1.f

In order to bring the moving parts quickly to rest inthe open position a\ hole F in the wall of the cylinder F5 is closedby limit of its downward movement. l Dealing now with the motion of the c ontacts themselves, it will be seen that the 1n1- tial opening movement first separates the main contacts C C1 but momentarily the arcing contacts E E1 remain closed as shown in Figure 3. Furthermovement separates the arcin'g contacts and draws the are rapidtly outwards at the same time moving it down quickly away from gas bubbles'which 90 naturally rise. TheY magnetic forces also` tend to force the arc downwards and thus the arc is drawn rapidly .downwardsl both mechanically and magnetically away from the conducting'gas bubbles and is broken 95 over what ispractically a. solid body of oil since the inertia of the oil is too great to ad- `mit of its rapid` acceleration when confined bythe tank. The breaking of the arc is assisted bymeans of an arc. splitter 0 of refractoify insulating material projecting upwards from the ioor of the tank between the separating contacts. lThe main func- \tions of this arc splitter O are. to lengthen and cool the arc and to assist in preventing movement' of the oil with the contacts away from the arc. ySince the limiting factor for the speed of break is the cavitation which may e set up in the oil by the movement of the contact arms, it will be seenthat the 1w vemployment ,of the-two movablev pivoted arms allows nearly twice the speed Vof-break which is possible without risk ofcavitation lFigures 5, 6, 7 and 8-show another practi. ila

cal construction of switch according to this .invention intended for 'heavier currents.

The chief di'iierenee between this form and that previously described is that the arcinfg.

contacts are not carried by the main contact 12o arms but are mounted separately. f

In this construction the. movable main contact is in the form of ablock C mountedpn but insulated from a plunger rod Fa which tends to be moved downwards by a 125 kick-oli spring E" to breakthe circuit by separating the block C from two fixed mam contacts C29 Y The ageing contactsE E* Aare pivotally. mounted on arms El5 E carriedv by but in 130 vsulated from rock shafts B2 B1. Springs 1L7 tend to press the contacts Es E4 together, the motion being limited by stop pins E.

The ends of .the main contact block C3 are joined by insulating rods C5 to crank blocks B4 on the rock shafts B2 B3 so that the; downward opening movement of the mam contact causes a rapid ldownward and outward swing ofthe arms E5 E6 and the arcing contacts carried by them.

The various stages of the openin move` ,tion I) (removed for the sake of clearness in Figure 8) and an arc splitter O1 is provided. A chamber R (Figure 6) receives the ascending gas which can pass out .through vent pipes R1.

. The mechanism for resetting and reclosing need not be described in great detail as itis substantially the sameas that described with reference to Figures 1,2, 3

and 4.l The top of the rod F8 is linked to a pivoted cross head Gr4 joined by a link Gr5 to the top of a rod J2 and the top of that rod is joined by a toggle link L2 Ls to the pivot of the cross head. The rod J2 is in this construction divided or compound, its upper part being connected to its lower part by a spring J3 (Figure 6) serving .to-provide a yielding contact between the moving block C3 land the xed block C4, The lower end of the rod J2 -is pivoted to a crank K1 operated through gear K5 by a hand wheel K.

The two rock shafts B2 B3 are shown. as

coupled by a rod B5 but this coupling is not essential if each of the-shafts is connected to the block C3 as at C.-

In this construction also some' provi-sion is preferably4 made for bringing the moving parts quickly to,rest and as will be v seen from Figure 6 a tapered plug F1 on sulating layer F11, and the Itv'vo vfixed lmain contacts C are clamped together around this insulation F1l by means of insulated i bolts C.

. It is to be understood that the foregoing description has been given b way of example only and that considerab e modiiications in detail may be made without departmg from the scope of the invention.

What I claim as my invention and del sire to secure by Letters Patent is A l. In an electric switch the combination of a tank adapted to contain oil, rock shafts iniisaid tank, arms, mounted on said rock shafts, arcing contacts mounted on said arms, fixed and movable main contacts in said tank, an insulatingpartition in Said tank between sa-id arcing contacts and said fixed and movable main contacts, a spring tending to separate said movable main contact from the fixed main contacts, a toggle linkage operating to hold the main contacts closed against the action of said spring, a

trip devicefor breaking said toggle linkage and allowing the spring to operate, an o erative connection between said movab e main .contact and said rock, shafts, such o erative -connection acting to rock the sha ts immediately after the main contacts are broken and thus to swing the arms and arcing contacts downwards and outwards, and an arc splitter in the path of the arc as it is moved downwards and drawn out between said arcin contacts.

, 2. In an Aelectric switch the combination of a tank adapted to contain oil, rock shafts in said tank, arms mounted on said rock shafts, arcing contacts mounted on -said arms, fixedl and movable main contacts in said tank, a spring tending to separate said movable main contact from the ixedmain contacts, a toggle linkage operating to hold the main contacts closed against the action of said spring, a trip device for breaking said toggle linkage and allowing the spring to operate, an operative connection between said movable main contact and said rock shafts, such operative connection acting to rock the shafts immediately after the main contacts are broken and thus to swing the arms and arcing contacts downwards and outwards, an arc splitter in the'path of the arc as it is moved downwards and drawn out between said arcing contacts, and dash-pot mechanism for bringing the moving contacts quickly to rest.

In testimony whereof I have signed *myr lname to this specification.

WILLIAM ANDERSON.

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