US2677032A

US2677032A - Electric switch with permanentmagnet blowout fields

Info

Publication number: US2677032A
Application number: US233136A
Authority: US
Inventors: Bruce C Wells
Original assignee: Westinghouse Electric Corp
Current assignee: CBS Corp
Priority date: 1951-06-23
Filing date: 1951-06-23
Publication date: 1954-04-27
Anticipated expiration: 1971-04-27
Also published as: FR1066173A; GB711726A

Description

April 21, 1954 Filed June 25, 1951 B. C. WELLS ELECTRIC SWITCH WITH PERMANENT-MAGNET BLOWOUT FIELDS 2 Sheets-Sheet l Apr-i127; 1954 B. C. WELLS ELECTRIC SWITCH WITH PERMANENT-MAGNET BLOWOUT FIELDS Filed June 25, 1951 Fg.8. i

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INVENTOR Bruce C Wells.

ATTORNEY Patented Apr. 27, 1954 ELECTRIC SWITCH WITH PERMANENT- MAGNET BLOWOUT FIELDS Bruce C. Wells, Buffalo, N. Y., assignor to West-I inghouse Electric Corporation, East Pittsburgh, Pa., a corporation of Pennsylvania Application June 23, 1951, Serial No. 233,136

9 Claims. 1

My invention relates to electric switches and more particularly to switch contact devices with permanent magnets to provide an arc blowout field.

Known devices, for the kind of switch contact arrangement I utilize, provide a single relatively large electromagnet mounted so that the two .poles of the magnet are on opposite sides of the relatively movable contacts. If the arrangement is for a transfer switch where a movable contact moves in contact and out of contact with rst one stationary contact and then another stationary contact, it is apparent that the arc on opening of thev contacts will be blown rst in one direction and then in another. Such operation is highly undesirable in some applications.

Itis one broad object of my invention to effect a uniform blowout direction for an electric arc with reference to the elements of the switch structure. l

It is a more specific object of my invention to provide an arc blowout in the same direction at the contacts of a vibrating contactor.

The objects recited are merely representative of other objects and advantages of my invention that will become more apparent from a study of the following specication and the accompanying drawings, in which:

Figure 1 is a plan view of an electromagnetic contactor provided with my invention;

Fig. 2 is a side view, partly in section, of the subject matter shown in Fig- 1;

Fig. 3 is a plan view of an arc chute construction of a contacter provided with my invention;

Fig. 4 is a vertical sectional view, on line IV-IV of the showing in Fig. 3;

Fig. 5 is a horizontal sectional view, on line V-V of Fig. 4;

Figs. 6 and 7 are schematic showings of a switch, shown in plan view and side elevation, respectively, provided with my invention;

Fig. 8 is a modication oi -my invention; and

Fig. 9 is a diagrammatic showing of the kind of blowout efectproduced by the devices of the prior art.

In Figs. 1 and 2, I have shown a switch construction well known in the trade but modiiied to eliminate the blow-out electromagnet and further Inodied to provide a pair of permanent magnets I6 and I1, one at each side of the contact mechanisms, including the horizontally adjustable stationary contacts H and I2, and the movablemccntact I0.

The structure comprises the base I of insulat inc material carrying the contactor base 2 also of insulating material. At the lower end of base 2 the U-shaped magnet'l 3 is mounted. This U- shaped magnet carries the

coils

4 and 5 on the cores or. legs of the U. The

coils

4 and 5 when energized and in cooperation with the U-shaped magnet operate the armature 8 in a clockwise direction. The armature 5 is mounted on the contact actuating arm I pivoted at 8 and biased in a counterclockwise direction by the spring 9.

The upper end of arm 'I carries the movable contact In adapted to make Contact either with stationary contact II or with stationary contact I2, depending on whether the coils II and 5 are energized or deenergized. The contacts Iil, II,

; andv I2 are disposed within the arc box I3 having tacts III, IIO and II2, the arc between contacts IIB and III is blown upwardly, as shown by arc IIlI, but the arc |02 between contacts IIU and I I2 is blown downwardly. For most switches,` there.

are elements belowl the contacts that are not to be subjected to an arc, or, what is usually worse and citen the case, the elements below the contacts tend to maintain the arc. For still other switches, especially` where considerable currents are to be interrupted special arc extinguishing grids are provided above the contacts, as shown in Figs. 3, 4, and 5. If the arc is blown downwardly,ksuch arc extinguishing grids are oino utility. To obtain the full benet from the arc boxes provided on somecontactors, and the are extinguishing grids provided on'other contactors, I utilize an elongated. permanent magnet I6 at one side of the contacts I0, II, and I2 and a second elongated permanentmagnet I'I at the other side ofthe contacts. The disposition is such that the north pole of one magnet is opposite the south pole of the other magnet, and the south pole of the iirst magnet is opposite the north pole or" the second magnet, with the magnet ends facing each other substantially in the planes of the pair K of stationary contacts Il and I2.

With the arrangement just described the flux lines will be as shown in Figs. 6 and 7. It will be noted that the lines move clockwise about contact ZID as seen in Fig. 6 so that theY arc is blown upwardly between contacts 2I and 2li and is 3 blown upwardly between contacts El and 2I2. Contacts 2 I t, ZI I, and 2 I 2 correspond to the contacts It, Il, and I2 shown in Figs. l and 2, and correspond to contacts 3i). 3l, and 32 in Figs. 3, 4, and 5.

In Fig. 8, I show the permanent magnets in the general shape of a U with the stationary contacts 3H and 3I2 disposed between the legs` of the U and the movable contact 3H) disposed to oscillate between the stationary contacts 3|! and l ill The arrangement shown in Fig. 8 has special merit for some applications wherethe magnetic air-gap is to be maintained at a minimum. In the showing of Fig. 8 the permanent magnet 3I6 need not necessarily,7 be insulated from contact 3 II nor does the permanent magnet 3I-I need to be insulated from contact 3I2. The magnets are thus'notrin position -to providea spurious arc path. The poles 4of the `magnets may thus be in close` proximity to the stationary contact and thusuprovide a better space factor for the transfer switch design.

In Figs, 3, 4, and 5, -I show an arc extinguishing grid 33. associated with the contacts 30, 3|, and 32; To getthefull benefit ofthe arc extinguishing'grid, I position the permanent magnet 3% at onefsidegof the gridand the permanent magnet 3l at the other side of the Igrid and position the ends ofthe magnets and their polarities in the same relation as explained connection with Figs. l 1 andb 2.y

Withfthe modern typeof permanent magnets availablethere is no` danger of not having suiiicient iux.l

From the` foregoing ity-will be apparent that I havey provided a permanent magnet blowout construction, iorl an oscillating contact type of contactor, thateiiectsa blowoutuin the same direction., `regardless `Aci which contacts are going through the. precios. operation.-

While'HI-have shovvnubutjtwo ,applicationsnofy L" my inventioniother applications and other modications of myinvjention are well within the true spirit Y and scope of y my invention.

I @amasar invention.:

1. i anyelectric switch, in combination, a base, a Stationary QQIltat mounted onth base. a Secondmstationary contactmounted on the base a relativelyushort distancegfrom the first stationary contact a Amovable Contact disposed between the statjioriary contacts andpperabletc oscillate betweertthe.Contactst0;;i1iterrupt ell-,electric Crcuit `at "one stationarypontact vand close an electric circuitat the otherstationary contactnpon movement of the `movable contact in one direction and to eiectla similaroperation with'respect tothe secondandirststationary contacts upon movement of the movable contact in `an opposite direction whereupon-angelectric arc is alternately drawnfbtween 'the movable, Contact and .the` respeotivestationary ,contacts, `a `permanent magnet disposedwithV its north poleadjacent one side" of the contacts; `and a second permanent magnet adjacent` the other side of the contacts with thepoleswof opposite signffacing each other substantially across lthe faces of the stationary contacts, whereby the arc drawn at the contactsv is `always blown inthe same direction.:

2. In an electricswitch, thencombination ofa movable contact disposed between a pair of-sta tionary contacts for coaction with the movable contact, a pair of permanent magnets disposed at the respective sides of the contacts with the poles so disposed that the flux s disposed across one face of the stationary contact in one direction and across the face of the other stationary Contact in the oppositeldirection.

3. In an electric switch,the'combination of, a pair of stationary contacts disposed to face each other across a relatively short distance, a movable contact disposedbetween the stationary contacts and operable to oscillate to thus alternately engage the stationary contacts, a pair of permanent lmagnets disposed one at each side of the contacts with-the poles so disposed that the flux produced by the magnets encircles the movable contact.

4. In an electric switch, the combination of, a pair of stationary contacts disposed to face each other across a relatively short distance, a movable contact rdisposedbetween' the stationary con tacts and operable to `cscillate to thus alternately engage .l the stationary i contacts, an arc box. of insulating material disposed to confine the arcs that may be drawn atthe contacts, a pair of permanent magnets disposed one at. each side ofthe y contacts with the poles so disposed that the flux producedby the magnets encircles the movable contact.

5. In an electric switch,.the combinationiofya pair of stationary contactsV disposed to face each'l other across a relatively short distance, a movV able contact disposed betweenthe stationary contacts and operable to oscillate to thus alternately` engage the stationary contacts, an -arc box. offin- Sula-ting material disposedtoconne the arcs.

that may bev drawn at the contacts, are vextin-` guishing grids-in the arc box,` a pairof permanent magnets disposed one at each side of the contacts ywith the poles so disposed that the flux produced by the v-magnets-encircles .the movable contact.

6. In an electric switch,` the combination of, f

a pair of relatively Kclosely spaced stationary Icontacts, -a movable Contact disposedv between- -the stationary contacts and operable to engage one or the other of the stationary contacts, a permanent magnet at one side of the contacts-'having a lengthsuiicientthat theY poles are substantially opposite the stationary contacts, and af second permanent magnet similar in length and so disposed on the opposite sides of the contacts i with poles of-opposite polarity facing each other acrossthe face of the stationary Icontacts and that the arc drawn at the contacts is blown 4upwardly.

'7. yIn an-e1ectric switch.v the combination of,

a pair of relatively closely spaced stationary con tacts, a movable contact disposed between the stationary contacts and operable to engage one or the other of the stationary contacts, a permanent magnet at one side` of thevcontacts having `a length sufcient ythat-.the po1esare-substantially opposite the stationary contacts, aA sec-` ond permanent magnet similar in length and sodisposed on `the opposite vsides of the contacts with poles of opposite polarity facing each other` across the face ofthe stationary contacts and tha-t the are drawn'at-the contacts is blown upwardly, 4and an `arc box idisposed over the foon-'1 tactsfor conningvthearc drawnat theif'contacts.

8. In an electric switch, the combination-0n a pair of relatively closelyfspacedy stationarycontacts,- `a movable contact disposedbetweenwhe stationary contacts and operable to engage one or the other of the stationary contacts, a permanent magnet at one side of the contacts having a length sufficient that the poles are substantially opposite the stationary contacts, a second permanent magnet similar in length and so disposed on the opposite sides of the contacts with poles of opposite polarity facing each other across the face of the stationary contacts and that the arc drawn at the contacts is blown upwardly, an arc box` disposed over the contacts for confining the arc drawn at the contacts, and arc extinguishing grids disposed in the box over the contacts to rapidly extinguish the arc.

9. In an electric switch, the combination of, a pair of stationary contacts disposed to face each other over a relatively small distance, a movable contact disposed between the contacts and in operation alternately icoactine,r with the stationary contacts, and magnetic flux producing means including a rst means for producing a flux in one direction across the face of one stationary contact and a second means for producing a flux in an opposite `direction across the face of the other stationary contact whereby the flux encircles the movable contact.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 2,332,446 Heinrich Oct. 19, 1943 2,372,094 Leeds Mar. 20, 1945 2,506,727 Mas May 9, 1950 2,575,060 Matthias Nov. 13, 1951