US2477810A

US2477810A - Multiple break circuit interrupter

Info

Publication number: US2477810A
Application number: US549576A
Authority: US
Inventors: Winthrop M Leeds; James M Cumming
Original assignee: Westinghouse Electric Corp
Current assignee: CBS Corp
Priority date: 1944-08-15
Filing date: 1944-08-15
Publication date: 1949-08-02
Anticipated expiration: 1966-08-02

Description

Aug. 2, 1949.

w. M. LEEDS ETAL 2,477,810

MULTIPLE BREAK CIRCUIT INTERRUPTER Filed Aug. 15, 1944 7 Sheets-Sheet 1 Jameg /W. Gum/72mg. I

ATTORN A g- 2, 949 w. M. LEEDS ET AL 2,477,810

MULTIPLE BREAK CIRCUIT INTERRUPTER Filed Aug. 15, 1944 7 Sheets-Sheet 2 WITNESSES: "gENTOgS m rap ea 5 an James M Cumming. don-F a Y A'ITORN Allg- 1949. w. M. LEEDS ETAL 2,477,810

MULTIPLE BREAK CIRCUIT INTERRUPTER Filed Aug. 15, 1944 7 Sheets-Sheet 3 INVENTORS Winthrop M. Leeds and James M Uummmg.

2, 1949; w. M. LEEDS ET AL 2,477,810

MULTIPLE BREAK CIRCUIT INTERRUPTER Filed Aug. 15, 1944 7 Sheets-Shee 4 INJENTORS Winthrop Leeds and James 011mm 272g.

1949- w. M. LEEDS ET AL 2,477,810

MULTIPLE BREAK CIRCUIT INTERRUPTER Filed Aug. 15, 1944 '7 Sheets-Sheet 5 Magnetic 4 Material Magnetic Material v INVENTORS Winthrop M Leeds and James MGummz'ng.

WITNESSES:

1949. w. M. LEEDS ETAL 2,477,810

MULTIPLE BREAK CIRCUIT INIERRUPTER Filed Aug. 15, 1944 7 Sheets-Shelet 6 I ES: INVENTORS ZQ Winthrop MLaeds andfames'fil Cumming.

Aug. 2, 1949. w. M. LEEDS ETAL 2,477,810

MULTIPLE BREAK CIRCUIT INTERRUPTER Filed Aug. 15, 1944 7 Sheets-Sheet 7 III III Ill/Ill I Y/I/l'.

\\' \\\\\\\\\\\\\\\n FIRE 105 .L' I 4 g 1o .wnussszs: INVENTORS Wimkrap M Leeds and 4%. James M Cumming.

I q a zm Patented Aug. 2, 1949 UNITED STATES PATENT OFFICE 2,477,810 MULTIPLE BREAK cmomr m'rnnaur'raa Winthrop M. Leeds, Forest Hills, and James M.

Cumming, Turtle Creek, Pa... assignors to Westinghouse Electric Corporation, East Pittsburgh, Pa., a corporation of Pennsylvania Application August 15, 1944, Serial No. 549,576

27 Claims. 1 i

This invention relates to circuit lnterrupters in general and, more particularly, to circuit interrupters of the liquid break type.

In addition to the fundamental function of interrupting its rated current capacity at rated voltage, the modern circuit breaker should have the ability to operate at very high speed (total time from energizing thetrip coil to are extinction being as low as 3 to cycles at 60 cycles frequency). Also it has been found desirable to interrupt low current values, such as magnetizing or line charging currents (usually below 25% of rating), almost as fast as short circuit currents to avoid the possibility of objectionable switching surges.

In United States patent application Serial No. 468,454, filed December 10, 1942, by Robert C. Dickinson, now U. S. Patent 2,394,046, issued February 5, 1946, and assigned to the assignee of the instant application there is disclosed and claimed a novel operating arrangement for simultaneously effecting the operation of two serially related arc extinguishing units. In this application rotatable lever means are employed to simultaneously effect the operation of two movable contact structures. It is an object of our invention to improvise an improved operating arrangement over the arrangement disclosed in this application.

Also in United States patent application Serial No. 471,847, filed January 9, 1943, by Benjamin P. Baker, now U. S. Patent 2,412,857, issued December 17, 1946, and assigned to the assignee of the instant application there is disclosed and claimed an operating arrangement which simultaneously effects the operation of a plurality of movable contact structures employing lever means to eifect their actuation. An operating rod is also utilized to simultaneously efiect the operation of the lever means during the opening operation oi the interrupter. It is an object of our invention to further improve the operating arrangement disclosed in this patent application.

Another object is to provide an improved circuit interrupter in which a plurality of serially related arc extinguishing units are employed, and to provide interconnecting passage means between the units so that pressure generated in certain units may be utilized to efiect the flow of fluid through the passage means into other units to facilitate the extinction of the arcs drawn in the other units.

Another object is to provide an improved circuit interrupter in which two are extinguishing units are employed and to provide contact means 2 operative in each unit to establish an arc. We provide rotatable actuating means for simultaneously effecting the operation of both contact means.

Further objects and advantages will readily become apparent upon the reading of the following specification taken in connection with the drawings, in which:

Figure 1 is a vertical sectional view of an arc extinguishing assemblage embodying our invention and shown in the closed circuit position;

Fig. 2 is an enlarged vertical sectional view of the upper two are extinguishing units of Fig. l, the movable parts being shown in the partly open circuit position;

Fig. 3 is a vertical sectional view taken along the line IIIIH of Fig. 7;

Fig. 4 is a plan view in section taken along the line IVIV of Fig. 2;

Fig. 5 is a plan view in section taken along the line V--V of Fig. 2;

Fig. 6 is a plan view in section taken along the line VI-VI of Fig. 2;

Fig. 7 is a plan view in section taken along the line VII-VII of Fig. 2;

Fig. 8 is a plan view in section taken along the line VIII-VIII of Fig. 2;

Fig. 9 is a plan view in section taken along the line IX-IX of Fig. 2;

Fig. 10 is a plan view in section taken along the line X-X of Fig. 2;

Fig. 11 is a schematic view of a modified type of arc extinguishing assemblage embodying our invention, the disposition of the parts being in an intermediate point in the opening operation;

Figs. 12 through 19 show plan views of plate details used in the construction of the are extinguishing units employed in Fig. 1;

Fig. 20 shows a modified type of upper arc extinguishing unit employed in the assemblage of Fig. 1, the parts being shown in the partly open circuit position;

Fig. 21 is a plan view in section taken along the line XXI-XXI of Fig. 20;

Fig. 22 is another modified type of upper are extinguishing unit which may be used in place of the upper arc extinguishing unit of Fig. 1, the parts being shown in the partly open circuit position;

Fig. 23 is an enlarged vertical sectional view taken through the modified type of arc extinguishing unit shown in Fig. 22 along the line XXIII-m1 of Fig. 24; and

Fig. 24 is a plan view in section taken along the line XXIV-XXIV of Fig. 22.

Referring to the drawings and more particularly to Fig. 1, the reference numeral I generally designates an arc extinguishing assemblage which may be suspended in a tank 2 (Fig. 11) by suitablemeans well known in the art. An arc extinguishing fluid 3, such as oil. fills the tank 2 to the level 3a thereby completely immersing the arc extinguishing assemblage I. Referring again to Fig. 1 the arc extinguishing assemblage I, in this instance, comprises three serially related arc extinguishing units generally designated by the reference numeral 4 and disposed in a superimposed spaced relation. A contact means is operative in each unit 4 to establish an arc therein. In the upper or end unit 4 the contact means comprises a stationary contact 5 having a stud portion 6 extending through the top casting plate I of the assemblage I and secured thereto by nuts 8, and a movable contact 9 having a pin I8 extending therethrough which is engaged by a rotatable actuating means generally designated by the reference numeral I I.

An identical rotatable actuating means II is disposed between the center unit 4 and the lower or end unit 4. The two rotatable actuating means II efiect the operation of the two movable contacts |2,I3 operative within the center unit 4. The lower rotatable actuating means II also causes the operation of the movable contact I4 associated with the lower arc extinguishing unit 4. Cooperable with the movable contact I4 is a stationary contact I5 secured by suitable means (not shown) to the bottom plate casting I6.

During the opening operation the several contacts are actuated by rotative movement of the rotatable actuating means II to establish an arc in each arc extinguishing unit 4. We provide fluid passage means generally designated by the reference numeral II interconnecting the three are extinguishing units 4. In this instance the fluid passage means I1 comprises conduits I8 formed in a casting I9 disposed between the center unit 4 and each end unit (see Figs. 3 and 7). The casting I9 has integrally formed therewith support brackets (Fig. 7) through which passes a pin 2| pivotally supporting lever means generally designated by the reference numeral 22. In this instance the lever means 22 comprises two levers 23 pivotally supported on the pin 2| and having supported at their opposed ends pins I0 and 24. The pin 24 causes the operation of the movable contact I2 of the central unit 4, and the pin III causes operation of the movable contact 9. Forming an extension of the movable contact 9 is a piston member 25 which moves into and out of central unit 4 during the opening and closing operation, the purpose for which will appear more clearly hereinafter. Also associated with the movable contact I4 is a piston member 26 which moves into and out of the central unit 4.

The two rotatable actuating means II are simultaneously operated by vertical reciprocating motion of two insulating operating rods 21 which are actuated by the vertical reciprocating motion of the conducting bridging member 28, the latter electrically interconnecting the two are extinguishing assemblages I disposed in the tank 2 connects the member 38 with the plate casting I6.

contact I2, movable contact I3, conductor 33,

movable contact I4, stationary contact I5, plate I6, conductor 32, member 30, disconnect fingers 3|, through the conducting bridging member 28 and finally through the right-hand arc extinguishing assemblage I in an identical manner to the right-hand terminal stud not shown.

The operating rods 21 have clamped thereto brackets 31 (Fig. 7) which support pins 38 which also pass through the levers 23 to cause the actuation thereof. It will be observed, referring to Fig. 1,. that the pin 38 associated with the upper rotatable actuating means I I is to the right of the pin 2|, whereas the pin 38 associated with the lower rotatable actuating means II is disposed to the left of the pin 2|. Consequently, during the closing operation the upper actuating means II causes a counterclockwise rotation of the lever means 22, whereas the lower actuating means II causes a clockwise rotation of the lower lever means 22.

The construction of the arc extinguishing unit 4 will now be described. With reference to the central arc extinguishing unit 4 it will be observed that immediately below the casting I9 is an insulating plate 39 having a configuration more clearly shown in Fig. 15. The plate 39 has two apertures 40 formed therein for the accommodation of insulating tie rods 4| (Fig. 10). The tie rods 4| function to maintain the plates fixedly in position and extend through all of the units 4. Additional tie rods 42 (Fig. 1) composed of insulating material extend between the plates I and the plate It exteriorly of the units 4 and nuts 43 secure the rods 42 to bosses 44 integrally formed with the plates I and I6.

The insulating plate 39 (Fig. 10) also has two apertures 45 formed therein through which loosely pass the operating rods 21. Apertures 46 are provided in the plate 39 to help form the fluid passage means II. An aperture 47 is provided to accommodate the motion of the piston member 25. An aperture 43 is provided to accommodate the movable contact I2, the aperture 48 communicating with a cutout portion generally designated by the reference numeral 49 and forming four pockets 58. Below the plate 39 is a second plate 33 which is followed by a magnetic insert plate group generally designated by, the reference numeral 5|.

The plate group 5| comprises a group of three plates, the outer two of which are designated by the reference numeral 52 (Fig. 16) and are herein called guard plates. The insulating guard plates 52 (Fig, 16) have

apertures

48, 45, and 46. The guard plate 52 has formed therein a cut-out portion 54. Between the insulating guard plates 52 is an insulating magnetic insert plate 55 having a configuration more clearly shown in Fig. 17. The insert plate 55 has the

apertures

48, 45, 46 and 41 with a cut-out portion defined by the outer full line 56 in Fig. 17. Positioned within the cutout portion 56 is a U-shaped insert 51 composed of a magnetic material, in this instance iron, the purpose for which will appear more clearly hereinafter. Positioned within the magnetic insert is an insulating liner plate 58 having a thickness equivalent to the thickness of two of the guard plates 52 and one insulating plate 55. Consequently, when the insert plate 55 is positioned between two insulating guard plates 52 the thickness of the liner plate 58 is suflicient to extend through all three plates.

The liner plate 58 has an aperture 48 formed therein to accommodate the movable contact l2 which communicates with the cut-out portion 59. Referring to Fig. 2 it will be observed that below the magnetic insert group 5| is a third plate 39, which is followed by a second group 5|. Below the second group 5! is positioned an insulating flow plate 60 having a configuration more clearly shown in Fig. 19 of the drawings. The plate 60 has

apertures

40, 45, 46, 41 and two connecting passages 53. The plate 66 also has an aperture 48, cut-out portion 43 forming four pockets 56 and leading by a passage 6| to the aperture 41.

Referring to Fig. 2 it will be noted that below the flow plate 60 is a group 5|, a second flow plate 60, group 5|, two iiow plates 66, group 5|, plate 60, group 5|, plate 60, group 5|, plate 39, group 5|, and two plates 39. It will consequently be apparent that the plate grouping above and below the line 62 is symmetrical.

The interrupting structure associated with the end units 4'will now be explained. Immediately below the top casting plate I are two insulating plates 63 having a configuration more clearly shown in Fig. 12 of the drawings. Each plate 63 has

apertures

40, 45, 46, an aperture 64 to accommodate the stationary contact 5. The aperture 64 leads by way of the passage 65 to a cut-out portion generally designated by the reference numeral 56 forming four pockets 56 and leading by way of a passage 61 to an aperture 68. Below the two plates 63 is a magnetic insert plate group generally designated by the reference numeral 69. The group 59 comprises two insulating guard plates having a configuration more clearly shown in Fig. 13 and a magnetic insert plate H composed of insulating material and having a configuration more clearly shown in Fig. 14 of the drawings. The plates 10, II have

apertures

40, 45, 46. The guard plate 10 has a cut-out portion 54 and the magnetic insert plate H has a cut-out portion 56 in which is positioned a magnetic insert 51. An insulating liner plate 12 is provided having a thickness equivalent to two guard plates 16 and one insert plate H. The two plates 16 and the plate H are assembled in a manner as previously described.

Referring to Fig. 2 it will be noted that below the plate group 69 is a third plate 63 which is followed by a plate group 63, plate 63, plate group 69, plate 63, plate group 69. Below the last mentioned plate group 69 are two insulating plates 13 having a configuration more clearly shown in Fig. 18 of the drawings. Each insulating plate 13 has

apertures

40, 45, 46, 64,

passages

53, 65, cutout portion 56, forming four pockets 50, a passage 61, leading to an aperture 66.

Referring to Fig. 2 it will be observed that below the second insulating flow plate 13 is a group 69, insulating flow plate 13, group 69, flow platev'l3, group 63, plate 63, group 69 and two plates 63. The interrupting structure associated with the lower arc extinguishing unit 4 is identical to the interrupting structure associated with the upper arc extinguishing unit 4 and therefore need not be described.

The operation of the arc extinguishing assemblage I will' now be described. When it is desired to open the electrical circuit passing through the interrupter, or in response to overload conditions springs 29 to force the member 30 and hence the insulating operating rods 21 downwardly. The

" downward movement of the operating rods 21 causes the operation of the two rotatable actuating means ii to effect thereby a separation of the contact means associated with each of the units 4. The result is the drawing of a pressure-gen-' erating are 14 between-the contacts l2, I3 in the center unit 4 and the drawing of two interrupting arcs 15 in the two end units 4, as more clearly shown in Fig. 2. Simultaneously the

piston members

25, 26 enter the central unit 4 to apply pressure to assist low current interruption when the pressure generated at the pressure-generating arc 14 may not be sufficient to establish the requisite velocity of oil flow adjacent the two interrupting arcs 15 to effect their extinction.

The magnetic field about the pressure-generating are 14 is distorted by the presence of the magnetic inserts 51 associated with the groups 5| to consequently cause the lateral motion of the pressure-generating are 14 to the right as viewed in Fig. 2. The rightward motion of the pressuregenerating are 14 causes it to move into the cutout portion 49 (Fig. 19) to engage additional oil retained in the pockets 50 disposed in the insulating plates 60 and plates 39. This increases the pressure established at the pressure-generating arc. The pressure thus generated by the pressure-generating are [4 acts through the passages 6| provided in the plates 60, through the passages 53 associated with the plates 66 and upwardly and downwardly through the conduits l8 as more clearly shown in Fig. 3.

Considering only the upward flow of fluid through the conduits l8 associated with the upper casting I9, it will be observed that the oil flows through the passages 53 provided by the plates I3 to engage the upper interrupting arc l5 and to pass out of the upper unit 4 by means of the vent opening 15 formed by the apertures 66 provided in the

plates

63, 10, H and.'l3. The direction of the oil flow is as indicated by the arrows in Fig. 2. A similar action takes place in the lower arc extinguishing unit 4.

It will be observed that not only is the interrupting are 15 subjected to an oil flow passing through the passages 53 of the plates 13, but also the interrupting are 15 is magnetically moved to the left as viewed in Fig. 2 by the distorted magnetic field thereabout as effected by the presence of the magnetic inserts 51 associated with the groups 69. The combined effect of the oil flow and the magnetic reaction moves the upper terminal of the interrupting are 15 onto the arcing horn H to permit the are 15 to be rapidly lengthened. The oil passes out of the upper unit 4 through a recessed portion 18 formed in the plate 1.

As mentioned previously during low current interruption the piston action caused by the

piston

25, 26 entering the central unit 4 creates the requisite oil flow adjacent the interrupting arcs 15.

From the foregoing description it will be apparent that we have provided a novel are extinguishing assemblage comprising three serially related superimposed arc extinguishing units, the center one of which is substantially enclosed and speed of separation of the movable contacts may be greatly increased over the downward speed of the movable operating rods 21. This results because of the different lever arms R and R as indicated in Fig. 2.

The novel circuit interrupter described above has been designed to interrupt low current values, such as magnetizing or line charging currents almost as fast as short-circuit currents to avoid the possibility of objectionable switching surges, and test made on the foregoing device indicate the ability of the interrupter to interrupt with high speed short-circuit currents over a wide range of current values. Because of the lever ratio R R, the arcing contacts move with approximately twice the speed of the operating rods 21. Furthermore, since there are two movable contacts |2, '|3 moving in opposite directions in the central unit 4, the speed of the break here is twice that of the breaks in the end units 4.

If found desirable, an extra lever 23 may be associated with the stationary contact of the top unit 4 and with the stationary contact l5 associated with the bottom unit 4 to operate a second movable contact (not shown) in these end units also. A fragmentary view of such a modified type of operating arrangement together with a modified type of arc extinguishing structure is shown in Figs. 20 and 21. Referring to these figures it will be observed that an extra lever 23 is associated with a movable contact 18 which takes the place of the stationary contact 5 utilized in the structure previously described. If desired, an additional accelerating compression spring 88 may be positioned at the upper ends of the two operating rods 21. Two brackets 31 may be clamped to the upper ends of the rods 21 to rotate the levers 23 about the fixed pin 2| bymeans of the pin 38. Thus during the closing stroke the lever 23 is rotated in a clockwise direction about the pin 2| and during the opening stroke the lever 23 is rotated in a counterclockwise direction about the pin 2| to effect a more rapid lengthening of the interrupting are 15 drawn between the contacts 8, 18. In like manner the lower arc extinguishing unit 4 could be modified by the addition of an extra lever 23 to actuate a movable contact, not shown, which could take the place of the stationary contact IS.

The modified type of are extinguishing structure associated with the modified type of are extinguishing unit 8| will now be explained Referring to Figs. 20 and 21 it will be observed that there are disposed within the unit 8| a plurality of magnetic insert groups generally designated by the reference numeral 82. Each group 82 comprises three insulating plates suitably formed with an insulating liner plate having a thickness equivalent to the aforesaid three plates. More specifically, the outer plates of the group 82 have a configuration more clearly shown in Fig. 21 and may be designated by the reference numeral 83. Each of the plates 88 is of insulating material and has a portion thereof designated by the line 84 in Fig. 21 removed therefrom. Between two insulating guard plates 83 is a magnetic insert plate designated by the reference numeral 85 which has an enlarged portion designated by the dotted line 86 in Fig. 21 removed therefrom. In this enlarged portion is placed a U-shaped magnetic insert 81 composed of magnetic material, in this instance iron. A liner insulating plate 88 is employed having an enlarged portion 89 and a restricted portion 98, the purpose for which will appear more fully hereinafter. Between adjacent groups 82 are positioned insulating vent plates 8| having a configuration more clearly shown in Fig. 21. The vent plates 8| have passages 82 connecting the openings 46 with the interrupting are 15. The vent plates 9| also have vent openings 93 permitting a venting of oil from within the unit 8| to the region exterior of the unit. The vent plates 9| also form a plurality of pockets 58 which serve to retain a plentiful supply of oil adjacent the interrupting are 15 a it is moved toward the left as viewed in Figs. 20 and 21.

The operation of the modified type of unit 8| will now be explained. During the opening operation the insulating operating rods 21 move downwardly to effect a downward motion of the movable contact 9 and an upward motion of the movable contact 19 to draw the interrupting are 15 therebetween, The magnetic inserts 81 bias the are 15 toward the left. During relatively high instantaneous values of arcing current, that is during the peak of the alternating current wave, the cross-sectional area of the interrupting are 15 is too large to permit it to be biased into the restricted portion 88. It is only during relatively low instantaneous values of arcing current, that is, near a current zero, at a time suitable for interruption, that the cross-sectional area of the interrupting arc I5 is sufliciently small for it to enter the restricted portion 98 under the influence of the magnetic inserts 81. While it is in the restricted portion 98 it engages fresh oil disposed in the pockets 58 and is also subjected to a blast of oil passing upwardly through the two conduits l8, through the passages 82 and into the portions 89 and 98. The combined effect of the flow creates turbulence which effects extinction at an early current zero. The upper terminal of the are 15 may transfer to the arcing horn 11 to effect a rapid lengthening thereof. Certain features of this interrupting structure are described and claimed in a patent application filed September 18, 1942, Serial No. 458,778, by Winthrop M. Leeds and Benjamin P, Baker, now Patent 2,372,589, issued March 27, 1945, and assigned to the same assignee as the instant application. The combined effect of the oil flow and the magnetic reaction will cause the are 15 to lengthen faster than the speed of separation of the contacts 8, 18 as indicated by the dotted line 84.

Figs, 22 through 24 show a modified type of interrupting structure which may be used in modified type end are extinguishing units generally designated by the reference numeral 91. Certain features of this interrupting structure are described and broadly claimed in a patent application filed November 11, 1942, Serial No. 465,244, by Leon R. Ludwig, Winthrop M. Leeds and Benjamin P. Baker, now U. S. Patent 2,406,469, issued August 27, 1946, and assigned to the same assignee as the instant application.

In the modified arc extinguishing structure 81 the movable contact 8 separates from the stationary contact 5 to draw the interrupting are 15. Above the level indicated by the dot and dash line 88 the plates of the unit 91 merely have apertures 89 formed therein to align in forming the vent passage I88. These plates are of two types and may be designated by the reference numeral IM and I82. The plates |8| have a smaller aperture I83 than have the plates |82 at I84. Of course, the plates |8l, I82 have apertures 48 and 40 to accommodate the insulating tie rods II and the operating rods 21 respectively.

The vent passage I leads out of the unit 91 by means of a pair of openings 99a provided in two of the plates I02 and the recessed portion I8 formed in the plate 1. V

Below the level 90 in the unit 81 the plates are of three difierent types and may be designated by the reference numeral I05, I00 and I01. The insulating plates I05 have a configuration more clearly shown in Fig. 24. The plates I05 have passages I08 interconnecting the openings 46 with an enlarged opening I09. The plates I05 may be designated inlet plates. The plates I0 6 may be designated exhaust plates and having a configuration indicated by the dotted line I I0 in Fig. 24, permitting an exhausting of fluid adjacent the are 15 out through a vent-passage III (Fig. 24) to the vent I00. plates I05 and exhaust plates I08 are insulating orifice plates designated by the reference numeral I01 and merely having an orifice II! of slightly larger diameter than the diameter of the movable contact 9.

During the opening operation oil passes upwardly through the conduits I8 in casting I9 to pass in the inlet passages I00 (Fig. 23) to strike the interrupting are 15 at a plurality of points as the latter is lengthened. This oil is caused to engage the arc I5 by being compelled to pass through the orifices I I! as it exhausts out of the vent passages III provided in the insulating exhaust plates I00 to the vent opening I00. Consequently, in this embodiment of our invention we provide means in at least one end unit 91 for forcing a plurality of jets of liquid at the arc drawn therein and permit an exhausting of liquid from the arc at a. plurality of intermediate points.

Referring to Fig. 11 it will be observed that we provide a modified type of arc extinguishing assemblage generally designated by the reference numeral H3 and comprising a plurality of, in this instance five, are extinguishing units 4 schematically indicated. The arc extinguishing units 4 are numbered by the Roman numerals IV. In this arrangement of five units two moving contacts operate in units II, III and IV and one moving contact in the top and bottom unit I and V. The high pressure units are units II and IV which force oil by means of the fluid passage means II into the vented units 1, III and V.

Since the middle unit III has oil forced into it from two directions, and since the contact break speed here is twice that of the speed of the break.

in the end units I, V, it should have twice as many vents as end units I, V as indicated by the four arrows I I4, whereas the end units only have venting proportional to two arrows II5.

In order to avoid high pressure in the units II and IV from acting on the pistons so as to tend to close the contacts against the opening force of the accelerating compression spring 29, it is desirable that the cross-sectional area of each piston should not exceed twice the cross-sectional area of each moving contact, since the force on two moving contacts moving out of the unit will balance the force on one piston moving into the unit.

From the foregoing description of specific embodiments of our invention it will be apparent that we have provided an improved operating arrangement for a circuit interrupter and also Between adjacent inlet improved interrupting structure to effect a breakguishing units in which one or more units are substantially enclosed and serve as pressure units to force oil by interconnecting passage means into other units of the assemblage which are vented. We have disclosed a means whereby the speed of separation of the movable contacts may be much Although we have shown and described specific structures, it is to be clearly understood that the same were merely for purposes of illustration and that changes and modifications may be made therein by those skilled in the art without departing from the spirit and scope of the appended claims.

We claim as our invention:

1. In a circuit interrupter of 'the liquid break type, an arc extinguishing assemblage comprising three serially related arc extinguishing units disposed in superimposed relation, a stationary contact disposed in each end unit, a movable contact cooperable with each stationary contact to establish an arc in each end unit, two movable contacts movable within the center unit, a first lever means interconnecting the movable contact associated with an endunit with one of the two movable contacts associated with the center unit, and a second lever means interconnecting the movable contact associated with the other end unit with the other movable contact associated with the center unit.

2. In a circuit interrupter of the liquid break type, an arc extinguishing assemblage comprising three serially related arc extinguishing units disposed in superimposed relation, a stationary contact disposed in each end unit, a movable contact cooperable with each stationary contact to establish an arc in each end unit, two movable contacts movable within the center unit, a first lever means interconnecting the movable contact associated with an end unit with one of the two movable contacts associated with the center unit, a second lever means interconnecting the movable contact associated with the other end unit with the other movable contact associated with the center unit, and fluid passage means interconnecting the three units.

3. In a circuit interrupter of the liquid break type, an arc extinguishing assemblage comprising three serially related arc extinguishing units disposed in superimposed relation, a stationary contact disposed in each end unit, a movable contact cooperable with each stationary contact to establish an arc in each end unit, two movable contacts movable within the center unit, a first lever means interconnecting the movable contact associated with an end unit with one of the two movable contacts associated with the center unit, a second lever means interconnecting the movable contact associated with the other end unit with the other movable contact associated with the center unit, and fluid passage means interconnecting the three units, the center unit being substantially enclosed, the two end units being vented so that pressure generated within the center unit will act through the fluid passage means to facilitate the extinction of the two arcs drawn in the two end units.

4. In a circuit interrupter of the liquid break type, an arc extinguishing assemblage comprising three serially related arc extinguishing units disposed in superimposed relation, a stationary-contact disposed in each end unit, a movable contact cooperable with each stationary contact to establish an arc in each end unit, two movable contacts movable within the center unit, a first lever means interconnecting the movable contact associated with an end unit with one of the two movable contacts associated with the center unit, a second units, the center unit being substantially enclosed,

the two end units being vented so that pressure generated within the center unit will act through the fluid passage means to facilitate the extinction of the two 'arcs drawn in the two end units, a piston member associated with each lever means and movable into the center unit during the opening operation, magnetic means associated with each unit to cause lateral motion of the are drawn in each unit during all instantaneous values of arcing current.

5. In a circuit interrupter of the liquid break type, an arc extinguishing assemblage comprising three serially related arc extinguishing units disposed in superimposed relation, a stationary contact disposed in each end unit, a movable contact cooperable with each stationary contact to establish an arc in each end unit, two movable contacts movable within the center unit, a first lever means interconnecting the movable contact associated with an end unit with one of the two movable contacts associated with the center unit, a second lever means interconnecting the movable contactassociated with the other end unit with the other movable contact associated with the center unit, fluid passage means interconnecting the three units, the center unit being substantially enclosed, the two end units being vented so that pressure generated within the center unit will act through the fluid passage means to facilitate the extinction of the two arcs drawn in the two end units, a piston member associated with each lever means and movable into the center unit during the opening operation, magnetic means associated with each unit to cause lateral motion of the arc drawn in each unit, and means in at least one end unit to prevent lateral motion of the arc drawn therein except only during relatively low instantaneous values of arcing current.

6. In a circuit interrupter of the liquid break type, an arc extinguishing assemblage comprising three serially related arc extinguishing units disposed in superimposed relation, a stationary con tact disposed in each end unit, a movable contact cooperable with each stationary contact to establish an arc in each end unit, two movable contacts movable within the center unit, a first lever means interconnecting the movable contact associated with an end unit with one of the two movable contacts associated with the center unit, a second lever means interconnecting the movable contact associated with the other end unit with the other movable contact associated with the center unit, fluid passage means interconnecting the three units, the center unit being substantially enclosed, the two end units being vented so that pressure generated within the center unit will act through the fluid passage means to facilitate the extinction of the two arcs drawn in the two end units, a piston member associated with each lever means and movable into the center unit during the opening operation, and means in at least one end unit for forcing a plurality of jets of liquid at the are drawn therein and permitting the exhausting of liquid from the are at a plurality of intermediate points.

a,477,ero

7. In a circuit interrupter, an arc extinguishing assemblage comprising two serially related arc extinguishing units dtsposed in axially aligned relation, rotatable lever means positioned between the two units, means pivotally'mounting the lever means intermediate its ends, a movable contact connected to the lever means adjacent one end thereof and movable within one of the two units, another movable contact connected to the lever means adjacentthe other end of the lever means and movable within the other unit, a piston member forming an extension of the second-mentioned movable contact and movable into the firstmentioned unit, and fluid flow passage means interconnecting the two units.

8. In a circuit interrupter, an arc extinguishing assemblage comprising two serially related arc extinguishing units disposed in axially aligned relation, rotatable lever means positioned between the, two units, means pivotally mounting the lever means intermediate its ends, a movable contact connected to the lever means adjacent one end thereof andmovable within one of the two units, another movable contact connected to the lever means adjacent the other end of the lever means and movable within the other unit, a piston member forming an extension of the second-mentioned movable contact and movable into the firstmentioned unit, an operating rod movable axially of the two units, means pivotally interconnecting the operatin rod and the lever means, and a conducting member for engaging the operating rod in abutting relation to cause the closing mo tion thereof.

9. In a circuit interrupter, an arc extinguishing assemblage comprising two serially related arc extinguishing units disposed in axially aligned relation,rotatable lever means positioned between the two units, means pivotally mounting the lever means intermediate its ends, a movabl contact connected to the lever means adjacent one end thereof and movable within one of the two units, another movable contact connected to the lever means adjacent the other end of the lever means and movable within the other unit, and passage means interconnecting the two units so that the are established in one of the units may force fluid through the passage meansint'o the other unit,

10. In a circuit interrupter, an arc extinguishing assemblage comprising three serially related arc extinguishing units disposed in axially aligned relation, 9. first lever means disposed between the middle and upper units, means pivotally mounting the first lever means intermediate its ends, two movable contacts connected to the first lever means adjacent its two ends, one of the contacts movable within an end unit and the other movable contact movable within the center unit, a second lever means disposed between themiddie and lower units, means pivotally mounting the second lever means intermediate its ends, two movable contacts connected to the second lever means adjacent its two ends, one of the contacts movable within the center unit, and the other movable contact movable within the lower unit.

11. In a circuit interrupter, an arc extinguishing assemblage comprising three serially related arc extinguishing units disposed in axially aligned relation, a first lever means disposed between the middle and upper units, means pivotally mounting the first lever means intermediate its ends, two movable contacts connected to the first lever means adjacent its two ends, one of the contacts movable within an end unit and the other movable contact movable within the center unit,

, 13 a second lever means disposed between the middle and lower units, means pivotally mounting the second lever means intermediate its ends, two movable contacts connected to the second lever means adjacent its two ends, one of the contacts movable within the center unit, the other movable contact movable within the lower unit, an operating rod movable axially of the assemblage, and

' means pivotally interconnecting the operating rod and the two lever means.

12. In a circuit interrupter, an arc extinguishing assemblage comprising three serially related arc extinguishing units disposed in axially aligned relation, a first lever means disposed between the middle-and upper units, means pivotally mounting the first lever means intermediate its ends, two movable contacts connected to the first lever means adjacent its two ends, one of the contacts movable within an end unit and the other movable contact movable within the center unit, a second lever means disposed between the middle and lower units, means pivotally mounting the second lever means intermediate its ends, two movable contacts connected to the second lever means adjacent its two ends, one of the contacts movable within the center unit, the other movable contact movable within the lower unit, and a piston member forming an extension of one of the movable contacts and movable within the unit adjacent to which is the unit in which the movable contact moves.

13. In a circuit interrupter, an arc extinguishing assemblage comprising three serially related, arc extinguishing units disposed in axially aligned relation, a first lever means disposed between the middle and upper units, means pivotally mounting the first lever means intermediate its ends, two movable contacts connected to the first lever means adjacent its two ends, one of the contacts movable within an end unit and the other movable contact movable within the center unit, a second lever means disposed between the middle and lower units, means pivotally mounting the second lever means intermediate its ends, two movable contacts connected to the second lever means adjacent its two ends, one of the contacts movable within the center unit, the other movable contact movablewithin the lower unit, and passage means interconnecting all three units so that pressure generated in the center unit may act through the passage means into the two end units.

14. In a circuit interrupter, an arc extinguishing assemblage comprising three serially related arc extinguishing units disposed in axially aligned relation, a first lever means disposed between the middle and upper units, means pivotally mounting the first lever means intermediate its ends, two movable contacts connected to the first lever means adjacent its two ends, one of the contacts movable within an end unit and the other movable contact movable within the center unit, a second lever means disposed between the middle and lower units, means pivotally mounting the second lever means intermediate its ends, two

'movable contacts connected to the second lever means adjacent its two ends, one of the contacts movable within the center unit, the other movable contact movable within the lower unit, a piston member forming an extension of one of the movable contacts and movable within the unit ad.- jacent to which is the unit in which the movable contact moves, an operating rod movable axially of the assemblage, and means pivotally interconnecting the operating rod and the two lever means.

15. In a circuit interrupter of the fluid blast type, an arc extinguishing assemblage comprising two serially related arc extinguishing units disposed in axially aligned relation, rotatable lever means positioned between the two units, means pivotally mounting the lever means intermediate its ends, contact means in one of the units for establishing arcing therein including a movable contact operatively connected to the lever means adjacent one end thereof, other contact means in the other of the units for establishing arcing therein including a movable contact operatively connected to the lever means adjacent the other end thereof, fluid passage means interconnecting the two units, and substantially transverse fluid blast passage means disposed adjacent the region of arcin in One of the units to receive fluid through the first-mentioned passage means from the other unit and direct it against the arc. 1

16. In a circuit interrupter of the fiuid blast type, an arc extinguishing assemblage comprising two serially related arc extinguishing units 7 disposed in axially aligned relation, rotatable lever means positioned between the two units, means pivotally mounting the lever means intermediate its ends, contact means in one of the units for establishing arcing therein including a movable contact operatively connected to the lever means adjacent one end thereof, other contact means in the other of the units for establishing arcing therein including a movable contact operatively connected to the lever means adjacent the other end thereof, fluid passa e means interconnectin the two units, and means at least partially of insulation defining a constricted arcin slot adjacent the established arc in one of the units to facilitate extinction of the arc.

1'7. In a circuit interrupter, an arc extinguishing assemblage comprising three serially related arc extinguishing units disposed in axially aligned relation, a first lever means disposed between the middle and upper units, means pivotally mounting the first lever means intermediate its ends, two movable contacts connected to the first lever means adjacent its two ends, one of the contacts movable within an end unit and the other movable contact movable within the center unit, a second lever means disposed between the middle and lower units, means pivotally mounting the second lever means intermediate its ends, two movable contacts connected to the second lever means adjacent its two ends, one of the contacts movable within the center unit, the other movable contact movable within the lower unit, a fifth movable contact movable within one end unit, a third lever means, means pivotally mounting the third lever means, and means operatively connecting the fifth movable contact adjacent one end of the third lever means.

18. In a circuit interrupter, an arc extinguishing assemblage comprising three serially related arc extinguishing units disposed in axially aligned relation, a first lever means disposed between the middle and upper units, means pivotally mounting the first lever means intermediate its ends, two movable contacts connected to the first lever means adjacent its two ends, one of the contacts movable within an end unit and the other movable contact movable within the center unit, a second lever means disposed between the middle and lower units, means pivotally mounting the second lever means intermediate its ends, two movable contacts connected to the second lever means adjacent its two ends, one of the contacts movable within the center unit, the other movable contact movable within the lower unit, a fifth movable contact movable within one end unit, a third lever means, means pivotally mounting the third lever means, means operatively connecting the fifth movable contact adjacent one end of the third lever means, and operating rod means connected to the three lever means to cause their simultaneous rotation.

19. In a circuit interrupter of the liquid break type, an arc extinguishing assemblage comprising three serially related arc extinguishing units disposed in superimposed relation, a stationary contact disposed in each end unit, a movable contact cooperable with each stationary contact to establish an arc in each end unit, two movable contacts movable within the center unit, a first lever means interconnecting the movable contact associated with an end unit with one of the two movable contacts associated with the center unit, a second lever means interconnecting the movable contact associated with the other end unit with the other movable contact associated with the center unit, and magnetic means in at least one of the units to cause lateral motion of the arc established therein.

20. In a circuit interrupter, an arc extinguishing assemblage comprising two serially related arc extinguishing units disposed in axially aligned relation, rotatable lever means positioned between the two units, means pivotally mounting the lever means intermediate its ends, a movable contact connected to the lever means adjacent one end thereof and movable within one of the two units, another movable contact connected to the lever means adjacent the other end of the lever means and movable within the other unit, piston member forming an extension of the second-mentioned movable contact and movable into the first-mentioned unit, passage means interconnecting the two units so that fluid under pressure from one unit may flow through the passage means into the other unit, and magnetic means in at least one unit to efiect lateral motion of the are established therein.

21. In a circuit interrupter, an arc extinguishing assemblage comprising two serially related arc extinguishing units disposed in axially aligned relation, rotatable lever means positioned between the two units, means pivotally mounting the lever means intermediate its ends, a movable contact connected to the lever means adjacent one end thereof and movable Within one of the two units, another movable contact connected to the lever means adjacent the other end of the lever means and movable within the other unit, a piston member forming an extension of the second-mentioned movable contact and movable into the first-mentioned unit, an operating rod movable axially of the two units, means pivotally interconnecting the operating rod and the lever means, and passage means interconnecting the two units so that fluid under pressure from one unit may flow through the passage means into the other unit.

22. In a circuit interrupter, an arc extinguishing assemblage comprising two serially related arc extinguishing units disposed in axially aligned relation, rotatable lever means positioned between the two units, means pivotally mounting the lever means intermediate its ends, a movable contact connected to the lever means adjacent one end thereof and movable within one of the two units, another movable contact connected to the lever means adjacent the other end of the lever means and movable within the other unit, a piston member forming an extension of the second-mentioned movable contact and movable into the first-mentioned unit, an operating rod movable axially of the two units, means pivotally interconnecting the operating rod and the lever means, magnetic means in at least one unit to efiect lateral motion of the are established therein, and a conducting member for engaging the operating rod in abutting relation to cause the closing motion thereof.

23. In a circuit interrupter, an arc extinguishing assemblage comprisin two serially related arc extinguishing units disposed in axially aligned relation, rotatable lever means positioned between the two units, means pivotally mounting the lever means intermediate its ends, a movable contact connected to the lever means adjacent one end thereof and movable within one of the two units, another movable contact connected to the lever means adjacent the other end of the lever means and movable within the other unit, passage means interconnecting the two units so that the are established in one of the units may force fluid through the passage means into the other unit, means defining a restricted slot adjacent the are established in one unit, and magnetic means for biasing the are within the slot.

24. A circuit interrupter including operating rod means, rotatable lever means making a substantially acute angle with respect to the operating rod means, means pivotally mounting the rotatable lever means intermediate the ends thereof, another rotatable lever means making a substantially acute angle with respect to the operating rod means, means pivotally mounting the said other rotatable lever means intermediate the ends thereof, means interconnecting the operating rod means with both rotatable lever means to cause their simultaneous rotation, the said connection being on opposite sides of the pivotal mounting of the two rotatable lever means,'a pair of movable contacts, means operatively connecting the pair of movable contacts adjacent opposite ends of the first said rotatable lever means and causing the motion of the pair of movable contacts in a direction substantially longitudinally of the operating rod means, a third movable contact, means operatively connecting the said third movable contact adjacent one end of the said other rotatable lever means and causing the motion of the said third contact in a direction substantially longitudinally of the operating rod means.

25. A circuit interrupter including operating rod means, a pair of movable contacts, rotatable lever means making a substantially acute angle with respect to the operatin rod means, means pivotally mounting the rotatable lever means intermediate the ends thereof, another rotatable lever means making a substantially acute angle with respect to the operating rod means, means pivotally mounting the said other rotatable lever means intermediate the ends thereof, means interconnecting the operating rod means with both rotatable lever means to cause their simultaneous rotation, the connection being on opposite sides of the pivotal mounting of the two rotatable lever means, means operatively connecting the said pair of movable contacts adjacent opposite ends of the first said rotatable lever means and causing the motion of the said pair of movable contacts in a direction substantially longitudinal of the operating rod means, a third movable contact, means operatively connecting the said third movable contact adjacent one end of the said other rotatable lever means and causing the motion of the said third movable contact in a direction substantially longitudinal of the operating rod means, piston means including a movable piston member, and means operatively connecting the movable piston member adjacent the other end of said other rotatable lever means.

26. A circuit interrupter including an are extinguishing assemblage, the arc extinguishing assemblage including two serially related are extinguishing units disposed in axially aligned relation, operating rod means extending axially of the arc extinguishing assemblage, rotatable lever means positioned between the two units and making a substantially acute angle with respect to the operating rod means, means pivotally mounting the rotatable lever means intermediate the ends thereof, another rotatable lever means disposed on the other side of one of the units and making a substantially acute angle with respect to the operating rod means, means pivotally mounting the said other rotatable lever means intermediate the ends thereof, means interconnecting the operating rod means with both ro tatable lever means to cause their simultaneous rotation, the connection being on opposite sides of the pivotal mounting of the two rotatable lever means, a pair of movable contacts, one of which moves in each of the two are extinguishing units, means operatively connecting the pair of movable contacts adjacent opposite ends of the first said rotatable" lever means and causing the motion of the pair of movable contacts in a direction substantially axially of the arc extinguishing assemblage within the arc extinguishing units, a third movable contact movable within said one of the arc extinguishing units, means operatively connecting the third movable contact adjacent one end of the said other rotatable lever means and causing the motion of the third movable contact in a direction substantially axially of the arc extinguishing assemblage.

27. A circuit interrupter of the liquid break type including an arc extinguishing assemblage, the arc extinguishing assemblage including two serially related arc extinguishing units disposed in axially aligned relation, operating rod means extending axially of the arc extinguishing assemblage, rotatable lever means positioned between the two units and making a substantially acute angle with respect to the operating rod means, means pivotally mounting the rotatable lever means intermediate the ends thereof, another rotatable lever means disposed on the other side of one of the units and making a substantially acute angle with respect to the operating rod means, means pivotally mounting the said other rotatable lever means intermediate the ends thereof, means interconnecting the operating rod means with both rotatable lever means to cause their simultaneous rotation, the connection being on opposite sides of the pivotal mounting of the two rotatable lever means, a pair of movable contacts, one of which moves in each of the two arc-extinguishing units, means operatively connecting the pair of movable contacts adjacent opposite ends. of the first said rotatable lever means and causing the motion of the pair of movable contacts in a direction substantially axially of the arc-extinguishing assemblage within the arc-extinguishing units, a third movable contact movable within said one of the arcextinguishing units, means operatively connecting the third movable contact adjacent one end of the said other rotatable lever means and causing the motion of the third movable contact in a direction substantially axially of the arc-extinguishing assemblage, a piston member movable within the said one of the arc-extinguishing units, and means operatively connecting the piston member adjacent the other end of the said other rotatable lever means.

WINTHROP M. LEEDS. JAMES M. CUMMING.

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

UNITED STATES PATENTS Number Name Date 862,513 Robinson Aug. 6, 1907 1,847,463 Austin Mar. 1, 1932 2,039,054 Boden et al Apr. 28, 1936 2,084,885 Biermanns June 22, 1937 2,098,801 Erben Nov. 9, 1937 2,141,279 Sadler Dec. 27, 1938 2,154,515 Leeds Apr. 18, 1939 2,155,263 Fiurscheim Apr. 18, 1939 2,292,547 Sadler Aug. 11, 1942 2,394,046 Dickinson Feb. 5, 1946