US2644877A

US2644877A - Rotary circuit breaker

Info

Publication number: US2644877A
Application number: US229359A
Authority: US
Inventors: Guillaume Andre
Original assignee: Forges et Ateliers de Constructions Electriques de Jeumont SA
Current assignee: Forges et Ateliers de Constructions Electriques de Jeumont SA
Priority date: 1950-06-09
Filing date: 1951-06-01
Publication date: 1953-07-07
Anticipated expiration: 1970-07-07
Also published as: BE465350A; US2507971A; GB615749A; DE864122C; FR54495E; FR60380E; BE503343A; FR916847A; DE839218C; GB683116A

Description

July 7, 1953 A. GUILLAUME ROTARY CIRCUI'I` BREAKER Filed June 1, 1951l MATERIAL M Figi 'T-NvEmfoR: ANDR GmLLAuME BY wmmmvm ATTORNEYS the circuit breaker.

Patented July 7, 1953 ROTARY CIRCUIT BREAKER Andr Guillaume, La Plaine Saint-Denis, Seine, France, assignor to Societe Anonyme dite: Forges et Ateliers de Constructions Electriques de Jeumont, `Paris, France, a corporation of A France Application June 1, 1951, Serial No. 229,359 In France June 9, 1950 5 Claims. l

The present invention relates to improvements in rotary circuit breakers of high breaking power, the rotary contacts of which operate in a small volume of oil; see for instance U. S. Pat. No. 2,507,971.

It has previously been proposed to immobilize the arcs of such circuit breakers by means of circular arc-guiding channels in which the rotary contacts move, the arcs being maintained in the interior of these channels by the flow of quenching fluids exhausted from the interrupting chamber.

A primary object of the present invention is to reduce the mechanical forces (pressures) which appear in circuit breakers of this type and, by such reduction, to improve the performance of the circuit breaker and to increase its so-called breaking power.

A further object of the invention is to improve the xation of arcs and the blow-out effect of the t quenching fluids.

The foregoing objects are realized by the present inventionwhich involves a special construction and arrangement of rotary contacts and of arc-guiding channels, the latter being directly associated with damping means disposed in their immediate vicinity.

According to the invention, the arc fixation channels have the form of relatively deep annular grooves of substantially trapezoidal crosssection, the axis of symmetry of the said crosssection being parallel to the axis of rotation of Moreover, the said guiding channels are interconnected with chambers, in the form of recesses or bores or the like, which are partially lled with oil and are positioned in the immediate vicinity of said channels in order to damp and lengthen the time of effectiveness of, the hydraulic flow effects which appear in the said channels.

Additional features and objects of the present invention will be evident from the following description, with reference to the accompanying sheet of drawings, of a presently-preferred exemplary embodiment of the invention.

On the said sheet of drawing, Fig. 1 is a somewhat diagrammatic section through a two-arc interrupting chamber, Fig. 2 is a horizontal crosssection taken along line I-I of Fig. l, and Fig. 3 is a similar cross-section taken along line II-II of Fig. 1.

The aforesaid chamber is a cylindrical housing formed by a stationary cylinder 'I of insulating material and two spaced end plates I6 and I8 of insulating material fixed in the interior thereof,

as shown. Rotary shaft I, also of insulating material, is mounted to rotate within the said cylinder l and plates IG and I8. The shaft I passes without appreciable play through the circular openings provided in plates or partitions I6 and I8, which are reinforced by additional end partitions I5 and I1. Shaft I carries two spaced electrically conductive contact-arms 2, which cooperate, respectively, with

xed contacts

3 and 4. Rotary contacts 2 are electrically interconnected by a suitable conductive connector member 2a arranged as shown interiorly of shaft I which, to this end, may be tubular. Each contact arm 2 ls bent in the manner illustrated on the drawing so that the terminal end thereof extends in a direction parallel to shaft I.

The end of the upper contact 2 moves within downwardly-opening annular channel 9, provided for the guidance of the upper arc and being formed in the upper insulating plate IB. Channel 9 is relatively deep and takes the form of a downwardly-opening annular groove having a trapezoidal cross-section with smooth angles, which facilitates the flow of oil and enables the realization of a very effective fixation in space as well as an efficient quenching of the upper are which is formed between upper contact 2 and fixed contact 3 which, as shown, is located in the channel 9.

The downwardly extending end of the lower rotary contact member 2 moves within a similar upwardly-opening channel 9a, provided in the plate I8 for the guidance of the lower arc which is formed between said contact 2 and a xed contact 4, located as shown, in channel 9a enclosing the path of the said lower contact 2. The

vdescribed relationship of parts effects an eficient immobilization and quenching of the said lower arc.

Channel 9 comprises a plurality of blow-out and exhaust openings I0 extending upwardly from the bottom of the annular groove thereof through to the upper surface of plate I6. Outlet openings Ill are spaced in circular arrangement around shaft I in alinernent with upwardly outwardly-iiared passages I3 extending through the outer plate I5 of insulating material, mounted on plate I6. It will be understood that the passages I3, which correspond in number to the openings I0, are, like the latter, disposed in circular arrangement in plate I5 around shaft I. The passages I0, I3 have preferably the form of vconventional blow-out nozzles, the effect of which, in combination with the cross-sectional form of channel 9, is to facilitate the exhaust connected to the latter, as shown.

now and to produce a very enicient deionization of the upper arc.

A number of downwardly-opening chambers I9, which may for instance be in the form of bores, are provided in. plate I6. These chambers are disposed in circular arrangement around shaft I, as shown in Fig. 2. A similar series of downwardly-opening recesses or bores ISa is provided in plate I5, while a similar series of recesses or bores and 20a is also provided in each. of annuli I8 and Ia, respectively, according to Fig. 3. These recesses or bores I9, I9a, 2U and 20a are partly lled with oil, the upper portion of each bore being filled with gas produced by previous interruptions, so that all recesses operate as yielding elements after the manner of dash-pots or shock absorbers. In order more enilciently to damp and prolong (i. e. extend over an increased period of time) the pressure eiects which arise in the interior of

channels

9 and 9a and to better immobilize the arcs in these channels, the recesses or bores I9, IHCL, 29 and 29a are positioned in close proximity to, i. e. in the immediate vicinity of, the said channels and are Bores I9a are connected to channel 9 by way of short conduits 2l, while

bores

20 and 20a are connected. to channel 9a by way of short conduits 22 and 22a, respectively. This arrangement makes it possible for the gases produced by the arcs to collect in the upper portions of the said bores and, by the compression of such trapped gas', to produce currents of oil which improve the fixation. or localization of the arcs in both

channels

9 and 9a.

In consequence of the described relationship of parts, the upper arc is maintained in its blowout position in the interior of channel 9, not only by the fluids which are exhausted through orices i3 but also by the fluids which move through conduits 2| to bores I9a. The lower arc is maintained at the bottom of channel 9a by the fluids which pass through conduits 22 and 22a to recesses 2U and 29a.

It is known that the gases which are formed suddenly by arcs of interruption give rise to overpressures of two kinds. The one type of overpressure, relatively moderate, has a relatively long duration of the order of a fraction of a second; the other type of overpressure is of the impulse type, the waves of which have a very steep front of short duration but With very high peak values which may exceed the limits of strength of the apparatus.

When the gas-filled cavities are remote from the arcs, as in known apparatus these overpressure impulses are propagated and are reilected throughout the apparatus, subjecting the latter to very high stresses. On the other hand, when the said cavities are positioned, in accordance with the present invention, practically at the Very point where the said steep front waves of pressure are created, these waves are absorbed on the spot and only the moderate overpressures, relatively slow in their formation and action, pro- 4 duce the proper acceleration of the oil to assure energetic and prolonged blowing of the arc.

These moderate overpressures produce a prolonged fiow of deionizing fluids through the upper channel 9 and blow-out passages IIJ, I3, the nozzle type of which facilitates the How-out and appreciably improves the blow-out.

As a result, the present device is capable of breaking more powerful arcs without producing excessive pressures, i. e. the apparatus has an increased breaking power.

It will be understood that the chamber defined between plates I6 and I'I and cylinder 'I is lled with oil or other suitable quenching fluid up to level 8; also that the

contacts

3 and 4 are severally connected with

lead wires

5 and 6.

Having thus disclosed the invention, what is claimed is:

1. In a rotative high-power circuit breaker of the low oil-volume type comprising an interrupting unit including an insulating housing having spaced upper and lower end walls deiining upper and lower circular arc-guiding channels with outlet openings from the upper channel, and also comprising a ixed contact in each` of said channels and a rotatable contact engageable with each of said fixed contacts, at least one circularly-arranged series of downwardly opened gas- Hlled damping chambers in each of said upper and lower walls, said circular series being arranged in the immediate vicinity of the corresponding circular channel, and each said channel having a trapezoidal cross-section with smooth angles, the axis or" symmetry of this cross-section being parallel to the axis of rotation of said circuit breaker.

2. A relationship of parts according to claim 1, wherein each of said end walls comprises a plurality of circularly-arranged series of said damping chambers which have the form of vertical bores which. retain a part of the gases produced by the arcs.

3. A relationship of parts according to claim 1, wherein the active end portions of said rotatable contacts extend inside of said circular channels parallel to said axis of rotation.

4. A relationship of parts according to claim 1. wherein said outlet openings have the form of hydraulic blow-out nozzles interconnecting said upper channel with the outside.

5. A relationship of parts according to claim 1, and short interconnections between said circular channels and the lower parts of the associated damping chambers, said interconnections being located in the immediate vicinity of the arcs.

ANDR GUILLAUME.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 2,239,243 Monchamps Apr. 22, 1941 2,452,477 Leeds Oct. 26, 1948 2,467,788 Van Sickle Apr. 19, 1949 2,507,971 Guillaume et al. May 16, 1950