US2099639A - Circuit breaker - Google Patents

Description

Nov. 16, 1937. 1 Q WOOD 2,099,639

C IRCUIT BREAKER Filed Nov. 18, 1935 /Lw ATTORNEY Patented Nov. 16, 1937 UNITED STATES PATENT OFFICE CIRCUIT BREAKER York Application November 18, 1935, Serial No. 50,299

Claims.

This invention relates to circuit breakers and more particularly to an improved method and structure for reducing the arcing upon opening the contacts of oil circuit breakers.

The present invention is shown applied to the form of contacts disclosed in my prior Patent No. 1,974,525, granted September 25, 1934 but may be embodied in other structures than the particular form shown.

One object of the present invention is to cause the breaking of the arc under a reduced distance o1' opening movement of the contacts. Another object is to reduce the tank pressure upon the opening of the breakers. Another object is to reduce the burning of the contacts and to reduce the deterioration of the breaker to a minimum. Another object is to quickly quench the arc upon the opening of the breaker and to increase the safety factors, Another object is to produce a simple, dependable and durable form of construction for accomplishing the above objects. Other objects and advantages of this invention will be understood from the following description and accompanying drawing which show a preferred embodiment.

Fig. 1 is a side view of a pair of circuit breaker contacts with a bridging member partly in section and showing the oil tank in section, the breaker being shown in an opening position;

Fig. 2 is a plan View of cooperating contacts on the line 2 2 of Fig. 1 and showing the parts in closed position; and

Fig. 3 is a side View of cooperating contacts shown in closed position.

Referring to Fig. l, the usual tank 5 surrounds the contacts of the breaker and contains oil maintained at a desirable level to cover the contacts. Only one set of contacts is shown, but it will be understood that any number thereof may be used and their movement controlled in any way desired. A pair of insulators 6 is supported in the top portion of the tank and envelop the conductors leading to the main contacts l. These contacts are laminated and flexible to insure good contact with the bridging member. The contacts I are bent and pressed against plates 8 and are clamped in place by the plates 9, the parts being held together immediately below the insulators 6 by bolts and nuts ID.

An auxiliary xed arcing Contact of metal is also clamped to each main contact at its upper end by the bolts and nuts I0, each of these auxiliary contacts being held in place on the outside of each clamp 8. Each auxiliary arcing member has a main portion I I extending downwardly and on its outer lower end has an outwardly projecting arcing contact portion I2. The portion I2 may be integral with the portion II or secured thereto by screws I2a. These auxiliary contacts extend below the main contacts 1 and are spaced outwardly from them as shown in Fig. 1. The lower inside surface of each auxiliary contact is rounded to form a contact surface engaged by the auxiliary movable contact. The portion I2 of each auxiliary contact is rounded at its upper outer part I3 and forms a projection from the part I I for the nal path of the arc.

The bridging conducting member I4 is of inverted U-shaped form and is suitably secured to the upwardly extending operating rod I5 of suitable insulating material. The top surface of the bridging member I4 is adapted to engage the laminated main contacts 'l when raised to closed position.

The upper outer ends of the bridging member I 4 are cut away to form a pair of outwardly extending ears Ida at each end. Between these ears is mounted a rod I6 at each end of the bridging member. Upon each of the rods I8 is pivotally mounted an auxiliary movable Contact element I1. This may be a solid piece of metal or made up of two or more pieces clamped together. Its upper outer portion is rounded as shown at I'Ia so that when the bridging member is raised for closing the contacts, the rounded portion I la, of each auxiliary movable contact will engage the rounded lower inner portion of each of the auxiliary fixed contacts II. The auxiliary movable contacts Il are provided at each of their ends with an outwardly extending plate or flange I1b. These projecting side portions are adapted to embrace the lower portion of the auxiliary fixed contacts when in closed position, as shown in Figs. 2 and 3. Pins I8 pass through downward extensions I'Ic from each of the auxiliary contacts I'I and extend outwardly to serve as a stop for limiting the outward movement of the contacts by engaging the lower edges of the bridging member I4, as shown in Fig. l. A spring I9 is connected at one end to the pin I8 and at its other end to a pin I8a extending between the sides of the bridging member. The auxiliary contacts Il are thus biased to move outwardly toward the position shown in Fig. 1. A flexible conductor 2U is secured at one end to the bridging conductor and at the other end to the auxiliary contact I'l to form good electrical connection between the bridging conductor and its auxiliary contacts.

In operation, when the breaker is closed, the bridging member I4 is moved upwardly by the rod I5 causing the auxiliary contacts I'I to rst engage at the rounded portions I'la with the rounded portions of the auxiliary xed contacts I2. As the breaker continues the closing move- In the closed the current is first ruptured between the main contacts 'i and the bridging member i4, the cur-` rent continuing to pass through the auxiliarycontacts. As the downward movement continues, the auxiliary movable contacts Il move outwardly against the xed auxiliary contacts ll until the contact is broken, causing the formation of arcs between them. The continued downward movement of the bridging member causesrthe nal rupture of the current and the extinguishment of the arcs. Y

The quenching of the arcs at the auxiliary contacts is rapidly and effectively accomplished due to the combined effect of various forces. The electromagnetic action tends to force the arcs outwardly and the provision of side plates or flanges llb creates paths for the current to be forced outwardly from the rounded portions lla of the contacts and thus permit the arc to be forced by the electromagnetic action outwardly to the outermost tip of the flanges 17h'. The electromagnetic action also causes the path of the arc to move outwardly to the portions l2 of the auxiliary fixed contacts and move upwardly along the outer portion of these contacts until it reaches the rounded tip I3. This tip is a limiting position of the arc travel and results in the arc forming a path as indicated at 2l from the tips i3 to the tips or ends of the ilanges l'lb; and it should be appreciated that this arc is sub-divided into paths from the two flanges l'lb of each auxiliary contact to the tips I3 of the auxiliary fixed contacts. This forcing of the arcto the outward position described and to tips of thev cooperating auxiliary contacts by the electromagnetic field, together with the sub-division ofthe arc, results in such attenuation of the arc between limiting contact tips as to rapidly extinguish it. A further action occursbecause as the arc is forced outwardly into fresh and cooler oil in the manner described, a blast of fresh oil is caused to move outwardly between the contacts as indicated by the arrows 22 and strike against the arc to further hasten the quenching of the arc.

Comparative tests have shown that the present improvement has very marked advantages in the respects previously described, as compared with the results obtained by the construction shown and described in my prior Patent #1,974,525,

Although a preferred embodiment of this invention has been described, it will be understood that various modifications may be made without departing from the scope of the invention.

The invention claimed is:

l. A circuit breaker comprising a movable con,- ducting element, a xed conducting element, an auxiliary conducting element movable relatively to and carried by said movable conductingv element, said auxiliary conducting element having a contacting portion adapted to engage the inner face of the xed conducting element and having a side portion extending outwardly and embracing a side of said xed conducting elernentl in the closed position of the breaker, and means for biasing said Vauxiliary element outwardly t0 cause said contacting portion to engage theV inner face of said fixed conducting element and to cause said side portion to move outwardly Yrelatively to said xed conducting element upon the opening of the breaker. Y

2. A circuit breaker comprising a movable conducting element, a xed conducting element, an auxiliary conducting element pivotally mounted on said movable conducting element,

' said auxiliary conducting element having a contacting portion adapted to engage the inner face of the iixed conducting element and having a side portion extending outwardly and embracing a side of said xed conducting element in the closed position of the breaker, and a spring for biasing said auxiliary element outwardly to cause said contacting portion to engage the inner face of said fixed conducting element and to cause said side portion to move outwardly relatively to said fixed conducting element upon the opening of the breaker.

3. A circuit breaker comprising a movable conducting element, a xed conducting element, an auxiliary conducting element movable relatively to and carried by said movable conducting element, said auxiliary conducting element having a contacting portion adapted to engage the inner face of the fixed conducting element and having a side portion extending outwardly and embracing a side of said xed conducting element in the closed position of the breaker, and means for biasing said auxiliary element outwardly to cause said contacting portion to engage the inner face of said xed conducting element and to cause said side Vportion to move outwardly relatively to said fixed conducting element upon the opening of the breaker, said fixed conducting element having a portion projecting outwardly to cooperate with the tip of said side portion in carrying the arc at the time of rupture;

4. A circuit breaker comprising a movable conducting element, a fixed conducting element, an auxiliary conducting element movable relatively to and carried by said movable conducting element, said auxiliary conducting element having a central contacting portion adapted to engage the inner face of the xed conducting element and having side portions extending outwardly and embracing opposite sides of said fixed conducting element in the closed position of the breaker, and means for biasing said auxiliary element outwardly to cause said contacting portion to engage the inner face of said fixed conducting element and to cause said side portions to move outwardly relatively to said fixed conducting element upon the opening of the breaker.

5.A circuit breaker comprising a movable conducting element, a fixed conducting element, an auxiliary conducting element movable relatively to and carried by'said movable conducting element, said auxiliary conducting element having aV central contacting portion adapted to engage the inner face of the iixed conducting element and having side portions extending outwardly and embracing opposite sides of-said fixed conducting element in the closed position of the breaker, and means for biasing said auxiliary element outwardly to causesaid contacting portion to engage the inner face of said xed conducting element and to cause said side portions to move outwardly relatively to said xed conducting element upon the opening of the breaker, said fixed conducting element having a portion projecting outwardly to cooperate with the tips of said side portions in carrying the Varc at the time of rupture.

JOSEPH D. woon.

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