JPS6215726A - Circuit breaker - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a circuit breaker, and more particularly to a means for commutating an arc generated between opening contacts from a fixed contact to an arc chute.

Circuit breakers are widely used in industrial, residential, and commercial facilities to protect against damage caused by overcurrent conditions. As the use of electrical energy increases, so does the capacity of this energy source. As a result, large currents may flow in the power distribution network and short circuits may occur in this power distribution network. Under these conditions, conventional circuit breakers require that the equipment connected downstream from the circuit breaker,
and failure to prevent serious damage to the circuit breaker itself.

When an extreme overcurrent condition occurs in a circuit breaker, a large electromagnetic force is generated in the contact arm that causes it to pivot rapidly in the opposite direction, causing the contacts to open. That is, an arc is formed resulting in high arc voltage and arc resistance, resulting in a current limiting effect. An associated tripping means quickly releases the operating mechanism from the closed condition to the open condition before the contact arm returns to the closed condition, thereby preventing re-firing.

The present invention includes an insulating casing having a line terminal and a load terminal, a separable contact disposed inside the casing to open and close a circuit between the terminals,
an operating mechanism having a pivoting carriage and means for manually pivoting the carriage between an open position and a closed position, first and second pivoting contact arms each supporting one of the contacts; A contact support means in which the first contact arm is pivotally attached to the carriage; means for restricting the relative movement of the carriage and the first contact arm to rotation; a conductor connecting the line terminal and the second contact arm;1. Arc extinguishing means arranged around the six-movement path of the first contact arm, arc absorbing plates keeping a distance from each other, connecting the conductor to one arc absorbing plate, and when an arc occurs, it is transferred from the second contact arm to one of the arc absorbing plates. A circuit breaker is provided comprising means including electrical connector means for commutating current to an arc absorbing plate.

The advantages of the device of the present invention are that the arc moves from the arc to the arc chute more quickly than before, resulting in higher arc voltage than before, more effective arc interruption than before, and less contact wear than before. It becomes possible.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

The three-pole circuit breaker 3 shown in FIG. 1 includes an insulating housing 5 consisting of a base 7 and a cover 9 fixed to the base in a known manner, such as by screws (not shown). Although the principle of the present invention can be applied to single-pole circuit breakers, it is often applied to multi-pole circuit breakers, so the housing 3 is configured to combine three horizontally adjacent pole units in a known manner. Includes an insulating barrier separating the comparators.

A circuit interrupting mechanism 11 is installed in the central pole unit of the housing, consisting of a single operating mechanism and a single latching mechanism 15. The circuit interrupting mechanism 11 also includes a separate thermal device 17 and a fast electromagnetic trip device 18 for each of the three pole units. A typical high speed electromagnetic trip device is described in detail in US Pat. No. 4,220,935.

The multipole circuit breaker has a pair of separable contacts 19.21, which are fixed to upper and lower contact arms 20.22, respectively. Each pole unit includes an arc extinguishing means or arc chute 23. The upper contact 19 (made of conductive material)
It is electrically connected via an upper contact arm 20 to a shunt 24 which is connected to a terminal 26 via a conductive piece 25, a thermal device 17 and a magnetic disconnect device 18.

Lower contact 21 is connected to terminal 29 via lower contact arm 22 and conductive piece 27 . Therefore, if the circuit breaker 3 is in the closed state, some elements 27, 22 from the terminal 29
．． An electric circuit is established to terminal 26 through 21.19.20.24.25.

The contact arm 20 is pivotally connected at a pivot 33 to a rotating carriage 34 which is fixed to an insulating rotating tie bar 35 . Carriage 34 includes a slot or pocket 37 in which end 39 of arm 20 is rotatably attached to pivot 33 . When a normal current is flowing through the circuit breaker, the arm 20 and the carriage 34 rotate together with the tie bar 35.

The single operating mechanism 11 is located in the center pole unit of a three-pole circuit breaker and includes a pair of non-flexible support plates (only one is shown in the drawing) fixed to the base 7 of the circuit breaker center pole unit. It is supported by 41. An inverted U-shaped operating lever 43 is pivotably supported on this support plate 41, which is spaced from one another, the leg end of which is arranged in a U-shaped cutout 45 in the plate. The operating lever 43 includes a handle 47 made of molded electrically insulating material.

The contact arm 20 of the central pole unit is connected to the upper toggle link 4
7 and a lower toggle link 49 releasably interlock with the ladle member 51. The toggle links are connected to each other by knee pivot pins 53. The lower toggle link 49 is pivotally connected to the central pole unit carriage 34 by a pin 33, and the upper toggle link is pivotally connected to the ladle member 51 for release by a pivot pin 55.

An overcenter action spring 57 is stretched between the pivot knee pin 53 and the curved portion of the operating lever 43.

Turn the handle 47 from the ON position (Fig. 1) to O on the right side of Fig. 1.
Contacts 19.21 are manually opened by moving them to the FF position. Turn the handle 47 to the right (to the OFF position)
When it is moved, the line of action of the over-center operating spring 57 moves to the right, folding the toggle links 47 and 49, rotating the crossbar 35 in the direction of the hour hand, and simultaneously moving the contact arms 20 of the three pole units to the open position 6 to open the contacts of the three pole units. At this point, contact arm 2
0 comes at the dashed line position (FIG. 1).

Conversely, move the handle to the left and release the overcenter spring 5.
Move the line of action of 7 to the left and toggle link 47.49
The contacts are manually closed by moving the contacts to the FIG. 1 position. Along with this operation, the crossbar 35 rotates in the counterclockwise direction, causing the contact arms 20 of the three pole units to move six times to the closed position.

A latching mechanism 15 consisting of a lever actuated by a trip device 17, which may be an electronic or thermomagnetic trip mechanism (not shown in detail), releasably latches the ladle member 51 in the position of FIG. The trip mechanism 17 is capable of sensing both low level short circuit or overload current conditions as well as high level short circuit or fault current conditions. When such a state is detected, the tripping mechanism 17 starts the tripping operation of the operating mechanism 13 by rotating the latch mechanism or lever 15 in the direction of the hour hand.

In the present invention, the lower arc plate 24 of the arc chute 23 is physically and electrically connected to the conductor 27 by a connector 59 such as a screw or bolt. When the circuit is closed, lower and upper contact arms 22 .
The fault current flows through the reverse loop formed by 20.

When the circuit breaker is tripped by tripping mechanism 15 or by upper contact arm 20 being "blown open" at position 20a (FIG. 1), contacts 19.
The arc generated between 21 and 21 is diverted to the lower arc plate 24 and from there to the upper contact arm 2 as shown by arrow 63.
It reaches 0a. Since the arc plate 24 is connected to the conductor 27, the arc 63 takes the path of least resistance, ie, is commutated to the arc plate 24. The arc current bus 63 thus formed bypasses the reverse loop 61 by passing through the conductor 59 and reaching the conductor 27 .

Ultimately, arc chute 23 extinguishes arc 63 in a known manner.

Another embodiment of the invention is shown in FIG. 2, where like parts have been given the same reference numerals. In Figure 2, the lower arc plate 2
4 is connected to the conductor 27 via a non-flexible or flexible connector 65 such as a stop, cable, shunt, etc. Similar to connector 59 (FIG. 1), connector 65
serves to prevent the arc from moving towards the lower contact arc 22 after the arc 63 has been commutated to the lower arc plate 24 .

In another embodiment of the invention (FIG. 3), the lower arc plate 24 has a bend 28 connecting the plate 24 to the conductor 77.
including. Similar to connector 59 (FIG. 1), the curvature 28 prevents the arc 63 from moving toward the lower contact arm 22 after it has been commutated to the lower arc plate 24.

Since the lower contact arm typically does not immediately commutate the arc to the arc chute under low-level fault conditions,
Connector 59.65.28 transfers the arc from the lower contact arm to the arc chute, thereby forming a reverse loop 71.
bypass. When contacts 19.21 open, the arc 63
is blown into the arc chute 23.

If a moderate fault occurs, the arc will be commutated from the lower contact arm to the arc chute where the magnetic field is generated. When the arc contacts the plate of arc chute 23, the arc senses a relatively low potential path in lower arc plate 24. When relatively high level fault conditions occur,
The arc is blown into the chute 23 by the magnetic reaction, and the arc becomes longer as the arc voltage increases in proportion to the arc length.

In conclusion, the circuit breaker of the present invention allows six lines of arcing from the contacts to the arc chute under low level fault conditions. The lower contact arm being close to the lower arc plate allows the arc to transfer from the contact arm to the plate. Moreover, the dual advantages of extending the service life of the contacts and enhancing the arc cooling effect are obtained.

[Brief explanation of the drawing]

FIG. 1 is a vertical sectional view showing a multi-pole current-limiting circuit breaker in a closed contact state. 2 and 3 are partial cross-sectional views showing other embodiments of the present invention. 19.21...Contact 22...Contact arm 23...Arc chute 24...Lower arc plate 65...Connector luxury

Claims (1)

[Claims] 1. An insulating casing having a line terminal and a load terminal, a separable contact disposed within the casing for opening and closing a circuit between the terminals, a rotating carriage, and a carriage that can be moved to an open position by manual operation. an operating mechanism having means for pivoting to and from a closed position, the operating mechanism including first and second pivoting contact arms each supporting one of the contacts, the first contact arm being pivotally mounted to the carriage; means for restricting the relative movement of the carriage and the first contact arm to rotation; a conductor connecting the line terminal and the second contact arm; arc extinguishing means disposed around the movement path of the first contact arm; and arc absorbing plates spaced apart from one another, means including electrical connector means for connecting the conductor to one of the arc absorbing plates and commutating an arc from a second contact arm to one of the arc absorbing plates. . 2. Biasing means is provided for biasing the first contact arm to the first position relative to the carriage so that the first contact arm and the carriage can rotate together to open and close the releasable contact. A circuit breaker according to claim 1, characterized in that: 3. A patent characterized in that the arc absorbing plate includes a plurality of plates adjacent to the second arm when the contacts are closed and a plurality of other plates that are not adjacent, and the electrical connector means connects the conductor to one of the adjacent plates. A circuit breaker according to claim 2. 4. The circuit breaker according to claim 3, wherein the second arm is disposed within the plane of the adjacent plate. 5. The circuit breaker according to claim 4, wherein the conductor is disposed on the opposite side of the second arm from the first arm, and a connector connects the conductor to the nearest plate. 6. The circuit breaker according to claim 5, wherein the connector may be a non-flexible member or a flexible member.